JHU Course Reviews
Johns Hopkins University
Code | Name | Overall | Easiness | Interest | Usefulness | Reviewssorted descending |
---|---|---|---|---|---|---|
EN601 280 | Full-Stack JavaScript | 5 | 4 | 5 | 5 | 1 |
EN601 426 | Principles of Programming Languages | 0 | 0 | 0 | 0 | 0 |
EN601 315 | Databases | 0 | 0 | 0 | 0 | 0 |
EN601 318 | Operating Systems | 0 | 0 | 0 | 0 | 0 |
EN601 329 | Functional Programming in Software Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 350 | Genomic Data Science | 0 | 0 | 0 | 0 | 0 |
EN601 382 | Deep Learning Lab | 0 | 0 | 0 | 0 | 0 |
EN601 411 | Computer Science Innovation & Entrepreneurship II | 0 | 0 | 0 | 0 | 0 |
EN601 415 | Databases | 0 | 0 | 0 | 0 | 0 |
EN601 418 | Operating Systems | 0 | 0 | 0 | 0 | 0 |
EN601 420 | Parallel Programming | 0 | 0 | 0 | 0 | 0 |
EN601 422 | Software Testing & Debugging | 0 | 0 | 0 | 0 | 0 |
EN601 295 | Developing Health IT Applications | 0 | 0 | 0 | 0 | 0 |
EN601 428 | Compilers & Interpreters | 0 | 0 | 0 | 0 | 0 |
EN601 430 | Combinatorics & Graph Theory in Computer Science | 0 | 0 | 0 | 0 | 0 |
EN601 434 | Randomized and Big Data Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 436 | Algorithmic Game Theory | 0 | 0 | 0 | 0 | 0 |
EN601 440 | Web Security | 0 | 0 | 0 | 0 | 0 |
EN601 442 | Modern Cryptography | 0 | 0 | 0 | 0 | 0 |
EN601 443 | Security & Privacy in Computing | 0 | 0 | 0 | 0 | 0 |
EN601 445 | Practical Cryptographic Systems | 0 | 0 | 0 | 0 | 0 |
EN601 447 | Computational Genomics: Sequences | 0 | 0 | 0 | 0 | 0 |
EN601 452 | Computational Biomedical Research | 0 | 0 | 0 | 0 | 0 |
EN601 819 | Selected Topics in Cloud Computing and Networked Systems | 0 | 0 | 0 | 0 | 0 |
EN601 691 | Human-Robot Interaction | 0 | 0 | 0 | 0 | 0 |
EN601 717 | Advanced Distributed Systems & Networks | 0 | 0 | 0 | 0 | 0 |
EN601 718 | Advanced Operating Systems | 0 | 0 | 0 | 0 | 0 |
EN601 740 | Language-based Security | 0 | 0 | 0 | 0 | 0 |
EN601 742 | Advanced Topics in Cryptography | 0 | 0 | 0 | 0 | 0 |
EN601 745 | Advanced Topics in Applied Cryptography | 0 | 0 | 0 | 0 | 0 |
EN601 760 | FFT in Graphics & Vision | 0 | 0 | 0 | 0 | 0 |
EN601 767 | Deep Learning for Automated Discourse | 0 | 0 | 0 | 0 | 0 |
EN601 778 | Advanced Topics in Causal Inference | 0 | 0 | 0 | 0 | 0 |
EN601 810 | Diversity and Inclusion in Computer Science and Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 455 | Computer Integrated Surgery I | 0 | 0 | 0 | 0 | 0 |
EN601 831 | CS Theory Seminar | 0 | 0 | 0 | 0 | 0 |
EN601 845 | Selected Topics in Applied Cryptography | 0 | 0 | 0 | 0 | 0 |
EN601 857 | Selected Topics in Computer Graphics | 0 | 0 | 0 | 0 | 0 |
EN601 868 | Selected Topics in Machine Translation | 0 | 0 | 0 | 0 | 0 |
EN601 105 | CS First-year Experience | 0 | 0 | 0 | 0 | 0 |
