1991 ACM Classification System:

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The ACM Computing Classification System (1991)

A. General Literature
- A.0 GENERAL
  - Biographies/autobiographies
  - Conference proceedings
  - General literary works (e.g., fiction, plays)
- A.1 INTRODUCTORY AND SURVEY
- A.2 REFERENCE (e.g., dictionaries, encyclopedias, glossaries)
- A.m MISCELLANEOUS
B. Hardware
- B.0 GENERAL
- B.1 CONTROL STRUCTURES AND MICROPROGRAMMING (D.3.2)
  - B.1.0 General
  - B.1.1 Control Design Styles
    - Hardwired control
    - Microprogrammed logic arrays
    - Writable control store
  - B.1.2 Control Structure Performance Analysis and Design Aids
    - Automatic synthesis
    - Formal models
    - Simulation
  - B.1.3 Control Structure Reliability, Testing, and Fault-Tolerance
    - Diagnostics
    - Error-checking
    - Redundant checking
    - Test generation
  - B.1.4 Microprogram Design Aids (D.2.2, D.2.4, D.3.2, D.3.4)
    - Firmware engineering
    - Languages and compilers
    - Machine-independent microcode generation
    - Optimization
    - Verification
  - B.1.5 Microcode Applications
    - Direct data manipulation
    - Firmware support of operating systems/instruction sets
    - Instruction set interpretation
    - Peripheral control
    - Special-purpose
  - B.1.m Miscellaneous
- B.2 ARITHMETIC AND LOGIC STRUCTURES
  - B.2.0 General
  - B.2.1 Design Styles (C.1.1, C.1.2)
    - Calculator
    - Parallel
    - Pipeline
  - B.2.2 Performance Analysis and Design Aids
    - Simulation
    - Verification
    - Worst-case analysis
  - B.2.3 Reliability, Testing, and Fault-Tolerance
    - Diagnostics
    - Error-checking
    - Redundant design
    - Test generation
  - B.2.m Miscellaneous
- B.3 MEMORY STRUCTURES
  - B.3.0 General
  - B.3.1 Unassigned
  - B.3.2 Design Styles (D.4.2)
    - Associative memories
    - Cache memories
    - Interleaved memories
    - Mass storage (e.g., magnetic, optical)
    - Primary memory
    - Sequential-access memory
    - Shared memory
    - Virtual memory
  - B.3.3 Performance Analysis and Design Aids (C.4)
    - Formal models
    - Simulation
    - Worst-case analysis
  - B.3.4 Reliability, Testing, and Fault-Tolerance
    - Diagnostics
    - Error-checking
    - Redundant design
    - Test generation
  - B.3.m Miscellaneous
- B.4 INPUT/OUTPUT AND DATA COMMUNICATIONS
  - B.4.0 General
  - B.4.1 Data Communications Devices
    - Processors
    - Receivers (e.g., voice, data, image)
    - Transmitters
  - B.4.2 Input/Output Devices
    - Channels and controllers
    - Data terminals and printers
    - Image display
    - Voice
  - B.4.3 Interconnections (subsystems)
    - Asynchronous/synchronous operation
    - Fiber optics
    - Interfaces
    - Physical structures (e.g., backplanes, cables, chip carriers)
    - Topology (e.g., bus, point-to-point)
  - B.4.4 Performance Analysis and Design Aids
    - Formal models
    - Simulation
    - Verification
    - Worst-case analysis
  - B.4.5 Reliability, Testing, and Fault-Tolerance
    - Built-in tests
    - Diagnostics
    - Error-checking
    - Hardware reliability
    - Redundant design
    - Test generation
  - B.4.m Miscellaneous
- B.5 REGISTER-TRANSFER-LEVEL IMPLEMENTATION
  - B.5.0 General
  - B.5.1 Design
    - Arithmetic and logic units
    - Control design
    - Data-path design
    - Memory design
    - Styles (e.g., parallel, pipelined, special-purpose)
  - B.5.2 Design Aids
    - Automatic synthesis
    - Hardware description languages
    - Optimization
    - Simulation
    - Verification
  - B.5.3 Reliability and Testing
    - Built-in tests
    - Error-checking
    - Redundant design
    - Test generation
    - Testability
  - B.5.m Miscellaneous
- B.6 LOGIC DESIGN
  - B.6.0 General
  - B.6.1 Design Styles
    - Cellular arrays and automata
    - Combinational logic
    - Logic arrays
    - Memory control and access
    - Memory used as logic
    - Parallel circuits
    - Sequential circuits
  - B.6.2 Reliability and Testing
    - Built-in tests
    - Error-checking
    - Redundant design
    - Test generation
    - Testability
  - B.6.3 Design Aids
    - Automatic synthesis
    - Hardware description languages
    - Optimization
