OSLC Estimation and Measurement Service (EMS) Vocabulary
The namespace URI for this vocabulary is:
http://open-services.net/ns/ems#
This vocabulary defines estimation and measurement resources and a service for managing them in projects.
Some terms of this vocabulary have been finalized for use by
OSLC Performance Monitoring 2.0.
Label: OSLC EMS Vocabulary
This document lists the RDF classes, properties, and individuals that are defined by this vocabulary. Following W3C best practices, this vocabulary is available as HTML (this document) and as RDF source.
More details about how this page was generated, and other related material, can be found in OSLC Core URI Naming Guidance.
Classes defined by this vocabulary(50):
Baseline, BaselineList, CdfPoint, CumulativeDistributionFunction, Dimension, DimensionCell, DimensionColumn, DimensionMember, EffortMetric, Estimate, EstimateList, Fact, FactDistribution, FactDistributionTable, FactTable, FinancialMetric, Format, Grain, Head, Map, Mapping, Measure, MeasureCell, MeasureColumn, MeasureDistribution, MeasureDistributionCell, Measurement, MeasurementList, Metric, NormalDistribution, PointEstimate, PoissonDistribution, ProbabilityDistribution, ProcessMetric, ProductivityMetric, Project, ProjectList, Quantile, QuantileFunction, ReliabilityMetric, Scenario, ScenarioList, Service, SizeMetric, TimeMetric, TriangularDistribution, UniformDistribution, UnitOfMeasure, WbsFormat, WorkBreakdownStructure
Properties defined by this vocabulary(66):
assumes, assumesTable, assumesWbs, baselineList, cdfPoint, currentBaseline, dimension, dimensionCell, dimensionColumn, dimensionMember, distribution, estimate, estimateList, extendsScenario, fact, from, grain, head, high, inColumn, isActive, isClosed, lambda, low, map, mapping, measureCell, measureColumn, measureDistributionCell, measurementList, memberBaseline, memberEstimate, memberMeasurement, memberProject, memberScenario, metric, mostLikely, mu, numberOfQuantiles, numericValue, observes, observesTable, observesWbs, predicts, predictsTable, predictsWbs, probability, project, projectList, quantile, realProjectId, scale, scenario, scenarioList, seeAlsoEstimation, seeAlsoPerformance, seeAlsoPortfolio, seeAlsoProject, service, tableSource, to, unitOfMeasure, useMap, wbsContent, wbsFormat, wbsSource
Individuals defined by this vocabulary(0):
None.
Prefixes defined in this vocabulary:
Pre-defined standard prefixes:
assumes
ems:assumes is an RDF property.
This property links a scenario to the assumed value for some measure, e.g. duration, size.
The assumed value is a probability distribution.
assumesTable
ems:assumesTable is an RDF property.
This property links a scenario to the assumed value for some fact table of measures, e.g. staffing by week.
The assumed fact table contains probability distributions.
assumesWbs
ems:assumesWbs is an RDF property.
This property links a scenario to the assumed work breakdown structure.
Baseline
ems:Baseline is an RDF class.
A baseline is a set of estimates, based on some scenario, that are used to track the performance of a project.
CdfPoint
ems:CdfPoint is an RDF class.
This class describes a point on the graph of a cumulative probability function.
The cumulative probability at a point is given by
ems:probability.
The cumulative probability MUST be greater than 0 and less than 1.
The measurement value is given by
ems:numericValue.
The probability that a measurement gives a value less than or equal to
the numeric value is equal to the cumulative probability.
cdfPoint
ems:cdfPoint is an RDF property.
This property links a cumulative probability function resource to one or more points on its graph.
CumulativeDistributionFunction
ems:CumulativeDistributionFunction is an RDF class.
A cumulative distribution function (cdf) is a probabilty distribution defined by giving the
cumulative probability at an increasing sequence of measurement values.
The range of possible measurement values may be unbounded.