EN601 108 | Introduction to Programming Lab | 0 | 0 | 0 | 0 | 0 |
EN601 226 | Data Structures | 0 | 0 | 0 | 0 | 0 |
EN601 230 | Mathematical Foundations for Computer Science | 0 | 0 | 0 | 0 | 0 |
EN601 270 | Open Source Software Engineering (Semesters of Code I) | 0 | 0 | 0 | 0 | 0 |
EN601 807 | Teaching Practicum | 0 | 0 | 0 | 0 | 0 |
EN601 749 | Computational Genomics: Applied Comparative Genomics | 0 | 0 | 0 | 0 | 0 |
EN601 765 | Machine Learning: Linguistic & Sequence Modeling | 0 | 0 | 0 | 0 | 0 |
EN601 769 | Events Semantics in Theory and Practice | 0 | 0 | 0 | 0 | 0 |
EN601 779 | Machine Learning: Advanced Topics | 0 | 0 | 0 | 0 | 0 |
EN601 780 | Unsupervised Learning: From Big Data to Low-Dimensional Repr... | 0 | 0 | 0 | 0 | 0 |
EN601 783 | Vision as Bayesian Inference | 0 | 0 | 0 | 0 | 0 |
EN601 787 | Advanced Machine Learning: Machine Learning for Trustworthy... | 0 | 0 | 0 | 0 | 0 |
EN601 801 | Computer Science Seminar | 0 | 0 | 0 | 0 | 0 |
EN601 803 | Masters Research | 0 | 0 | 0 | 0 | 0 |
EN601 805 | Graduate Independent Study | 0 | 0 | 0 | 0 | 0 |
EN601 743 | Advanced Topics in Computer Security | 0 | 0 | 0 | 0 | 0 |
EN601 808 | Selected Topics in CS Education | 0 | 0 | 0 | 0 | 0 |
EN601 809 | PhD Research | 0 | 0 | 0 | 0 | 0 |
EN601 814 | Selected Topics in Computer Networks | 0 | 0 | 0 | 0 | 0 |
EN601 817 | Selected Topics in Systems Research | 0 | 0 | 0 | 0 | 0 |
EN601 826 | Selected Topics in Programming Languages | 0 | 0 | 0 | 0 | 0 |
EN601 833 | Seminar in Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 856 | Seminar: Medical Image Analysis | 0 | 0 | 0 | 0 | 0 |
EN601 865 | Selected Topics in Natural Language Processing | 0 | 0 | 0 | 0 | 0 |
EN601 866 | Selected Topics in Computational Semantics | 0 | 0 | 0 | 0 | 0 |
EN601 875 | Selected Topics in Machine Learning | 0 | 0 | 0 | 0 | 0 |
EN601 503 | Independent Study | 0 | 0 | 0 | 0 | 0 |
EN601 457 | Computer Graphics | 0 | 0 | 0 | 0 | 0 |
EN601 461 | Computer Vision | 0 | 0 | 0 | 0 | 0 |
EN601 464 | Artificial Intelligence | 0 | 0 | 0 | 0 | 0 |
EN601 466 | Information Retrieval and Web Agents | 0 | 0 | 0 | 0 | 0 |
EN601 468 | Machine Translation | 0 | 0 | 0 | 0 | 0 |
EN601 475 | Machine Learning | 0 | 0 | 0 | 0 | 0 |
EN601 477 | Causal Inference | 0 | 0 | 0 | 0 | 0 |
EN601 482 | Machine Learning: Deep Learning | 0 | 0 | 0 | 0 | 0 |
EN601 490 | Introduction to Human-Computer Interaction | 0 | 0 | 0 | 0 | 0 |
EN601 496 | Computer Integrated Surgery II - Teams | 0 | 0 | 0 | 0 | 0 |
EN601 690 | Introduction to Human-Computer Interaction | 0 | 0 | 0 | 0 | 0 |
EN601 509 | Computer Science Internship | 0 | 0 | 0 | 0 | 0 |
EN601 519 | Senior Honors Thesis | 0 | 0 | 0 | 0 | 0 |
EN601 556 | Senior Thesis in CIS | 0 | 0 | 0 | 0 | 0 |
EN601 614 | Computer Networks | 0 | 0 | 0 | 0 | 0 |