    - Simulation
    - Switching theory
    - Verification
  - B.6.m Miscellaneous
- B.7 INTEGRATED CIRCUITS
  - B.7.0 General
  - B.7.1 Types and Design Styles
    - Advanced technologies
    - Algorithms implemented in hardware
    - Gate arrays
    - Input/Output circuits
    - Memory technologies
    - Microprocessors and microcomputers
    - Standard cells
    - VLSI (very large scale integration)
  - B.7.2 Design Aids
    - Graphics
    - Layout
    - Placement and routing
    - Simulation
    - Verification
  - B.7.3 Reliability and Testing
    - Built-in tests
    - Error-checking
    - Redundant design
    - Test generation
    - Testability
  - B.7.m Miscellaneous
- B.m MISCELLANEOUS
  - Design management
C. Computer Systems Organization
- C.0 GENERAL
  - Hardware/software interfaces
  - Instruction set design (e.g., RISC, CISC)
  - System architectures
  - Systems specification methodology
- C.1 PROCESSOR ARCHITECTURES
  - C.1.0 General
  - C.1.1 Single Data Stream Architectures
    - Multiple-instruction-stream, single-data-stream processors (MISD)
    - Pipeline processors
    - Single-instruction-stream, single-data-stream processors (SISD)
    - Von Neumann architectures
  - C.1.2 Multiple Data Stream Architectures (Multiprocessors)
    - Array and vector processors
    - Associative processors
    - Connection machines
    - Interconnection architectures (e.g., common bus, multiport memory, crossbar switch)
    - Multiple-instruction-stream, multiple-data-stream processors (MIMD)
    - Parallel processors
    - Pipeline processors
    - Single-instruction-stream, multiple-data-stream processors (SIMD)
  - C.1.3 Other Architecture Styles
    - Adaptable architectures
    - Capability architectures
    - Cellular architecture
    - Data-flow architectures
    - High-level language architectures
    - Neural nets
    - Stack-oriented processors
  - C.1.m Miscellaneous
    - Analog computers
    - Hybrid systems
- C.2 COMPUTER-COMMUNICATION NETWORKS
  - C.2.0 General
    - Data communications
    - Open System Interconnection reference model (OSI)
    - Security and protection
  - C.2.1 Network Architecture and Design
    - Centralized networks
    - Circuit switching networks
    - Distributed networks
    - ISDN (Integrated Services Digital Network)
    - Network communications
    - Network topology
    - Packet networks
    - Store and forward networks
  - C.2.2 Network Protocols
    - Protocol architecture
    - Protocol verification
  - C.2.3 Network Operations
    - Network management
    - Network monitoring
    - Public networks
  - C.2.4 Distributed Systems
    - Distributed applications
    - Distributed databases
    - Network operating systems
  - C.2.5 Local Networks
    - Access schemes
    - Buses
    - Rings
  - C.2.m Miscellaneous
- C.3 SPECIAL-PURPOSE AND APPLICATION-BASED SYSTEMS (J.7)
  - Microprocessor/microcomputer applications
  - Process control systems
  - Real-time systems
  - Signal processing systems
- C.4 PERFORMANCE OF SYSTEMS
  - Design studies
  - Measurement techniques
  - Modeling techniques
  - Performance attributes
  - Reliability, availability, and serviceability
- C.5 COMPUTER SYSTEM IMPLEMENTATION
  - C.5.0 General
  - C.5.1 Large and Medium ("Mainframe") Computers
    - Super (very large) computers
  - C.5.2 Minicomputers
  - C.5.3 Microcomputers
    - Microprocessors
    - Personal computers
    - Workstations
  - C.5.4 VLSI Systems
  - C.5.m Miscellaneous
- C.m MISCELLANEOUS
D. Software
- D.0 GENERAL
- D.1 PROGRAMMING TECHNIQUES (E)
  - D.1.0 General
  - D.1.1 Applicative (Functional) Programming
  - D.1.2 Automatic Programming (I.2.2)
  - D.1.3 Concurrent Programming
    - Distributed programming
    - Parallel programming
  - D.1.4 Sequential Programming
  - D.1.5 Object-oriented Programming
  - D.1.6 Logic Programming
  - D.1.7 Visual Programming
  - D.1.m Miscellaneous
- D.2 SOFTWARE ENGINEERING (K.6.3)
  - D.2.0 General (K.5.1)
    - Protection mechanisms
    - Standards
  - D.2.1 Requirements/Specifications (D.3.1)
    - Languages
    - Methodologies
    - Tools
  - D.2.2 Tools and Techniques
    - Computer-aided software engineering (CASE)
    - Decision tables
    - Flow charts
    - Modules and interfaces