If a lower bound exists, it is given by ems:low.
If an upper bound exists, it is given by ems:high.
The graph of the cumulative distribution function is given by a set of measurement values
at an increasing sequence of cumulative probabilities between 0 and 1.
The cumulative probability values are given by one or more
ems:cdfPoint properties.
Label: CumulativeDistributionFunction
Dimension
ems:Dimension is an RDF class.
A dimension is some aspect of an aggregated quantity which lets the aggregate be analyzed.
For example, the total effort expended in a project can be analyzed by week or month.
Therefore time
(dimension:Time)
is a dimension of effort
(metric:Effort).
dimensionColumn
ems:dimensionColumn is an RDF property.
This property links the head of a fact table to one or more
ems:DimensionColumn
resources that define dimension columns.
Every fact table MUST have at least one dimension column.
Estimate
ems:Estimate is an RDF class.
An estimate is a probabilistic prediction, based on a scenario, for a set of measurements.
extendsScenario
ems:extendsScenario is an RDF property.
This property links a scenario a base scenario that it extends.
The base scenario contains assumptions that can be included in several other extended scenarios.
fact
ems:fact is an RDF property.
This property links a fact table to its fact rows.
In general, a fact table will have many fact rows.
If the fact table has an
ems:tableSource property,
then the rows of the fact table MUST be a copy of the data values received in the response of
an HTTP GET request of the URL of the remote table source.
FactTable
ems:FactTable is an RDF class.
This class is used to represent fact tables.
Consider the work performed on a project.
Work may be analyzed according to attributes such as who performed the work,
the task or activity that the work accomplished,
when the work was performed, etc.
These attributes are referred to as dimensions.
Work may be quantified by such metrics as its effort in person-hours,
its cost in some currency, its duration in months, its peak staffing, etc.
These quantities are referred to as measures.
The term dimension is used because the measures can be regarded as occupying cells
in a multi-dimensional array (sometimes referred to as a datacube).
It is frequently of interest to summarize the measures along a dimension,
for example given the effort by activity, calculate the total effort for all activities.
Conversely, given the total effort, it may be of interest to see how it is broken down by activity.
In general, set of related measures, analyzed along a set of dimensions may be organized into a
fact table.
Each row of a fact table contains a set of measures (e.g. effort and cost)
for a given combination of dimension values (e.g. activity and month).
This resource MAY contain the actual measurements,
provide a link to the source of the actual measurements,
or contain both a link to the source and a copy of the actual measurements obtained from the source
(i.e. a cached copy of the source).
ems:Format is an RDF class.
A format is a specification of the syntax of an artifact.
from
ems:from is an RDF property.
This property links a mapping to its custom label value.
The value MUST be unique within its enclosing map resource.
Head
ems:Head is an RDF class.
This class defined the columns of a fact table.
A fact table MUST have one or more dimension columns, e.g. date or role,
and one or more measure columns, e.g. cost or effort.
The dimension columns contain dimension values.
Dimension columns SHOULD contain standard dimension values when they exist, e.g. for roles.
The creator of the fact table MAY use custom dimension dimension values and
record how these custom values are mapped to the standard values.
head
ems:head is an RDF property.
This property links a fact table to an
ems:Head resource that
describes the columns of the table.
high
ems:high is an RDF property.
This property gives the high parameter value of a probability distribution.
isActive
ems:isActive is an RDF property.
This boolean property indicates if a scenario is under active consideration.
When a scenario has been ruled out, it is marked as inactive by setting this property to <code>false</code>.
isClosed
ems:isClosed is an RDF property.
This boolean property indicates if the project is closed.
No further activities or measurements are done on closed projects.
The measurements of closed projects can be used to calibrate the estimates for new projects.
When a project is completed and all measurements on it have been performed,
it is marked as closed by setting this property to <code>true</code>.
lambda
ems:lambda is an RDF property.
This property gives the lambda parameter value of a Poission distribution.
low
ems:low is an RDF property.
