abstraction:
(1) The extraction of essential information relevant to a particular purpose.
(2) The essential information thus selected.
acceptance test: See system acceptance test.
access:
(1) A flow of information to or from a data store.
(2) To store information in or retrieve it from a data store.
actor: A person, organization, or system in the environment which sends a message (input) to the system or receives a message (output) from the system.
aggregate: In an aggregation, the class representing the whole.
aggregation:
(1) A process of assembling a system using a set of elementary components.
(2) An association between classes representing a part-to-whole relationship in which the parts and the whole may exist independently and in which a single part may be associated with more than one whole at the same time.
algorithm: The step-by-step specification of the operations or actions which accomplish a transformation.
alias: An alternate name for an item; a synonym.
alternative (course of action): In an expanded use case description, a conditional action of the system which differs from the typical flow of events.
analysis: The process of determining the structure of an object or system; decomposition. (See systems analysis.)
application layer: The layer of information system architecture which carries out the operations in the business or application domain.
application program: Software which causes general-purpose hardware to carry out transformations required by users.
arc: A component of a network which connects two nodes.
architectural baseline: A component of a network which connects two nodes.
artifact:
(1) An object or system devised by human beings.
(2) A work product or deliverable in the system development process.
association:
(1) A significant connection between problem-domain concepts or between classes.
(2) A connection between use cases.
association concept: A concept whose existence depends on an association between other problem-domain concepts.
attribute: A named characteristic of an object which may take on a value.
automation boundary: A boundary which partitions an information processing system into automated and manual portions.
beneficial user: A person who has no direct contact with an automated information processing system but who provides system input or receives system output.
break-even point: The time at which the present value of the net benefits of a project equals the present value of the cost of the project.
brightness: See value.
business event: A system-level event in a business problem domain.
button: An input device which initiates an action.
channel: A generic hardware component whose function is to transport data.
chroma: Saturation; the position of a color on a scale from its weakest to its most vivid variant. It is related to the proportion of white light mixed with light of the dominant wavelength.
class: A group of objects which have an identical set of attributes and an identical set of behaviors.
client (client/server system): A component of a client/server system which requests services from another component.
client (object): An object which sends a message to a server object.
client/server system: An information processing system consisting of clients and servers connected by a communication network. The clients request services from one or more servers.
closure: The Gestalt principle that visual elements are grouped to form simple, closed figures.
cohesion: A measure of how strongly related and focused the responsibilities of a class are.
collaboration: The fulfillment of a responsibility by two or more objects through client/server relationships.
collaboration diagram: An interaction diagram showing the messages between interacting objects and classes as a network model.
command feedback: A message from a command interpreter indicating that a command just entered has been recognized and accepted or that there is an error in its syntax.
command interpreter: A component of an interactive system which assembles (parses) input primitives into commands.
command language: A style of interaction at the user interface in which the user specifies the execution of a series of tasks without being prompted.
common motion: The Gestalt principle that visual elements are grouped when they move together.
component: In a composition, the class representing one of the parts.
composite: In a composition, a class representing the whole.
composition:
(1) (Of a system input or output) Its content (data elements) and structure (how they are organized).
(2) An association between classes representing a whole-to-part relationship in which the parts may belong to only one whole at a time and the whole does not exist without its parts.
computer aided software engineering (CASE): Software for maintaining interrelated models of an information processing system during the development process.
concept: A person, idea, or thing in the problem domain which is significant for an information system.
conceptual class: A UML term for a constituent of a class diagram. (See concept.)
constituent: In an aggregation, a class representing one of the parts.
constraint: A condition or requirement which must be satisfied (by a proposed problem solution or system design) for the system to be acceptable.
container: A generic hardware component whose function is to store data.
context diagram: A diagram of a system, its environment, and their interactions. More specifically, it is a diagram showing the system as a single object, all its inputs and outputs, the actors who provide the inputs, and the actors who receive the outputs.
continuation: The Gestalt principle that visual elements are grouped to preserve smooth continuity rather than abrupt change.
contract: A description of a behavior which a system component commits itself to carry out; a commitment by the receiver of a message to satisfy the postconditions of an operation if the sender of the message makes sure that the preconditions of the operation are satisfied.
control flow: Information which activates or terminates the execution of an operation or which controls the sequence of execution of the procedure for the operation.
coupling: A measure of how strongly one class is connected to, has knowledge of, or relies on other classes.