    - Petri nets
    - Programmer workbench
    - Software libraries
    - Structured programming
    - Top-down programming
    - User interfaces
  - D.2.3 Coding
    - Pretty printers
    - Program editors
    - Reentrant code
    - Standards
  - D.2.4 Program Verification (F.3.1)
    - Assertion checkers
    - Correctness proofs
    - Reliability
    - Validation
  - D.2.5 Testing and Debugging
    - Code inspections and walk-throughs
    - Debugging aids
    - Diagnostics
    - Dumps
    - Error handling and recovery
    - Monitors
    - Symbolic execution
    - Test data generators
    - Tracing
  - D.2.6 Programming Environments
    - Interactive
  - D.2.7 Distribution and Maintenance
    - Corrections
    - Documentation
    - Enhancement
    - Extensibility
    - Portability
    - Restructuring
    - Version control
  - D.2.8 Metrics (D.4.8)
    - Complexity measures
    - Performance measures
    - Software science
  - D.2.9 Management (K.6.3, K.6.4)
    - Copyrights
    - Cost estimation
    - Life cycle
    - Productivity
    - Programming teams
    - Software configuration management
    - Software quality assurance (SQA)
    - Time estimation
  - D.2.10 Design
    - Methodologies
    - Representation
  - D.2.m Miscellaneous
    - Rapid prototyping
    - Reusable software
- D.3 PROGRAMMING LANGUAGES
  - D.3.0 General
    - Standards
  - D.3.1 Formal Definitions and Theory (D.2.1, F.3.1, F.3.2, F.4.2, F.4.3)
    - Semantics
    - Syntax
  - D.3.2 Language Classifications
    - Applicative languages
    - Concurrent, distributed, and parallel languages
    - Data-flow languages
    - Design languages
    - Extensible languages
    - Macro and assembly languages
    - Microprogramming languages
    - Nondeterministic languages
    - Nonprocedural languages
    - Object-oriented languages
    - Specialized application languages
    - Very high-level languages
  - D.3.3 Language Constructs and Features (E.2)
    - Abstract data types
    - Concurrent programming structures
    - Control structures
    - Coroutines
    - Data types and structures
    - Dynamic storage management
    - Input/Output
    - Modules, packages
    - Procedures, functions, and subroutines
    - Recursion
  - D.3.4 Processors
    - Code generation
    - Compilers
    - Interpreters
    - Optimization
    - Parsing
    - Preprocessors
    - Run-time environments
    - Translator writing systems and compiler generators
  - D.3.m Miscellaneous
- D.4 OPERATING SYSTEMS (C)
  - D.4.0 General
  - D.4.1 Process Management
    - Concurrency
    - Deadlocks
    - Multiprocessing/multiprogramming
    - Mutual exclusion
    - Scheduling
    - Synchronization
  - D.4.2 Storage Management
    - Allocation/deallocation strategies
    - Distributed memories
    - Main memory
    - Secondary storage
    - Segmentation
    - Storage hierarchies
    - Swapping
    - Virtual memory
  - D.4.3 File Systems Management (E.5)
    - Access methods
    - Directory structures
    - Distributed file systems
    - File organization
    - Maintenance
  - D.4.4 Communications Management (C.2)
    - Buffering
    - Input/Output
    - Message sending
    - Network communication
    - Terminal management
  - D.4.5 Reliability
    - Backup procedures
    - Checkpoint/restart
    - Fault-tolerance
    - Verification
  - D.4.6 Security and Protection (K.6.5)
    - Access controls
    - Authentication
    - Cryptographic controls
    - Information flow controls
    - Invasive software (e.g., viruses, worms, Trojan horses)
    - Security kernels
    - Verification
  - D.4.7 Organization and Design
    - Batch processing systems
    - Distributed systems
    - Hierarchical design
    - Interactive systems
    - Real-time systems and embedded systems
  - D.4.8 Performance (C.4, D.2.8, I.6)
    - Measurements
    - Modeling and prediction
    - Monitors
    - Operational analysis
    - Queueing theory
    - Simulation
    - Stochastic analysis
  - D.4.9 Systems Programs and Utilities
    - Command and control languages
    - Linkers
    - Loaders
    - Window managers
  - D.4.m Miscellaneous
- D.m MISCELLANEOUS
  - Software psychology
E. Data
- E.0 GENERAL
- E.1 DATA STRUCTURES
  - Arrays
  - Graphs
  - Lists
