Concurrency:

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Part II Concurrency Information Management
Challenge
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Concurrent Engineering (called also simultaneous
or life cycle engineering) is a philosophy that
attracts increasing attention of systems science
community and systems analysts working in various
application areas. CE addresses the issues of a
major technological change from sequential to
simultaneous engineering. It requires that system
analysts and designers understand how to acquire,
process, and integrate information concerning
various stages of a life-cycle of a product. It
is a systematic approach that enables cooperative
work among all groups that plan, design, produce,
maintain and support the product over its life
cycle. It calls for multidiscipline teamwork and
promotes collaboration and application of
different skills and knowledge sources.
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Many definitions of concurrent engineering exist.
The main difference is on the topics covered
within the definition. The definition that is
broadly adopted within CE research community was
proposed by The Institute for Defence Analyses in
its IDA Report R-338 in 1988 Concurrent
Engineering is a systematic approach to the
integrated, concurrent design of products and
their related processes, including manufacture
and support. This approach is intended to cause
the developer from the outset, to consider all
elements of the product life cycle from
conception through disposal, including quality,
cost, schedule and user requirement.
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• The traditional design philosophy was a result of
  increased specialisation and departmentalisation
  in periods of rapid growth after the Second World
  War. This led to a design process often called
  over the wall design, where the design would be
  passed over the wall from department to
  department with little consultation or
  coordination. The main features of the
  traditional design philosophy are
• Sequential design process
• Specialisation
• Over the wall design
• Limited concept development

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• This approach led to the following problems
• As the work of departments was not integrated,
  each department would attempt to maximise their
  own output, not the overall output.
• Downstream functions were rarely consulted in the
  early stages when most of the significant design
  decisions were being made.

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• Designs would have to be redone or altered as
  problems were identified by downstream
  departments. This added greatly to the time
  required for a design to be completed.
• The above problems led to mistrust between
  departments as products below expectations were
  produced.
• With little consultation between departments
  misunderstandings are more common and the
  constraints of other departments are not always
  known.

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Apart from the reasons outlined above, there are
three primary reasons that require a change from
the traditional design process Rapid pace
of technology. Due to increased competition,
technology is advancing at an ever faster pace.
To maintain market share the use of new
technologies is often required. This required
designs to be produced at ever quicker rates with
increased complexity of design.
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Forced design cycle compression. With less time
designers often attempted to ignore the input
from other functions so as to shorten cycle time.
This resulted in a situation where problems
would have to be addressed later in the
development cycle often increasing cycle times
and delivering an inferior product. Emerging
information technology and methodologies. With
the emergence of new tools and techniques, a new
design philosophy was required to take full
advantage of these advances. Thus a design
methodology was required that would reduce
development time while considering the input of
all relevant functions to the design process.
Concurrent Engineering satisfies these criteria.
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The advantages of concurrent engineering can be
delineated in terms of two broad
categories 1. Reduction in product development
lead time Concurrent engineering performs the
product development activities on a parallel
rather than on a sequential basis. This concept
can potentially reduce the entire product design
cycle time and contribute to significant
reduction of duplication of effort and future
costly product redesigns. This benefit of
concurrent engineering is achieved when an
efficient flow of information and communication
exists among various decision makers in the early
phases of product development. This advantage, in
an ultimate sense, contributes to more efficient
operation and higher productivity.
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2. Overall cost savings Concurrent engineering
designs for manufacturability. Process planning
activities are streamlined in such a way that
total product costs can be reduced. This may be
in the form of reduction in the number of parts
to be manufactured, better machine utilization
time, easier manufacturable parts, lesser reworks
and scraps, greater use of standard features
resulting in standard tooling and reduced costs,
lower changes in process planning due to lower
number of part redesigns.
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INFORMATION FLOW ARCHITECTURE FOR CONCURRENCY
EVALUATION
Concurrent approach must simultaneously embrace
the life cycle and concurrency analysis refers to
the integration of various values (concurrency
attributes) within the broad scope of acquisition
and utilization. This values include not only the
main functions of the product but also its
aesthetics, manufacturability, assemblability,
reliability, serviceability, and so on. System
development process should thus incorporate, at
its various stages, a number of concurrency
attributes. As a consequence, this means that it
also undergoes a multicriteria evaluation that is
included in the design process as presented in
the Figure.