Creator pattern: A pattern which assigns the responsibility of requesting a class to create a new object — i.e., which assigns the responsibility of sending a create message.
criterion (pl. criteria): A measurable or observable factor used to compare alternatives.
critical path model: A network model for project planning and scheduling. It shows sequential dependencies between activities and which activities cannot be delayed without delaying the entire project.
data base: A systematically partitioned, reusable, integrated collection of data which can be shared by many users.
database management system: The computer system software which manages a data base, providing for logical and physical data independence, controlling redundancy, and enforcing integrity constraints, privacy, and security.
data capture device: Hardware which transforms automated system inputs from human-readable form to machine-readable form.
data element: A data structure primitive; an item of information which does not require any decomposition in the system of which it is a part.
data flow: A movement of application-specific information within a system or across the system boundary.
data type: The UML term for the description of an attribute of a class. Data types are always either primitive data types or value objects.
design:
(1) A process which creates descriptions of a newly devised artifact.
(2) The product of the design process — a description which is sufficiently complete and detailed to assure that the artifact can be built.
design class diagram: A class diagram which shows attributes, operations, and navigability.
design sequence diagram: A sequence diagram which shows interactions of classes within the system.
device driver (handler): Software which controls an input or output device.
device feedback: A message from a device driver which displays or tracks input primitives.
direct manipulation: A style of interaction at the user interface in which the user manipulates directly objects of interest in the display.
discipline: In the Rational Unified Process, a sequence of activities which produce an observable result of value to an actor (formerly known as workflow).
display: An output device, either in general or one which produces an image.
domain model: An analysis model which represents real-world concepts in a problem domain. A domain model is a static model which shows concepts in the problem domain, their attributes, and associations among them.
economic feasibility: The feasibility of a project based on financial criteria.
encapsulation: Using an interface to protect an object’s internal attributes and behaviors from external access.
environment (of a system): Whatever lies outside the system; often something outside a system which affects or interacts with the system.
ergonomics: The discipline which studies the human factors involved in the design of useful objects, especially in the workplace.
essential:
(1) A model or model component which avoids specifying the technology with which a system is or will be implemented.
(2) A necessary system requirement or component.
event: An occurrence which takes place at a specific time and initiates or triggers a predetermined response from a system.
event analysis: A technique for systems analysis which considers the purpose of an entire information processing system to be responding to a selected set of occurrences in the system’s environment.
event flow: A signal which notifies a system that a particular event has occurred.
expanded use case narrative: A detailed use case narrative, including a typical flow of events, exceptions, and pre- and postconditions.
expert pattern: A pattern which assigns a responsibility to the object which has the attributes needed to carry out the responsibility.
‹‹extends››: A conditional association between use cases such that the extension augments the use case which it extends.
external event: An event which occurs outside the system boundary.
façade (controller): An object which coordinates the work of the objects in the application layer and serves as an interface to the presentation layer.
Façade pattern: A pattern which assigns to a single object representing the system as a whole the responsibility for receiving messages from an initiating actor.
feasibility report: The product of a feasibility study (the activity of making the business case, containing both technical and management guidelines for a system development project, including a summary of system alternatives).
feasible: Satisfying all the constraints on a system.
figure/ground segregation: The perception of some visual elements (the figure or foreground) as being in front of or separate from others (the background).
flow of events: The part of a use case narrative which presents the sequence of actions of the actors and the corresponding responses of the system.
font (printing): A complete assortment of type in one face and size.
font (software): A complete assortment of characters of one design in many faces and sizes.
form fill-in: A style of interaction at the user interface in which the user sees a display of related fields, moves a cursor among the fields, and enters data where desired.
future value: The value of a benefit or cost incurred at a future time.
Gantt chart: A horizontal bar chart showing the scheduling of project activities or tasks.
generalization-specialization: A hierarchical construct in which every instance of a subtype is also an instance of its supertype. Subtypes share (or inherit) the attributes and operations of the supertype.
‹‹generalizes››: An association between use cases which implies that the child use case contains all the attributes, sequences of behavior, and extensions of the parent use case.
Gestalt principles: Principles of visual perception, which stress the unity of visual shapes and patterns.
Gestalt theorists: A group of early—20th-century psychologists who studied perception, including Koehler, Koffka, and Wertheimer.
global visibility: A type of visibility in which an object is obtained from a class by the object requiring visibility to it.
guard: A condition or constraint.
hands-on user: A person who interacts directly with the data capture and data display devices for an automated information processing system.
hierarchy: A system structure in which every system component except the one at the top is subordinate to exactly one immediate superordinate.
hue: A color as perceived. It is related to the dominant wavelength of the light.
human factors: See ergonomics.
icon: A pictorial symbol.
‹‹includes››: An unconditional association between use cases such that the included use case always occurs whenever the use case which includes it occurs.
infeasible: Not feasible; failing to satisfy one of the constraints on a problem or system.
inheritance: The ability of a subclass to have all the attributes and operations of its superclass.
initiating actor: An actor who initiates a use case.
instance: A specific member of a class or an individual occurrence of an association.
interaction diagram: A dynamic model shown in a diagram which depicts the messages between objects or classes in a program.
interactive system: A system in which the user interface is event-driven; the user and the computer communicate through a dialogue.
interface:
(1) A shared boundary.