  - Tables
  - Trees
- E.2 DATA STORAGE REPRESENTATIONS
  - Composite structures
  - Contiguous representations
  - Hash-table representations
  - Linked representations
  - Primitive data items
- E.3 DATA ENCRYPTION
  - Data encryption standard (DES)
  - Public key cryptosystems
- E.4 CODING AND INFORMATION THEORY (H.1.1)
  - Data compaction and compression
  - Error control codes
  - Formal models of communication
  - Nonsecret encoding schemes
- E.5 FILES (D.4.3, F.2.2, H.2)
  - Backup/recovery
  - Optimization
  - Organization/structure
  - Sorting/searching
- E.m MISCELLANEOUS
F. Theory of Computation
- F.0 GENERAL
- F.1 COMPUTATION BY ABSTRACT DEVICES
  - F.1.0 General
  - F.1.1 Models of Computation (F.4.1)
    - Automata (e.g., finite, push-down, resource-bounded)
    - Bounded-action devices (e.g., Turing machines, random access machines)
    - Computability theory
    - Relations among models
    - Self-modifying machines (e.g., neural networks)
    - Unbounded-action devices (e.g., cellular automata, circuits, networks of machines)
  - F.1.2 Modes of Computation
    - Alternation and nondetermination
    - Interactive computation
    - Parallelism and concurrency
    - Probabilistic computation
    - Relations among modes
    - Relativized computation
  - F.1.3 Complexity Classes (F.2)
    - Complexity hierarchies
    - Machine-independent complexity
    - Reducibility and completeness
    - Relations among complexity classes
    - Relations among complexity measures
  - F.1.m Miscellaneous
- F.2 ANALYSIS OF ALGORITHMS AND PROBLEM COMPLEXITY (B.6, B.7, F.1.3)
  - F.2.0 General
  - F.2.1 Numerical Algorithms and Problems (G.1, G.4, I.1)
    - Computation of transforms (e.g., Fast Fourier transform)
    - Computations in finite fields
    - Computations on matrices
    - Computations on polynomials
    - Number-theoretic computations (e.g., factoring, primality testing)
  - F.2.2 Nonnumerical Algorithms and Problems (E.2, E.3, E.4, E.5, G.2, H.2, H.3)
    - Complexity of proof procedures
    - Computations on discrete structures
    - Geometrical problems and computations
    - Pattern matching
    - Routing and layout
    - Sequencing and scheduling
    - Sorting and searching
  - F.2.3 Tradeoffs among Complexity Measures (F.1.3)
  - F.2.m Miscellaneous
- F.3 LOGICS AND MEANINGS OF PROGRAMS
  - F.3.0 General
  - F.3.1 Specifying and Verifying and Reasoning about Programs (D.2.1, D.2.4, D.3.1, E.1)
    - Assertions
    - Invariants
    - Logics of programs
    - Mechanical verification
    - Pre- and post-conditions
    - Specification techniques
  - F.3.2 Semantics of Programming Languages (D.3.1)
    - Algebraic approaches to semantics
    - Denotational semantics
    - Operational semantics
  - F.3.3 Studies of Program Constructs (D.3.2, D.3.3)
    - Control primitives
    - Functional constructs
    - Program and recursion schemes
    - Type structure
  - F.3.m Miscellaneous
- F.4 MATHEMATICAL LOGIC AND FORMAL LANGUAGES
  - F.4.0 General
  - F.4.1 Mathematical Logic (F.1.1, I.2.2, I.2.3)
    - Computability theory
    - Computational logic
    - Lambda calculus and related systems
    - Logic programming
    - Mechanical theorem proving
    - Model theory
    - Proof theory
    - Recursive function theory
  - F.4.2 Grammars and Other Rewriting Systems (D.3.1)
    - Decision problems
    - Grammar types (e.g., context-free, context-sensitive)
    - Parallel rewriting systems (e.g., development systems, L-systems)
    - Parsing
    - Thue systems
  - F.4.3 Formal Languages (D.3.1)
    - Algebraic language theory
    - Classes defined by grammars or automata (e.g., context-free languages, regular sets, recursive sets)
    - Classes defined by resource-bounded automata
    - Decision problems
    - Operations on languages
  - F.4.m Miscellaneous
- F.m MISCELLANEOUS
G. Mathematics of Computing
- G.0 GENERAL
- G.1 NUMERICAL ANALYSIS
  - G.1.0 General
    - Computer arithmetic
    - Condition (and ill-condition)
    - Error analysis
    - Numerical algorithms
    - Parallel algorithms
    - Stability (and instability)
  - G.1.1 Interpolation
    - Difference formulas
    - Extrapolation
    - Interpolation formulas
    - Smoothing