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Design as a goal-seeking system
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Sample concurrency attributes
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Architecture of the proposed system
Concurrency agents are associated with
concurrency attributes a1, a2, ..., an. Agents
cooperate and contribute to the global degree of
concurrency satisfaction denoted by Ff(a1, a2,
..., an). The degree of satisfaction of a given
concurrency attribute simulates the judgment on
how well a system satisfies the requirements
associated with the corresponding attribute.
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Each system imposes different values on the
degree of satisfaction of concurrency attributes.
For example, a throw-away product may be assigned
the required degree of serviceability
satisfaction as 0 in the scale 0 to 1 (it does
not need to be serviced), and the required degree
of manufacturability as close to 1 (it must be
inexpensive and therefore easily manufacturable).
Design of a coupling has a low value of the
degree of satisfaction of the aesthetic
attribute, but a high value for reliability. In
each case, the judgment of the degree of
satisfaction of the concurrency attribute is at
least partially subjective and is based on the
available knowledge IT IS FUZZY.
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An agent can be described as a model of an
intelligent entity consisting of information and
knowledge which can be structured to perform
dedicated computational processes within a more
complex system.
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Each agent consists of two entities. The
internal entity addresses the tasks that are
assigned to the agent. Tasks refer to design
requirements associated with the corresponding
concurrency attributes. Internal entity includes
the knowledge required to perform the tasks, the
inference mechanisms necessary to represent that
knowledge, and the means of communication
necessary for the agent to act with the outside
world. The external entity is a planning one in
its nature. It includes the model of the
environment in which the agent operates. This
model contains the abilities of the given agent
as well as other agents present in the system,
and relationships between agents. Internal
entity performs the tasks that the agent is able
to solve itself. The external one acts as an
intelligent planner that determines how the tasks
may be broken down (if possible and necessary),
distributed to other agents, and integrated.
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Agents are grouped into worlds, and each agent
may be a member of many worlds simultaneously.
Agents can communicate either directly or
indirectly (through other agents), and the mode
of communication may differ depending on its
importance. Next Figure depicts grouping and
links between agents.
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Communication links and worlds of agents
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Incorporation of knowledge Each agent
includes knowledge describing its view of the
system from the concurrency perspective. Global
concurrency satisfaction knowledge (global
knowledge) includes ways of decomposing
concurrency problems and coordinating the
integration of results. In other words this
knowledge plans the imposition of concurrency.
Concurrency attribute knowledge describes agents
(or worlds) capable of performing tasks specified
in the global plan for concurrency satisfaction.
Agent knowledge includes the rules of interaction
with other agents during the distribution
process. Hierarchical knowledge describes the
authority of an agent over other agents. In many
cases an agent knowledge may be incomplete and in
contradiction with pieces of knowledge associated
with other agents.
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Incorporation of constraints The environment
of a distributed concurrency problem solver and
knowledge within each agent is represented by
constraints and relaxations. Constraint based
representation for all knowledge makes it
understandable and easy to organize. Relaxations
make for easy selection of alternatives when
constraints cannot be satisfied.
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Through the use of constraint based
representation, an overall problem of concurrency
satisfaction can be decomposed among a number of
agents. Each agent is given a certain amount of
knowledge and agents can negotiate to relax
opposing constraints. Relaxations are used to
solve the problem of the best satisfaction of a
set of constraints according to what is known as
constraint directed reasoning.
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Concurrency requests
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The impact of design decisions at various stages
of the system design process on satisfaction of
different concurrency attributes is not well
understood. Besides, there is no methodology
developed that offers a comprehensive set of
tools for a system analyst to support concurrency
evaluation process and to represent concurrency
related knowledge. On the other hand there is a
big demand for such research in the industry.