EN601 617 | Distributed Systems | 0 | 0 | 0 | 0 | 0 |
EN601 618 | Operating Systems | 0 | 0 | 0 | 0 | 0 |
EN601 685 | Probabilistic Models in the Visual Cortex | 0 | 0 | 0 | 0 | 0 |
EN601 714 | Advanced Computer Networks | 0 | 0 | 0 | 0 | 0 |
EN601 723 | Advanced Topics in Data-Intensive Computing | 0 | 0 | 0 | 0 | 0 |
EN601 741 | Advanced Topics in Secure and Censorship-Resistant Communica... | 0 | 0 | 0 | 0 | 0 |
EN601 476 | Machine Learning: Data to Models | 0 | 0 | 0 | 0 | 0 |
EN601 444 | Network Security | 0 | 0 | 0 | 0 | 0 |
EN601 446 | Sketching and Indexing for Sequences | 0 | 0 | 0 | 0 | 0 |
EN601 448 | Computational Genomics: Data Analysis | 0 | 0 | 0 | 0 | 0 |
EN601 454 | Augmented Reality | 0 | 0 | 0 | 0 | 0 |
EN601 456 | Computer Integrated Surgery II | 0 | 0 | 0 | 0 | 0 |
EN601 459 | Computational Geometry | 0 | 0 | 0 | 0 | 0 |
EN601 463 | Algorithms for Sensor-Based Robotics | 0 | 0 | 0 | 0 | 0 |
EN601 465 | Natural Language Processing | 0 | 0 | 0 | 0 | 0 |
EN601 467 | Introduction to Human Language Technology | 0 | 0 | 0 | 0 | 0 |
EN601 474 | ML: Learning Theory | 0 | 0 | 0 | 0 | 0 |
EN601 441 | Blockchains and Cryptocurrencies | 0 | 0 | 0 | 0 | 0 |
EN601 481 | Machine Learning: Optimization | 0 | 0 | 0 | 0 | 0 |
EN601 486 | Machine Learning: Artificial Intelligence System Design & De... | 0 | 0 | 0 | 0 | 0 |
EN601 491 | Human-Robot Interaction | 0 | 0 | 0 | 0 | 0 |
EN601 501 | Computer Science Workshop | 0 | 0 | 0 | 0 | 0 |
EN601 507 | Undergraduate Research | 0 | 0 | 0 | 0 | 0 |
EN601 517 | Group Undergraduate Research | 0 | 0 | 0 | 0 | 0 |
EN601 520 | Senior Honors Thesis | 0 | 0 | 0 | 0 | 0 |
EN601 611 | Computer Science Innovation & Entrepreneurship II | 0 | 0 | 0 | 0 | 0 |
EN601 615 | Databases | 0 | 0 | 0 | 0 | 0 |
EN601 619 | Cloud Computing | 0 | 0 | 0 | 0 | 0 |
EN601 402 | Digital Health and Biomedical Informatics | 0 | 0 | 0 | 0 | 0 |
EN601 107 | Introductory Programming in Java | 0 | 0 | 0 | 0 | 0 |
EN601 220 | Intermediate Programming | 0 | 0 | 0 | 0 | 0 |
EN601 229 | Computer System Fundamentals | 0 | 0 | 0 | 0 | 0 |
EN601 231 | Automata & Computation Theory | 0 | 0 | 0 | 0 | 0 |
EN601 277 | Disinformation Self-Defense | 0 | 0 | 0 | 0 | 0 |
EN601 290 | User Interfaces and Mobile Applications | 0 | 0 | 0 | 0 | 0 |
EN601 310 | Software for Resilient Communities | 0 | 0 | 0 | 0 | 0 |
EN601 320 | Parallel Programming | 0 | 0 | 0 | 0 | 0 |
EN601 340 | Web Security | 0 | 0 | 0 | 0 | 0 |
EN601 356 | Seminar: Computer Integrated Surgery II | 0 | 0 | 0 | 0 | 0 |
EN601 620 | Parallel Programming | 0 | 0 | 0 | 0 | 0 |
EN601 414 | Computer Networks | 0 | 0 | 0 | 0 | 0 |
EN601 417 | Distributed Systems | 0 | 0 | 0 | 0 | 0 |
EN601 419 | Cloud Computing | 0 | 0 | 0 | 0 | 0 |
EN601 421 | Object Oriented Software Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 424 | Reliable Software Systems | 0 | 0 | 0 | 0 | 0 |