    - Spline and piecewise polynomial interpolation
  - G.1.2 Approximation
    - Chebyshev approximation and theory
    - Elementary function approximation
    - Least squares approximation
    - Linear approximation
    - Minimax approximation and algorithms
    - Nonlinear approximation
    - Rational approximation
    - Spline and piecewise polynomial approximation
  - G.1.3 Numerical Linear Algebra
    - Conditioning
    - Determinants
    - Eigenvalues
    - Error analysis
    - Linear systems (direct and iterative methods)
    - Matrix inversion
    - Pseudoinverses
    - Sparse and very large systems
  - G.1.4 Quadrature and Numerical Differentiation
    - Adaptive quadrature
    - Equal interval integration
    - Error analysis
    - Finite difference methods
    - Gaussian quadrature
    - Iterative methods
    - Multiple quadrature
  - G.1.5 Roots of Nonlinear Equations
    - Convergence
    - Error analysis
    - Iterative methods
    - Polynomials, methods for
    - Systems of equations
  - G.1.6 Optimization
    - Constrained optimization
    - Gradient methods
    - Integer programming
    - Least squares methods
    - Linear programming
    - Nonlinear programming
  - G.1.7 Ordinary Differential Equations
    - Boundary value problems
    - Convergence and stability
    - Error analysis
    - Initial value problems
    - Multistep methods
    - Single step methods
    - Stiff equations
  - G.1.8 Partial Differential Equations
    - Difference methods
    - Elliptic equations
    - Finite element methods
    - Hyperbolic equations
    - Method of lines
    - Parabolic equations
  - G.1.9 Integral Equations
    - Fredholm equations
    - Integro-differential equations
    - Volterra equations
  - G.1.m Miscellaneous
- G.2 DISCRETE MATHEMATICS
  - G.2.0 General
  - G.2.1 Combinatorics (F.2.2)
    - Combinatorial algorithms
    - Counting problems
    - Generating functions
    - Permutations and combinations
    - Recurrences and difference equations
  - G.2.2 Graph Theory (F.2.2)
    - Graph algorithms
    - Network problems
    - Path and circuit problems
    - Trees
  - G.2.m Miscellaneous
- G.3 PROBABILITY AND STATISTICS
  - Probabilistic algorithms (including Monte Carlo)
  - Random number generation
  - Statistical computing
  - Statistical software
- G.4 MATHEMATICAL SOFTWARE
  - Algorithm analysis
  - Certification and testing
  - Efficiency
  - Portability
  - Reliability and robustness
  - Verification
- G.m MISCELLANEOUS
  - Queueing theory
H. Information Systems
- H.0 GENERAL
- H.1 MODELS AND PRINCIPLES
  - H.1.0 General
  - H.1.1 Systems and Information Theory (E.4)
    - General systems theory
    - Information theory
    - Value of information
  - H.1.2 User/Machine Systems
    - Human factors
    - Human information processing
  - H.1.m Miscellaneous
- H.2 DATABASE MANAGEMENT (E.5)
  - H.2.0 General
    - Security, integrity, and protection
  - H.2.1 Logical Design
    - Data models
    - Normal forms
    - Schema and subschema
  - H.2.2 Physical Design
    - Access methods
    - Deadlock avoidance
    - Recovery and restart
  - H.2.3 Languages (D.3.2)
    - Data description languages (DDL)
    - Data manipulation languages (DML)
    - Query languages
    - Report writers
  - H.2.4 Systems
    - Concurrency
    - Distributed systems
    - Query processing
    - Transaction processing
  - H.2.5 Heterogeneous Databases
    - Data translation
    - Program translation
  - H.2.6 Database Machines
  - H.2.7 Database Administration
    - Data dictionary/directory
    - Logging and recovery
  - H.2.8 Database Applications
  - H.2.m Miscellaneous
- H.3 INFORMATION STORAGE AND RETRIEVAL
  - H.3.0 General
  - H.3.1 Content Analysis and Indexing
    - Abstracting methods
    - Dictionaries
    - Indexing methods
    - Linguistic processing
    - Thesauruses
  - H.3.2 Information Storage
    - File organization
    - Record classification
  - H.3.3 Information Search and Retrieval
    - Clustering
    - Query formulation
    - Retrieval models
    - Search process
    - Selection process
  - H.3.4 Systems and Software
    - Current awareness systems (selective dissemination of information--SDI)
    - Information networks
    - Question-answering (fact retrieval) systems