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• Recognizing this demand, in this Chapter a
  conceptual architecture was presented in which
  knowledge necessary for concurrency satisfaction
  planning and coordinating activities among
  multiple concurrency agents can be expressed in
  terms of constraints. Such a representation has
  the following advantages
• manipulation of such a knowledge is easy,
• constraint relaxation makes for easy selection of
  alternatives when constraints cannot be
  satisfied,
• a single representation of all knowledge makes it
  easily organized,
• entire concurrent design process can be
  represented using constraints and relaxations.

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DEDUCTION GRAPHS FOR CONCURRENCY
SATISFACTION Introduction to concurrency
satisfaction problem Introduction of various
life-cycle attributes in various stages of
product design is termed concurrency
satisfaction. Concurrency set is a collection of
attributes (manufacturability, serviceability,
etc.) necessary to achieve concurrency.
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This Chapter discusses an approach to plan an
optimal policy to expand concurrency sets in such
a way that the desired concurrency level is
confidently addressed by a designer during the
design process undertaken in a concurrent
environment. The presented approach is based on
deduction graphs and the optimal concurrency plan
is arrived at by applying a 0-1 integer
programming technique.
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For any design undertaken in a concurrent
environment, there is a concurrency set of
attributes necessary to achieve satisfactory
concurrency level. The attributes relate to
various agents influencing the design process
modelled as multiagent system. Designer may want
to plan the development of concurrency set in
such a way that it covers all attributes desired
by a given design.
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The planning process usually starts at the level
of the set of concurrency attributes that have
already been acquired and covers the optimal set
expansion. This concept of expanding the
concurrency set is similar to what is known in
the literature as the problem of competence level
for satisfactory solution of a given decision
problem.
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For the purpose of this Section let us consider
the following three sets of concurrency
attributes for a particular design (D). Adequate
concurrency set (A_d) is a set of attributes
needed for D. Acquired set (A_c) contains
attributes already satisfied in design D. Global
concurrency set (G_l) is a set of all attributes
related to the domain of design D including A_c
and A_d. Please note that, generally, G_l is not
equal to A_d. The planning problem becomes as
follows what is the optimal (minimum cost or
minimum time) expansion way in G_l from A_c to
A_d.
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For product design, the concurrency attributes
usually include the following a1 aesthetics
attribute that considers such design factors as
shape, size, colour, finish, texture, styling,
and social significance, a2 capacity with such
factors as size, force, movement, direction, and
speed, a3 disposability influenced by the
material factor, a4 durability with design
factors of corrosion, humidity, strength,
moisture, and abuse, a5 ergonomics with such
factors as operating height, operating comfort,
lighting, shape compatibility, type of operation,
noise, heat, cold, controls, monitoring devices,
and human size, a6 interchangeability with
factors of rapidity, accuracy, and modules, a7
maintainability with factors of continuous,
regular, sporadic, none, ease of inspection, ease
of repair, life cycle, ease of part replacement,
and availability of parts, a8 marketability
influenced by factors of marketing mix, target
customers, product differentiation, product
quality, product quantity, market share, and
price,
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a9 performance considered with the factors of
force, velocity, acceleration, pressure, energy,
and handling comfort, a10 transportability
described by the factors of lift, orientation,
size, packaging, maximum dimensions, maximum
weight, and storage, a11 producibility
influenced by factors of tolerances, surface,
roughness, dimensions, structure, stress, level,
geometry, size, height, diameter, space
requirements, kinematics, forces, load,
deformation, stiffness, elasticity, resonance,
energy, pressure, temperature, and
operation, a12 reliability with factors of
repeatability, measures of availability, duration
of downtime, and failures characteristics, a13
safety with noise, stability, illumination,
protection systems, operational safety,
environmental safety, edges, warning mechanisms,
magnetic field, and pinch points, a14
schedulability influenced by factors of flow
time, idle time, completion time, delivery dates,
capacity, machine utilisation time, a15
serviceability with factors of ease of repair,
time to service, and time to respond to
service, a16 simplicity considering factors of
technology, manufacture, self-maintenance, and
use, a17 testability with factors of ease of
inspection, built-in tests, and fault
characteristics.