(2) To connect or be connected.
(3) A connection or interaction between two components or systems.
internal event: An event which occurs inside the system boundary.
iteration:
(1) A control structure for an operation: the process of repeatedly executing a given sequence of programming language statements until a given condition is met or while a given condition is true.
(2) A single execution of a loop.
Joint Application Development (JAD): A process for obtaining agreement on critical decisions about system requirements and design during an intensive workshop for all the relevant users and developers.
Law of Demeter: A design principle which states that a client should give its server the responsibility for collaborating with other objects.
linearity (of a display): A measurement of whether straight lines appear straight.
link: An instance of an association.
local visibility: A type of visibility in which an object is obtained locally by capturing an object returned from a message.
man-machine boundary: The automation boundary.
menu: A list from which a user selects the desired action.
menu selection: A style of interaction at the user interface which allows the user to choose an action from a list of alternatives displayed on the screen.
message: A request from one object to a second object to carry out a behavior or execute an operation belonging to the second object.
method:
(1) An organized process for accomplishing a task.
(2) (In the UML) A specific implementation of or an algorithm for an operation.
milestone: The completion of a phase of system development. It is marked by the delivery of a defined set of artifacts (models or other work products).
model: An abstraction or representation of an object or system.
Model-View Separation pattern: A pattern which states that objects in the application layer should not send messages directly to objects in the presentation layer.
multiplicity: The number of instances of a concept or class which can be associated with one instance of another concept or class.
natural language (interaction style): A style of interaction at the user interface in which the user controls the interaction in a natural language, such as English.
navigability: The ability of a client object to know the identity of a server object with which it collaborates. (Also known as visibility.)
net present value: The present value of a benefit minus the present value of a cost incurred at the same time.
network: A structure comprising a set of nodes connected by arcs.
node: A point within a network.
object: The basic structural component of object-oriented software.
on-line system: A system in which each data flow entering the automated portion is processed as soon as it is received.
operation: A service which can be requested from an object; an implementation of or an algorithm for a procedure.
organizational feasibility: The feasibility of a project based on the politics and culture of the using organization.
package: A set of use cases, objects, or classes comprising a system or subsystem.
parameters (of a message): The data elements transmitted as part of the message.
parameter visibility: A type of visibility in which an object is provided by a message as a parameter.
participating actor: An actor who is involved in a use case but does not initiate it.
pattern: A named statement of a design problem together with its solution.
persistence: The need for an object to continue in existence for a long time.
pixel: A point in a raster display.
phase: In the Rational Unified Process, one of four sequential subdivisions of the system development process. Each ends with the delivery of a set of artifacts and a decision about whether to continue to the next phase or to terminate the project.
plotter: An output device which produces drawings.
polymorphism: The ability of objects in different classes to respond differently to messages of the same name.
postcondition: A condition which states the required effect of an operation on a system.
precondition: A condition which must be true before an operation or use case can be performed successfully.
presentation layer: The layer of information system architecture which manages the user interface, transporting data to and from the application layer.
present value: The value of a future cost or benefit after discounting it for the time value of money.
primitive: An elementary component of a system or language — one which is not decomposed further.
primitive data type: A data type which can be directly represented in computer hardware.
private (attribute or operation): An attribute or operation which is available only from within an object and cannot be accessed by other objects.
prototype: A partial or limited working version of a system.
proximity: The Gestalt principle that visual elements are grouped when they are close to each other.
public (attribute or operation): An attribute or operation which can be accessed by other objects.
qualified association: An association which uses a qualifier at one end to select one or a subset of instances on the other end.
qualifier: An attribute of a class which has a unique value for each object in the class.
quality assurance: Procedures and techniques for minimizing defects and maximizing the quality of a product or system.
random-scan display: A vector display.
raster display: A display organized as a grid of points (pixels).
Rational Unified Process: A system development process for object-oriented software created by Jacobson, Booch, and Rumbaugh and their colleagues at Rational Software Corporation. (Also known as the Unified Process.)
real-time system: A computer system which processes data according to time requirements imposed by an outside process.
real use case narrative: A use case narrative which includes details of the implementing technology.
reference object: An object whose unique identity is meaningful.
reference visibility: A type of visibility in which the client object has a pointer or reference to the server object.
relational data base: A data base structured as a set of tables.
requirement:
(1) A condition or capability needed by a user to solve a problem or achieve an objective.