  - H.3.5 Online Information Services
    - Data bank sharing
  - H.3.6 Library Automation
    - Large text archives
  - H.3.m Miscellaneous
- H.4 INFORMATION SYSTEMS APPLICATIONS
  - H.4.0 General
  - H.4.1 Office Automation (I.7)
    - Equipment
    - Spreadsheets
    - Time management (e.g., calendars, schedules)
    - Word processing
  - H.4.2 Types of Systems
    - Decision support (e.g., MIS)
    - Logistics
  - H.4.3 Communications Applications
    - Bulletin boards
    - Computer conferencing and teleconferencing
    - Electronic mail
    - Videotex
  - H.4.m Miscellaneous
- H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
  - H.5.0 General
  - H.5.1 Multimedia Information Systems
    - Animations
    - Artificial realities
    - Audio input/output
    - Evaluation/methodology
    - Hypertext navigation and maps
    - Video (e.g., tape, disk, DVI)
  - H.5.2 User Interfaces (D.2.2, H.1.2, I.3.6)
    - Ergonomics
    - Evaluation/methodology
    - Input devices and strategies (e.g., mouse, touchscreen)
    - Interaction styles (e.g., commands, menus, forms, direct manipulation)
    - Screen design (e.g., text, graphics, color)
    - Theory and methods
    - Training, help, and documentation
    - User interface management systems (UIMS)
    - Windowing systems
  - H.5.3 Group and Organization Interfaces
    - Asynchronous interaction
    - Evaluation/methodology
    - Organizational design
    - Synchronous interaction
    - Theory and models
- H.m MISCELLANEOUS
I. Computing Methodologies
- I.0 GENERAL
- I.1 ALGEBRAIC MANIPULATION
  - I.1.0 General
  - I.1.1 Expressions and Their Representation (E.1, E.2)
    - Representations (general and polynomial)
    - Simplification of expressions
  - I.1.2 Algorithms (F.2.1, F.2.2)
    - Algebraic algorithms
    - Analysis of algorithms
    - Nonalgebraic algorithms
  - I.1.3 Languages and Systems (D.3.2, D.3.3, F.2.2)
    - Evaluation strategies
    - Nonprocedural languages
    - Special-purpose algebraic systems
    - Special-purpose hardware
    - Substitution mechanisms
  - I.1.4 Applications
  - I.1.m Miscellaneous
- I.2 ARTIFICIAL INTELLIGENCE
  - I.2.0 General
    - Cognitive simulation
    - Philosophical foundations
  - I.2.1 Applications and Expert Systems (H.4, J)
    - Cartography
    - Games
    - Industrial automation
    - Law
    - Medicine and science
    - Natural language interfaces
    - Office automation
  - I.2.2 Automatic Programming (D.1.2, F.3.1)
    - Automatic analysis of algorithms
    - Program modification
    - Program synthesis
    - Program transformation
    - Program verification
  - I.2.3 Deduction and Theorem Proving
    - Answer/reason extraction
    - Deduction (e.g., natural, rule-based)
    - Logic programming
    - Mathematical induction
    - Metatheory
    - Nonmonotonic reasoning and belief revision
    - Resolution
    - Uncertainty, "fuzzy," and probabilistic reasoning
  - I.2.4 Knowledge Representation Formalisms and Methods
    - Frames and scripts
    - Predicate logic
    - Relation systems
    - Representation languages
    - Representations (procedural and rule-based)
    - Semantic networks
  - I.2.5 Programming Languages and Software (D.3.2)
    - Expert system tools and techniques
  - I.2.6 Learning (K.3.2)
    - Analogies
    - Concept learning
    - Connectionism and neural nets
    - Induction
    - Knowledge acquisition
    - Language acquisition
    - Parameter learning
  - I.2.7 Natural Language Processing
    - Discourse
    - Language generation
    - Language models
    - Language parsing and understanding
    - Machine translation
    - Speech recognition and synthesis
    - Text analysis
  - I.2.8 Problem Solving, Control Methods, and Search (F.2.2)
    - Backtracking
    - Dynamic programming
    - Graph and tree search strategies
    - Heuristic methods
    - Plan execution, formation, generation
  - I.2.9 Robotics
    - Manipulators
    - Propelling mechanisms
    - Sensors
  - I.2.10 Vision and Scene Understanding (I.4.8, I.5)
    - Architecture and control structures
    - Intensity, color, photometry and thresholding
    - Modeling and recovery of physical attributes
    - Motion
    - Perceptual reasoning