EN601 427 | Principles of Programming Languages II | 0 | 0 | 0 | 0 | 0 |
EN601 429 | Functional Programming in Software Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 433 | Intro Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 435 | Approximation Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 437 | Federated Learning and Analytics | 0 | 0 | 0 | 0 | 0 |
EN601 665 | Natural Language Processing | 0 | 0 | 0 | 0 | 0 |
EN601 647 | Computational Genomics: Sequences | 0 | 0 | 0 | 0 | 0 |
EN601 648 | Computational Genomics: Data Analysis | 0 | 0 | 0 | 0 | 0 |
EN601 654 | Augmented Reality | 0 | 0 | 0 | 0 | 0 |
EN601 655 | Computer Integrated Surgery I | 0 | 0 | 0 | 0 | 0 |
EN601 656 | Computer Integrated Surgery II | 0 | 0 | 0 | 0 | 0 |
EN601 657 | Computer Graphics | 0 | 0 | 0 | 0 | 0 |
EN601 659 | Computational Geometry | 0 | 0 | 0 | 0 | 0 |
EN601 661 | Computer Vision | 0 | 0 | 0 | 0 | 0 |
EN601 663 | Algorithms for Sensor-Based Robotics | 0 | 0 | 0 | 0 | 0 |
EN601 664 | Artificial Intelligence | 0 | 0 | 0 | 0 | 0 |
EN601 646 | Sketching and Indexing for Sequences | 0 | 0 | 0 | 0 | 0 |
EN601 666 | Information Retrieval and Web Agents | 0 | 0 | 0 | 0 | 0 |
EN601 667 | Introduction to Human Language Technology | 0 | 0 | 0 | 0 | 0 |
EN601 668 | Machine Translation | 0 | 0 | 0 | 0 | 0 |
EN601 674 | ML: Learning Theory | 0 | 0 | 0 | 0 | 0 |
EN601 675 | Machine Learning | 0 | 0 | 0 | 0 | 0 |
EN601 676 | Machine Learning: Data to Models | 0 | 0 | 0 | 0 | 0 |
EN601 677 | Causal Inference | 0 | 0 | 0 | 0 | 0 |
EN601 681 | Machine Learning: Optimization | 0 | 0 | 0 | 0 | 0 |
EN601 682 | Machine Learning: Deep Learning | 0 | 0 | 0 | 0 | 0 |
EN601 686 | Machine Learning: Artificial Intelligence System Design & De... | 0 | 0 | 0 | 0 | 0 |
EN601 634 | Randomized and Big Data Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 621 | Object Oriented Software Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 622 | Software Testing & Debugging | 0 | 0 | 0 | 0 | 0 |
EN601 624 | Reliable Software Systems | 0 | 0 | 0 | 0 | 0 |
EN601 626 | Principles of Programming Languages | 0 | 0 | 0 | 0 | 0 |
EN601 627 | Principles of Programming Languages II | 0 | 0 | 0 | 0 | 0 |
EN601 628 | Compilers & Interpreters | 0 | 0 | 0 | 0 | 0 |
EN601 629 | Functional Programming in Software Engineering | 0 | 0 | 0 | 0 | 0 |
EN601 630 | Combinatorics & Graph Theory in Computer Science | 0 | 0 | 0 | 0 | 0 |
EN601 631 | Theory of Computation | 0 | 0 | 0 | 0 | 0 |
EN601 633 | Intro Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 104 | Computer Ethics | 0 | 0 | 0 | 0 | 0 |
EN601 635 | Approximation Algorithms | 0 | 0 | 0 | 0 | 0 |
EN601 636 | Algorithmic Game Theory | 0 | 0 | 0 | 0 | 0 |
