NDFA Designing where every string starts and ends with same

Duration: 6 min

This video lesson is available to enrolled students.

Return to /learn/MPPSC-ASSISTANT-PROFESSOR-COMPUTER-SCIENCE-PAPER-2/theory-of-computation/non-deterministic-fa/nfa-basics-design/asset-ndfa-designing-where-every-string-starts-and-ends-with-same after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. Paper 1 | General Studies: State Wise GK
  3. Paper 1 | Information and Communication Technology: Role of Internet and Web Services, Security in Mobile and Wireless Computing
  4. Paper 1 | Current Affairs: GK- Current Affairs
  5. Paper 2 | Discrete Mathematical Structure: प्रतिशतता / Percentage, अनुपात, समानुपात, साझेदारी एवं मिश्रण / Ratio, Proportion, Partnership and Mixtures, औसत / Averages, आँकड़ा विश्लेषण एवं शोध सांख्यिकी / Data Analysis and Statistics in Research, क्रमचय, संचय एवं प्रायिकता / Permutation, Combination and Probability, श्रेणी / Series, आँकड़े एवं आलेखीय निरूपण / Data and Graphical Representation, आँकड़ा निर्वचन: तालिका / Data Interpretation: Tables, Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic, Descriptive statistics, exploratory data analysis, Standard discrete and continuous univariate distributions, Univariate and Joint Distributions, Markov Chains
  6. Paper 2 | Digital Computer Organization And Architecture: Number System, Number Representation, Sequential Circuits, Combinational Circuit, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. Paper 2 | C Programming: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling
  8. Paper 2 | Programming Languages & Object-Oriented Programming Concepts: Java, OOPS with C++, Java Fundamentals, Array, String, IO & References
  9. Paper 2 | Python: Introduction to Python, Tokens, Variables, Data Types, I/O, Operators & Expressions, Control Flow & Looping, Collections & Strings, Functions & Modules, File Handling & Data Analysis
  10. Paper 2 | Data Structure And Algorithms: Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Minimum Spanning Trees, Advanced Algorithms
  11. Paper 2 | Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Deadlock, Threads & Process Creation, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS
  12. Paper 2 | Theory Of Computation: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory
  13. Paper 2 | Compiler Design: Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  14. Paper 2 | Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, Relational Algebra, SQL, Transaction Management, Concurrency Control, Database Recovery, Database Security & Authorization, Enhanced Data Models
  15. Paper 2 | Computer Network And Information Security: Introduction to CN, Data Communication, Application Layer, Hardware basics, Cyber Threats and Malware Attacks, Network Security, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP
  16. Paper 2 | Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management
  17. Paper 2 | Current Trends & Technologies: कंप्यूटर की मूल बातें और हार्डवेयर / Computer Fundamentals and Hardware, पारितंत्र और जैव विविधता / Ecosystems and Biodiversity, मेमोरी, भंडारण और डेटा निरूपण / Memory, Storage and Data Representation, कंप्यूटर सॉफ्टवेयर / Computer Software, निरुपाधिक प्रतिज्ञप्तियाँ / Categorical Propositions, ऑफिस अनुप्रयोग / Office Applications, संकेत विज्ञान एवं अर्थ / Semiotics and Meaning, मल्टीमीडिया और फ़ाइल प्रारूप / Multimedia and File Formats, कंप्यूटर नेटवर्क / Computer Networks, संचार की बाधाएँ / Barriers to Communication, उच्च शिक्षा संस्थानों के प्रकार / Types of Higher Education Institutions, इंटरनेट और वर्ल्ड वाइड वेब / Internet and World Wide Web, ई-मेल और ऑनलाइन संचार / Email and Online Communication, शिक्षण विधियाँ / Methods of Teaching, साइबर सुरक्षा / Cyber Security, डिजिटल नैतिकता, बौद्धिक संपदा और समाज / Digital Ethics, IPR and Society, शोध-प्रबंध एवं लेख लेखन / Thesis and Article Writing, डिजिटल एवं नव माध्यम / Digital and New Media, उभरती प्रौद्योगिकियाँ / Emerging Technologies, प्राकृतिक प्रकोप और आपदा प्रबंधन / Natural Hazards and Disaster Management, शिक्षा और शासन में ICT / ICT in Education and Governance, क्लाउड और वितरित कंप्यूटिंग / Cloud and Distributed Computing, Approaches to AI, Search Algorithms, Game Playing, Knowledge Representation, Planning, Multi Agent Systems, Fuzzy Sets, Natural Language Processing, Artificial Neural Networks, Genetic Algorithms, Data Warehousing & Mining, Electronic Data Interchange and E-Commerce
  18. Paper 2 | Full Length Mock Tests:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

The video lecture addresses a problem in formal language theory: designing a Non-deterministic Finite Automaton (NFA) that accepts all strings over the alphabet $\Sigma = \{a, b\}$ where every accepted string starts and ends with the same symbol. The instructor begins by clarifying that NDFA is synonymous with NFA. He then proceeds to construct the automaton step-by-step on a digital whiteboard. He starts by defining the start state $q_0$ and considers the implications of the string starting with 'a' or 'b'. He draws initial transitions and states, realizing the need to track the starting symbol to ensure the ending symbol matches. He introduces intermediate states to handle the "middle" part of the string, allowing for any sequence of characters. The final design involves branching paths that converge at an accepting state only if the start and end symbols are identical.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The instructor introduces the problem statement written on the screen: "Design a NFA that accepts all strings over the alphabet $\Sigma = \{a, b\}$ such that every accepted string start and end with same symbol." He writes "NDFA = NFA" to clarify terminology. He begins drawing the NFA, starting with a state $q_0$. He draws a transition on 'a' to a state $q_1$ and another to $q_2$. He adds a self-loop on $q_2$ labeled 'a, b'. He writes "a x a" and "b x b" to indicate the requirement for matching start and end symbols. He draws a triangle structure connecting $q_0, q_1, q_2$ to visualize the flow.

  2. 2:00 – 5:00 02:00-05:00

    The instructor refines the NFA design by drawing a new, more structured diagram on the right side. He creates a start state $q_0$ with a transition on 'a' leading to state $q_2$ and a transition on 'b' leading to state $q_3$. He adds self-loops on both $q_2$ and $q_3$ labeled 'a, b' to represent the arbitrary middle section of the string. He then draws transitions from $q_2$ to an accepting state $q_1$ on input 'a' and from $q_3$ to $q_1$ on input 'b'. He also adds a direct transition from $q_0$ to $q_1$ labeled 'a, b' to handle strings of length one.

  3. 5:00 – 5:53 05:00-05:53

    The instructor finalizes the diagram and explains the logic behind the transitions. He points to the self-loops on $q_2$ and $q_3$, explaining that they allow for any number of 'a's and 'b's in the middle of the string. He emphasizes that the path taken depends on the first symbol read. If the string starts with 'a', the machine goes to $q_2$ and must end with 'a' to reach $q_1$. Similarly for 'b'. He concludes by confirming that this NFA correctly accepts the language defined in the problem.

The lecture provides a clear example of NFA construction for a language defined by start and end conditions. The core strategy involves using non-determinism to guess the starting symbol and then verifying it at the end. By creating separate paths for 'a' and 'b' starts, the NFA can handle the two cases independently. The self-loops on the intermediate states are crucial for accepting strings of any length greater than one. This approach highlights the power of non-determinism in simplifying automata design compared to deterministic approaches.

Loading lesson…