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Directed graph G1 of the sequences of
concurrency attributes introduction
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minz2.5y(a1,a16)4.7y(a3,a11)4y(a3,a14)y(a3,a16
)3y(a5,a11) y(a5,a14)y(a11,a16)y(a14,a11)y(a1
6,a5)2y(a16,a14)
subject to (i) all y(i,j) and xi are 0-1
integers, (ii) xa5 xa11 xa16 1, (iii) xa5
? y(a16,a5), xa11 ? y(a3,a11)y(a14,a11)y(a5,a11
), xa14 ? y(a3,a14)y(a16,a14)y(a5,a14), xa16
? y(a1,a16)y(a3,a16)y(a11,a16), (iv) xa1 ?
y(a1,a16) 3xa3 ? y(a3,a11)ya3,a14)y(a3,a16), 3
xa5 ? (y(a16,a5))(y(a5,a14)y(a5,a11)), 4xa11 ?
(y(a3,a11)y(a14,a11)y(a5,a11))(y(a11,a16)), 4x
a14 ? (y(a5,a14)y(a16,a14)y(a3,a14))(y(a14,a11)
), 5xa16 ? (y(a1,a16)y(a3,a16)y(a11,a16))(y(a1
6,a14)y(a16,a5)).
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By applying any mathematical programming package
one can see that the solution to the above is
given as y(a3,a16) y(a16,a5) y(a5,a14)
y(a14,a11) 1. The resulting optimal deduction
graph is shown in Figure below.
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Compound concurrency attributes
Multilevel concurrency satisfaction
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PLANNING IN CONCURRENT ENVIRONMENT
Although CE offers considerable reductions in
both time and money as well as increases in
product and process quality to an organisation,
the maximum benefit is only likely to be attained
through focusing on the effective planning of the
design process.
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There exists a number of definitions for
planning, including the following Planning can
be considered to be a system of decision making,
goal setting, and task allocation whose main aim
is to satisfy a number of constraints. From an
organisational viewpoint these may be to minimise
cost, time and risk. Planning can be defined as
the predetermination of a course of action aimed
at achieving some goal. Thinking about the
consequences of actions before being forced to
experience them is the essential part of
planning the result of such thinking is a plan,
and the most important part of a plan is the part
that specifies what to do next.
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• The full cycle of distributed planning can be
  thought to consist of
• Plan Generation,
• Plan Decomposition,
• Plan Distribution, and
• Plan Integration
• The execution of this cycle of Generation,
  Decomposition, Distribution, and Integration
  (GDDI) follows a common planning method whereby a
  complex problem is first reduced to a number of
  simpler problems. These simpler problems are then
  solved and the information obtained from their
  solution is used to solve the parent problem.

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Planning support
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Product development costs in different phases
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Blackboard based planning architecture The
basis for an intelligent decision support system
for design process planning within a Concurrent
Engineering (CE) environment is the efficient
utilisation and coordination of planning
knowledge that resides within computerised
workgroups of multidisciplinary experts. A
systems approach may be taken to derive,
represent and utilise the many models of
reasoning that might support a human-centric view
of planning in a distributed environment. The
blackboard database (BB) provides a suitable
framework for utilising these models in a
structured manner by representing the planning
problem as a loosely coupled hierarchy of partial
problems along with the knowledge needed to
progressively solve different parts of this
problem. This Section discusses such a BB system
which is intended to provide the ability to
experiment with various control and domain
strategies in order to yield insight into more
developed and intelligent methods to assist
humans in planning the CE design process.
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The Blackboard Database (BB) is a promising
framework for development of a computerised tool
for planning support that would enable the
strategies, behaviours and reasoning that are
used to apply knowledge to solve complex problems
such as the CE design process planning
problem. The BB also provides the capability to
manipulate the order and duration in which
selected strategies are implemented in
determining their effectiveness in promoting a
solution. The blackboard database is a problem
solving system based on the metaphor of human
experts who cooperate by entering partial
solutions to the current problem onto a physical
blackboard . Each expert contributes its own
specialised knowledge specifically tailored to
solve one aspect of the overall problem. This
provides the flexibility to approach the problem
by applying as many sources of knowledge that are
appropriate and to experiment with different
reasoning strategies.