    - Representations, data structures, and transforms
    - Shape
    - Texture
  - I.2.11 Distributed Artificial Intelligence
    - Coherence and coordination
    - Languages and structures
  - I.2.m Miscellaneous
- I.3 COMPUTER GRAPHICS
  - I.3.0 General
  - I.3.1 Hardware Architecture (B.4.2)
    - Graphics processors
    - Hardcopy devices
    - Input devices
    - Parallel processing
    - Raster display devices
    - Storage devices
    - Three-dimensional displays
    - Vector display devices
  - I.3.2 Graphics Systems (C.2.1, C.2.4, C.3)
    - Distributed/network graphics
    - Remote systems
    - Stand-alone systems
  - I.3.3 Picture/Image Generation
    - Antialiasing
    - Bitmap and framebuffer operations
    - Digitizing and scanning
    - Display algorithms
    - Line and curve generation
    - Viewing algorithms
  - I.3.4 Graphics Utilities
    - Application packages
    - Device drivers
    - Graphics editors
    - Graphics packages
    - Meta files
    - Paint systems
    - Picture description languages
    - Software support
    - Virtual device interfaces
  - I.3.5 Computational Geometry and Object Modeling
    - Boundary representations
    - Constructive solid geometry (CSG)
    - Curve, surface, solid, and object representations
    - Geometric algorithms, languages, and systems
    - Hierarchy and geometric transformations
    - Modeling packages
    - Object hierarchies
    - Physically based modeling
    - Splines
  - I.3.6 Methodology and Techniques
    - Device independence
    - Ergonomics
    - Graphics data structures and data types
    - Interaction techniques
    - Languages
    - Standards
  - I.3.7 Three-Dimensional Graphics and Realism
    - Animation
    - Color, shading, shadowing, and texture
    - Fractals
    - Hidden line/surface removal
    - Radiosity
    - Raytracing
    - Virtual reality
    - Visible line/surface algorithms
  - I.3.8 Applications
  - I.3.m Miscellaneous
- I.4 IMAGE PROCESSING
  - I.4.0 General
    - Image displays
    - Image processing software
  - I.4.1 Digitization
    - Quantization
    - Sampling
    - Scanning
  - I.4.2 Compression (Coding) (E.4)
    - Approximate methods
    - Exact coding
  - I.4.3 Enhancement
    - Filtering
    - Geometric correction
    - Grayscale manipulation
    - Registration
    - Sharpening and deblurring
    - Smoothing
  - I.4.4 Restoration
    - Inverse filtering
    - Kalman filtering
    - Pseudoinverse restoration
    - Wiener filtering
  - I.4.5 Reconstruction
    - Series expansion methods
    - Summation methods
    - Transform methods
  - I.4.6 Segmentation
    - Edge and feature detection
    - Pixel classification
    - Region growing, partitioning
  - I.4.7 Feature Measurement
    - Invariants
    - Moments
    - Projections
    - Size and shape
    - Texture
  - I.4.8 Scene Analysis
    - Depth cues
    - Photometry
    - Range data
    - Sensor fusion
    - Stereo
    - Time-varying imagery
  - I.4.9 Applications
  - I.4.10 Image Representation
    - Hierarchical
    - Morphological
    - Multidimensional
    - Statistical
    - Volumetric
  - I.4.m Miscellaneous
- I.5 PATTERN RECOGNITION
  - I.5.0 General
  - I.5.1 Models
    - Deterministic
    - Fuzzy set
    - Geometric
    - Neural nets
    - Statistical
    - Structural
  - I.5.2 Design Methodology
    - Classifier design and evaluation
    - Feature evaluation and selection
    - Pattern analysis
  - I.5.3 Clustering
    - Algorithms
    - Similarity measures
  - I.5.4 Applications
    - Computer vision
    - Signal processing
    - Text processing
    - Waveform analysis
  - I.5.5 Implementation (C.3)
    - Interactive systems
    - Special architectures
  - I.5.m Miscellaneous
- I.6 SIMULATION AND MODELING (G.3)
  - I.6.0 General
  - I.6.1 Simulation Theory
    - Model classification
    - Systems theory
    - Types of simulation (continuous and discrete)*
  - I.6.2 Simulation Languages
  - I.6.3 Applications
  - I.6.4 Model Validation and Analysis
  - I.6.5 Model Development
    - Modeling methodologies
  - I.6.6 Simulation Output Analysis
  - I.6.7 Simulation Support Systems
    - Environments
  - I.6.8 Types of Simulation
    - Animation
    - Combined
    - Continuous
    - Discrete event