This property gives the low parameter value of a probability distribution.
Map
ems:Map is an RDF class.
Some key dimensions may define standard dimension member URIs which are used for
data interchange. However, users may wish to use custom values.
This class lets you define how custom values are mapped to standard URIs.
You can include an map resource in the description of a dimension column of a fact table
(see ems:useMap).
We make the simplifying assumption that this mapping is many-to-one, that is,
one or more custom dimension values may be mapped to the same standard dimension value.
A map may contain one or more of these mappings
(see ems:mapping), but each custom dimension value must map to
exactly one standard dimension value.
map
ems:map is an RDF property.
This property links a fact table head to an
ems:Map resource that defines
how custom dimension values are mapped to standard values.
The scope of this mapping is local to the fact table.
Mapping
ems:Mapping is an RDF class.
This class describes a mapping.
A mapping maps some custom string label value for a dimension
(see ems:from) to a dimension member URI which may be a standard
value defined in some vocabulary.
(see ems:to).
mapping
ems:mapping is an RDF property.
This property links a map to a mapping.
A map may have one or more mappings.
Measure
ems:Measure is an RDF class.
A measure, as in the idiom take the measure of,
is the result of observing some numerically quantifiable aspect of a project, system, or thing.
For example, a duration of 12 months or a size of 10 KLOC are measures.
The aspect being measured, e.g. duration or size, is referred to as the metric
and is given by the property ems:metric.
The scale of measurement, e.g. months or KLOC, is referred to as the unit of measure
and is given by the property ems:unitOfMeasure.
The numeric value of an observation, e.g. 12 or 10, is given by the property
ems:numericValue.
measureCell
ems:measureCell is an RDF property.
This property links a fact row to one or more of its measure cells.
measureColumn
ems:measureColumn is an RDF property.
This property links the head of a fact table to one or more
ems:MeasureColumn resources that define measure columns.
Every fact table MUST have at least one measure column.
measureDistributionCell
ems:measureDistributionCell is an RDF property.
This property links a fact distribution row to a measure distribution cell.
Label: measureDistributionCell
Measurement
ems:Measurement is an RDF class.
A measurement is a set of observations of numerically quantifiable aspects of a project, system, or thing.
Metric
ems:Metric is an RDF class.
A metric is a procedure or algorithm for quantifying or measuring some aspect of a thing, system, event, etc.
For example duration is a metric that measures the amount of time an activity takes.
metric
ems:metric is an RDF property.
This property links a measure to its metric.
For example, the measure duration of 12 months has the metric duration.
mostLikely
ems:mostLikely is an RDF property.
This property gives the most likely parameter value of a probability distribution.
mu
ems:mu is an RDF property.
This property gives the mu parameter value of a probability distribution.
NormalDistribution
ems:NormalDistribution is an RDF class.
A normal distribution (also known as a Gaussian distribution
is a probability distribution that naturally arises as the
limit of many random factors. It is symmetric about its mean and has a certain scale.
The mean is given by ems:mu.
Its scale (also known as its standard deviation) is given by
ems:scale.
Label: NormalDistribution
numberOfQuantiles
ems:numberOfQuantiles is an RDF property.
This property gives the number of quantiles parameter value of a probability distribution.
numericValue
ems:numericValue is an RDF property.
This property gives the numeric value of a resource.
For example, the numeric value of the measure duration of 12 months is 12.
The datatype of this property is typically xsd:double.
observes
ems:observes is an RDF property.
This property links a measurement to the observed value of a measure.
In an EMS service, the measurement is a resource of type
ems:Measurement
which may observe zero or more measures.
For example, a measurement at the end of a project may observe a duration of 12 months and a cost of 200,000 USD.
observesTable
ems:observesTable is an RDF property.
This property links a measurement to the observed fact table.
The fact table analyzes the measurement along one or more dimensions.
observesWbs
ems:observesWbs is an RDF property.