(2) A condition or capability which must be met by a system or system component to satisfy a contract, standard, specification, or other formal document.
requirements specification: A document produced during systems analysis containing the requirements for a new system.
resolution (of a display): The number of points per inch or other unit of measure which can be displayed.
resource feasibility: The feasibility of a project based on the availability of the required people, materials, equipment, and other resources.
response: What a system does when an event occurs.
responsibility: An obligation of an object to provide services to other objects.
responsible user: A low- to middle-level manager with direct day-to-day responsibility for the business functions supported by an information processing system.
return on investment: The ratio of the overall net present value of a project to the net present value of all the costs.
risk: An uncertainty which has a significant probability of preventing the successful completion of a project milestone.
saturation: See chroma.
scenario: A description of a single occurrence or instance of a use case.
schedule feasibility: The feasibility of a project based on whether the project can be completed in time to meet the business requirements of its users.
selection feedback: A message indicating which objects from the data base have been selected in preparation for or as the result of the execution of the command.
semantic feedback: A message indicating to the user that the operation requested has been completed.
sequence diagram: An interaction diagram which shows the messages between interacting objects and classes in a fence format.
server (client/server system): A component of a client/server system which provides services to another component.
server (object): An object which receives a message from a client object.
signature: A complete definition of the message associated with an operation. It consists of an access specification, the name of the operation the names and data types of the parameters, and the name and type of the object or value returned.
similarity: The Gestalt principle that visual elements are grouped when they are similar to each other.
simulation: The use of a model, often a working model, to represent a system or its behavior.
Singleton pattern: A design pattern which provides a class with a single object; used to provide global visibility or a controlled interface.
software engineering: The discipline concerned with the development of computer software.
special requirement: A system requirement which addresses aspects other than actions of the system, such as response time and reliability.
state: The condition of a system or process between events.
state transition diagram: A network model of a finite-state machine, showing its legal states and the transitions between them.
stimulus: A message or signal which reports the occurrence of an event and triggers a system to respond.
storage layer: The layer of information system architecture which manages the data base, providing access to the data from the application layer.
subclass: A class in a generalization-specialization hierarchy. Its objects have all the attributes and all the operations of its superclass.
subsystem boundary: The limit dividing a subsystem from the rest of a system.
superclass: A class in a generalization-specialization hierarchy. It is the parent of its subclasses.
synthesis: The creation of a whole from components.
system: An interrelated set of components which are viewed as a whole.
system acceptance test: A test of a completed system to determine whether it meets the stated system requirements.
system architecture: The structure of the system; the set of significant decisions about what the software components are and how they are to be organized.
system boundary: The limit dividing the interior of the system from what is outside the system.
system design::
(1) The process of defining the structure and components of a system which satisfies the specified users’ requirements.
(2) The result of the system design process; a description of a system, which satisfies the specified requirements and that is adequate for constructing the system.
system development process: A conceptual framework for understanding and managing the activities involved in information system development and use.
system input: A message or information flow which crosses the system boundary to enter a system.
system model: An abstraction of a real-world system which shows the significant components and their relationships. This abstraction is often used to study and predict the behavior or performance of the system.
system operation: An operation which a system carries out in response to a system input.
system operation contract: A description of the changes in the overall state of a system when a system operation is carried out.
system output: A message or information flow which crosses the system boundary to leave a system.
system owner: A high-level manager and decision maker for the business area supported by an information processing system.
systems analysis: The process of studying user needs to arrive at a definition of system or software requirements.
system sequence diagram: A type of sequence diagram which shows only the interactions between a system and its actors.
technical feasibility: The feasibility of a project in terms of its ability to be constructed.
temporal event: An event which occurs at a prespecified time.
three-tier system architecture: A system architecture consisting of a presentation layer, an application (or business) layer, and a storage layer.
timebox: A limited period of time for accomplishing a specified task or tasks.
transaction: A stimulus which triggers a response from a system. Any element of data, control, signal, event, or change of state which causes, triggers, or initiates some action or sequence of actions.
transition: A change from one state to another.
UML: See Unified Modeling Language.
Unified Modeling Language (UML): A standard notation for describing and modeling object-oriented systems.
Unified Process: See Rational Unified Process.
use case: The sequence of actions which occur when an actor uses a system to complete a process.
use case diagram: A graphical model which shows the use cases of a system in relation to the actors in its environment.
use case narrative: A narrative presenting the sequence of internal actions by which the system responds to actions of an actor.
use case scenario: An instance of a use case.
user interface: The hardware and software at the automation boundary.
value (color): Brightness; intensity; the position of a color on a gray scale — that is, its lightness or darkness independent of the particular hue. Value is related to the amount of luminous energy in the light.
value object: An object whose unique identity is not meaningful.
visibility: The ability of a client object to know the identity of a server object with which it collaborates. (Also known as navigability.)
walkthrough: A group review of a work product for the purpose of judging its completeness, correctness, consistency, and adherence to standards.
window navigation diagram: A model of the navigation paths between windows or screens in a workstation display or between web pages.
workflow: See discipline.