    - Distributed
    - Gaming
    - Monte Carlo
    - Parallel
    - Visual
  - I.6.m Miscellaneous
- I.7 TEXT PROCESSING (H.4, H.5)
  - I.7.0 General
  - I.7.1 Text Editing
    - Languages
    - Spelling
  - I.7.2 Document Preparation
    - Desktop publishing
    - Format and notation
    - Hypertext/hypermedia
    - Languages and systems
    - Multi/mixed media
    - Photocomposition/typesetting
    - Standards
  - I.7.3 Index Generation
  - I.7.m Miscellaneous
- I.m MISCELLANEOUS
J. Computer Applications
- J.0 General
- J.1 ADMINISTRATIVE DATA PROCESSING
  - Business
  - Education
  - Financial (e.g., EFTS)
  - Government
  - Law
  - Manufacturing
  - Marketing
  - Military
- J.2 PHYSICAL SCIENCES AND ENGINEERING
  - Aerospace
  - Astronomy
  - Chemistry
  - Earth and atmospheric sciences
  - Electronics
  - Engineering
  - Mathematics and statistics
  - Physics
- J.3 LIFE AND MEDICAL SCIENCES
  - Biology
  - Health
  - Medical information systems
- J.4 SOCIAL AND BEHAVIORAL SCIENCES
  - Economics
  - Psychology
  - Sociology
- J.5 ARTS AND HUMANITIES
  - Arts, fine and performing
  - Language translation
  - Linguistics
  - Literature
  - Music
- J.6 COMPUTER-AIDED ENGINEERING
  - Computer-aided design (CAD)
  - Computer-aided manufacturing (CAM)
- J.7 COMPUTERS IN OTHER SYSTEMS (C.3)
  - Command and control
  - Consumer products
  - Industrial control
  - Military
  - Process control
  - Publishing
  - Real time
- J.m MISCELLANEOUS
K. Computing Milieux
- K.0 GENERAL
- K.1 THE COMPUTER INDUSTRY
  - Markets
  - Standards
  - Statistics
  - Suppliers
- K.2 HISTORY OF COMPUTING
  - Hardware
  - People
  - Software
  - Systems
  - Theory
- K.3 COMPUTERS AND EDUCATION
  - K.3.0 General
  - K.3.1 Computer Uses in Education
    - Computer-assisted instruction (CAI)
    - Computer-managed instruction (CMI)
  - K.3.2 Computer and Information Science Education
    - Computer science education
    - Curriculum
    - Information systems education
    - Self-assessment
  - K.3.m Miscellaneous
    - Accreditation
    - Computer literacy
- K.4 COMPUTERS AND SOCIETY
  - K.4.0 General
  - K.4.1 Public Policy Issues
    - Human safety
    - Privacy
    - Regulation
    - Transborder data flow
  - K.4.2 Social Issues
    - Abuse and crime involving computers
    - Employment
    - Handicapped persons/special needs
  - K.4.3 Organizational Impacts
  - K.4.m Miscellaneous
- K.5 LEGAL ASPECTS OF COMPUTING
  - K.5.0 General
  - K.5.1 Software Protection
    - Copyrights
    - Patents
    - Proprietary rights
    - Trade secrets
  - K.5.2 Governmental Issues
    - Regulation
    - Taxation
  - K.5.m Miscellaneous
    - Contracts
    - Hardware patents
- K.6 MANAGEMENT OF COMPUTING AND INFORMATION SYSTEMS
  - K.6.0 General
    - Economics
  - K.6.1 Project and People Management
    - Life cycle
    - Management techniques (e.g., PERT/CPM)
    - Staffing
    - Systems analysis and design
    - Systems development
    - Training
  - K.6.2 Installation Management
    - Benchmarks
    - Computer selection
    - Computing equipment management
    - Performance and usage measurement
    - Pricing and resource allocation
  - K.6.3 Software Management
    - Software development
    - Software maintenance
    - Software selection
  - K.6.4 System Management
    - Centralization/decentralization
    - Management audit
    - Quality assurance
  - K.6.5 Security and Protection (D.4.6, K.4.2)
    - Authentication
    - Insurance
    - Invasive software (e.g., viruses, worms, Trojan horses)
    - Physical security
  - K.6.m Miscellaneous
    - Insurance*
    - Security*
- K.7 THE COMPUTING PROFESSION
  - K.7.0 General
  - K.7.1 Occupations
  - K.7.2 Organizations
  - K.7.3 Testing, Certification, and Licensing
  - K.7.m Miscellaneous
    - Codes of good practice
    - Ethics
- K.8 PERSONAL COMPUTING
  - Games*
  - K.8.0 General
    - Games
  - K.8.1 Application Packages
    - Data communications
    - Database processing
    - Graphics
    - Spreadsheets
    - Word processing
  - K.8.2 Hardware
  - K.8.3 Management/Maintenance
- K.m MISCELLANEOUS

*Indicates that the classification is no longer be used as of January 1991, but that the item is still searchable for previously classified documents.