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CONCURRENCY IMPLEMENTATION Transition from
Sequential to Concurrent Philosophy
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STEP 0. Obtain the commitment from top
management down for a long-term, systems-type
outlook for the business as a whole and the
design activity in particular. This philosophical
realignment must percolate through the entire
organisation and embrace a life-cycle view of the
companys products. STEP 1. Inform, train and
involve all staff from the very beginning of the
implementation process. STEP 2. Review current
company systems, and design methods. Take the
opportunity of discarding worthless procedures
and integrating useful ones. STEP 3. Plan and set
goals based on the CE objectives. STEP
4. Implement design teams with emphasis on
DFX. STEP 5. Upgrade support infrastructure, in
particular computers, databases and
communications in consultation with the design
teams. STEP 6. Introduce concurrency. STEP
7. Monitor and review progress, not just in
activity but also in time. Compare to the formal
plans of Step Three and to other similar
companies.
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Implementing concurrency for environmental
protection Clearly, environmental
protection today has to deal with enormous
challenges and issues related to our real and
virtual environments characterised mainly by
uncertainties, dangerous changes, hazardous
materials, contamination, imprecision, and
novelty of internet just to name a few.
Engineering, operations research, management
science and information technologies race to
help people to use scientific processes to
preserve the quality of human life in such
environments. Concurrent engineering philosophy
seems to be one of the leaders in this
spectacularly exciting race to help to create a
better environmental future for our planet.
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Commercial and industrial waste stream
composition major components
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• In a wholesome view of a product's life cycle,
  clear objectives, including potential
  environmental impact, are necessary at the
  conceptual stage. To prevent and correct
  environmental impact life cycle analysis must act
  hand in hand with good decision making at the
  design stage of a product. Hence, a new design
  paradigm arises Design for Environment (DfE).
  There are three main goals to DfE
• Minimise the use of non-renewable sources.
• Effectively manage renewable resources.
• Minimise toxic releases to the environment.

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In terms of practical aims this means
designing to minimise environmental affects. That
is, to design products whilst considering the
following environmental attributes Ease of
Disassembly Ease of Reuseability Ease of
Recyclability Ease of Remanufacturing Durability
Maintainability Energy Consumption Product
Take Back
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• Ease of Disassembly.
• Design for Disassembly (DfD) There are a number
  of principles that can be followed to ensure ease
  of disassembly. These include
• Consolidate parts and minimise the number of
  components.
• Reduce the number of assembly operations
• Avoid chemical bonds
• Try to avoid composite materials
• Use quick release snap fittings wherever
  possible
• Eliminate or avoid secondary coatings, finishes
  and platings

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Energy Consumption. The less energy a
product requires throughout its life cycle the
better the product is for the environment. Energy
consumed by equipment and appliances is a major
source of greenhouse gas emissions. For example,
these emissions are responsible for more than a
quarter of net greenhouse gas emissions in
Australia (excluding land use change and
forestry). Consequently, improved energy
efficiency of appliances and equipment is a key
objective for DfE.
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Product Take Back. In the future it seems
likely that manufacturers will become responsible
for the ultimate disposal of their product. To
some extent this is already occurring in todays
industry. In Europe, car manufacturers are
investigating methods for recycling scrap
automobiles. Strict environmental recovery laws
(proposed, but not yet implemented) coupled with
declining landfill space have caused European car
manufacturers to take a new look at recycling,
their contributions to the process and ultimate
responsibility for its implementation.
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BMW has opened a pilot recycling plant in
Landshut, Germany, to determine just what it will
take to dismantle its vehicles and recover their
materials on a large scale basis. The company
plans to use the information it gains from the
Landshut program to ease the disassembly and
recovery of future BMW automobiles, and pinpoint
environmentally friendly materials.
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• In trying to generalise, the following
  suggestions may help to ensure that industries in
  any place in the world become more
  environmentally conscious
• Increase the landfill costs
• Promote the cost savings of DfE
• Provide tax benefits for Environmental Products
• Educate people
• Promote increased durability
• Legislate product labelling
• Review Restrictions
• Government Projects