This property links a measurement to the observed work breakdown structure.
PoissonDistribution
ems:PoissonDistribution is an RDF class.
A Poisson distribution is a probability distribution that gives the probability
that a given number of events will occur in a fixed time period.
This distribution is completely specified by a single parameter often denoted by the
Greek letter lambda.
Lambda is given by ems:lambda.
Label: PoissonDistribution
predicts
ems:predicts is an RDF property.
This property links an estimate to the predicted value for some measure, e.g. duration, size.
The predicted value is a probability distribution.
predictsTable
ems:predictsTable is an RDF property.
This property links an estimate to the predicted value for some fact table of measures, e.g. staffing by week.
The predicted fact table contains probability distributions.
predictsWbs
ems:predictsWbs is an RDF property.
This property links an estimate to the predicted work breakdown structure.
probability
ems:probability is an RDF property.
This property gives the cumulative probability.
For example, the cumulative probability of the third quartile is 75%.
ProbabilityDistribution
ems:ProbabilityDistribution is an RDF class.
This class describes probability distributions.
A probability distribution gives the likelihood that a measurement of some value
(a random variable)
will fall within some given range.
Probability distributions are used in scenario assumptions
(see ems:assumes) and estimate predictions
(see ems:predicts).
Label: ProbabilityDistribution
ProductivityMetric
ems:ProductivityMetric is an RDF class.
A productivity metric is a metric that measures the rate at which some artifact, such as software, is produced.
For example,
lines of code per unit time
(metric:EslocPerTime) and
team velocity
(metric:TeamVelocity)
are productivity metrics.
Label: ProductivityMetric
Project
ems:Project is an RDF class.
Within the scope of EMS, a project is any activity, system, or thing that can be the subject of a set of measurements.
In practice, a project is often a time-bounded work effort that produces a unique result.
Quantile
ems:Quantile is an RDF class.
This class describes a quantile of a quantile function.
The cumulative probability of a quantile is given by
ems:probability.
The cumulative probability MUST be greater than 0 and less than 1.
The upper limit of the range of measurement values is given by
ems:numericValue.
The lower limit of the range of measurement values is given by
the upper limit of the preceding quantiles.
The probability that a measurement gives a value less than or equal to
the numeric value is equal to the cumulative probability.
quantile
ems:quantile is an RDF property.
This property links a quantile function resource to one or more quantiles.
QuantileFunction
ems:QuantileFunction is an RDF class.
A quantile function is a probability distribution that breaks up a range of values
into quantiles that each have the same probability.
When the number of quantiles is 4, 10, or 100, we refer to them as quartiles,
deciles, and percentiles.
For example, there is a 25% probability that a measurement will fall within any given quartile.
The number of quantiles is given by
ems:numberOfQuantiles.
The number of quantiles MUST be greater than one.
The range of possible measurement values may be unbounded.
If a lower bound exists, it is given by ems:low.
If an upper bound exists, it is given by ems:high.
The graph of the quantile function is given by a set of measurement values that
correspond to the equally spaced cumulative probabilities between 0 and 1.
For example, for quartiles the cumulative probabilities are 25%, 50%, and 75%.
The cumulative probability values are given by one or more
ems:quantile properties.
Label: QuantileDistribution
realProjectId
ems:realProjectId is an RDF property.
This property links a project to an identifier of the project as a real-world object.
scale
ems:scale is an RDF property.
This property gives the scale parameter value of a probability distribution.
This parameter is also known as the standard deviation and is often denoted by
the Greek letter sigma.
Scenario
ems:Scenario is an RDF class.
A scenario is a set of assumptions about how a project will be executed.
These assumptions are used as inputs to estimates.
seeAlsoEstimation
ems:seeAlsoEstimation is an RDF property.
This property links a project to a corresponding resource in an estimation application.
ems:seeAlsoPerformance is an RDF property.
This property links a project to a corresponding resource in a performance management application.
