# The 1991 ACM Computing Classification System

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## The ACM Computing Classification System (1991)

- A. General Literature
- 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.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.2.0 General
- 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.m MISCELLANEOUS

- C.0 GENERAL
- D. Software
- D.0 GENERAL
- D.1 PROGRAMMING TECHNIQUES (E)
- 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.2.0 General (K.5.1)
- 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.3.0 General
- 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.1.0 General
- G.2 DISCRETE MATHEMATICS
- 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.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.2.0 General
- 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.2.0 General
- 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.4.0 General
- 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.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.5 LEGAL ASPECTS OF COMPUTING
- 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

- K.6.0 General
- K.7 THE COMPUTING PROFESSION
- K.8 PERSONAL COMPUTING
- 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.