Label: seeAlsoPerformance
seeAlsoPortfolio
ems:seeAlsoPortfolio is an RDF property.
This property links a project to a corresponding resource in a portfolio management application.
seeAlsoProject
ems:seeAlsoProject is an RDF property.
This property links a project to a corresponding resource in a project management application.
Service
ems:Service is an RDF class.
An EMS service hosts and manages a set of resources that describe projects, scenarios, estimates, measurements, and baselines.
Each instance of an service has a set of resource containers that contain resources of a given type.
service
ems:service is an RDF property.
This property is used to link a resource to the EMS service instance that hosts it.
SizeMetric
ems:SizeMetric is an RDF class.
A size metric is a metric that measures the magnitude, volume, bulk, or capability of some artifact such as software.
For example,
lines of code
(metric:Sloc) and
story points
(metric:StoryPoints)
are size metrics.
tableSource
ems:tableSource is an RDF property.
Fact tables contain actual measurements for projects, systems, or things.
In practice, there may be many measurements and they may be updated frequently.
The measurements may be at a finer level of granularity than the estimates,
e.g. a project may estimate total defects found per month,
whereas the actual number found may be collected daily.
Furthermore, these measurements are often collected automatically by software development tools
such as bug tracking systems or source code control systems.
It may therefore be useful to simply refer to the source of the measurements rather than copy
the actual measurements into the EMS service provider,
e.g. a dynamic query on a software tool may generate the fact table on demand.
This property lets you refer to the remote source of the fact table data via a URL.
An HTTP GET request on this URL MUST return an
ems:FactTable resource whose
dcterms:title and
ems:head properties match this resource.
to
ems:to is an RDF property.
This property links a mapping to its dimension member URI.
Many mappings MAY map to the same dimension member URI.
TriangularDistribution
ems:TriangularDistribution is an RDF class.
A triangular distribution is a probability distribution that concentrated between
high and low values, and that linearly rises to and falls from to an
intermediate most likely value.
The low value is given by ems:low.
The most likely value is given by ems:mostLikely.
The high value is given by ems:high.
Label: TriangularDistribution
ems:UniformDistribution is an RDF class.
A uniform distribution is a probability distribution that is evenly spread between
a high and a low value.
The high value is given by ems:high.
The low value is given by ems:low.
Label: UniformDistribution
unitOfMeasure
ems:unitOfMeasure is an RDF property.
This property gives the unit of measure. For example, the measure duration of 12 months has a unit of measure months.
wbsContent
ems:wbsContent is an RDF property.
This property gives the literal XML WBS content of a WBS resource.
This content MUST be in the XML format specified by the WBS resource.
If this property is absent, then ems:wbsSource MUST be present.
If this property and ems:wbsSource are present,
then the value of this property SHOULD be the XML document representation returned in the
HTTP GET response for the link given in ems:wbsSource.
ems:wbsFormat is an RDF property.
This property links a WBS resource to the XML format of its content.
EMS does not define a format for WBS content.
Instead, this property identifies the specification that defines the XML format of the WBS content.
wbsSource
ems:wbsSource is an RDF property.
This property links a WBS resource to a resource that contains the WBS XML content.
This content MUST be in the XML format specified by the WBS resource.
When this link is deferenced using an HTTP GET request, the response MUST be the WBS.
If this property is absent, then the WBS resource MUST have a
ems:wbsContent property.
WorkBreakdownStructure
ems:WorkBreakdownStructure is an RDF class.
This class describes work breakdown structures.
A work breakdown structure (WBS) is a common way to represent the work to be performed in a project.
In EMS, a WBS may be used as an assumption in an scenario,
as a prediction in an estimate, or as an observation in a measurement.
A WBS has a format
(see ems:wbsFormat), and may either include
(see ems:wbsContent) or link to
(see ems:wbsSource) its content.
The included or linked WBS content MUST be in the specified format.
Label: WorkBreakdownStructure