EN601 637 | Federated Learning and Analytics | 0 | 0 | 0 | 0 | 0 |
EN601 640 | Web Security | 0 | 0 | 0 | 0 | 0 |
EN601 641 | Blockchains and Cryptocurrencies | 0 | 0 | 0 | 0 | 0 |
EN601 642 | Modern Cryptography | 0 | 0 | 0 | 0 | 0 |
EN601 643 | Security & Privacy in Computing | 0 | 0 | 0 | 0 | 0 |
EN601 644 | Network Security | 0 | 0 | 0 | 0 | 0 |
EN601 645 | Practical Cryptographic Systems | 0 | 0 | 0 | 0 | 0 |
EN601 280
Full-Stack JavaScript
EN601 426
Principles of Programming Languages
EN601 315
Databases
EN601 318
Operating Systems
EN601 329
Functional Programming in Software Engineering
EN601 350
Genomic Data Science
EN601 382
Deep Learning Lab
EN601 411
Computer Science Innovation & Entrepreneurship II
EN601 415
Databases
EN601 418
Operating Systems
EN601 420
Parallel Programming
EN601 422
Software Testing & Debugging
EN601 295
Developing Health IT Applications
EN601 428
Compilers & Interpreters
EN601 430
Combinatorics & Graph Theory in Computer Science
EN601 434
Randomized and Big Data Algorithms
EN601 436
Algorithmic Game Theory
EN601 440
Web Security
EN601 442
Modern Cryptography
EN601 443
Security & Privacy in Computing
EN601 445
Practical Cryptographic Systems
EN601 447
Computational Genomics: Sequences
EN601 452
Computational Biomedical Research
EN601 819
Selected Topics in Cloud Computing and Networked Systems
EN601 691
Human-Robot Interaction
EN601 717
Advanced Distributed Systems & Networks
EN601 718
Advanced Operating Systems
EN601 740
Language-based Security
EN601 742
Advanced Topics in Cryptography
EN601 745
Advanced Topics in Applied Cryptography
EN601 760
FFT in Graphics & Vision
EN601 767
Deep Learning for Automated Discourse
EN601 778
Advanced Topics in Causal Inference
EN601 810
Diversity and Inclusion in Computer Science and Engineering
EN601 455
Computer Integrated Surgery I
EN601 831
CS Theory Seminar
EN601 845
Selected Topics in Applied Cryptography
EN601 857
Selected Topics in Computer Graphics
EN601 868
Selected Topics in Machine Translation
EN601 105
CS First-year Experience
EN601 108
Introduction to Programming Lab
EN601 226
Data Structures
EN601 230
Mathematical Foundations for Computer Science
EN601 270
Open Source Software Engineering (Semesters of Code I)
EN601 807
Teaching Practicum
EN601 749
Computational Genomics: Applied Comparative Genomics
EN601 765
Machine Learning: Linguistic & Sequence Modeling
EN601 769
Events Semantics in Theory and Practice
EN601 779
Machine Learning: Advanced Topics
EN601 780
Unsupervised Learning: From Big Data to Low-Dimensional Repr...
EN601 783
Vision as Bayesian Inference
EN601 787
Advanced Machine Learning: Machine Learning for Trustworthy...
EN601 801
Computer Science Seminar
EN601 803
Masters Research
EN601 805
Graduate Independent Study
EN601 743
Advanced Topics in Computer Security
EN601 808
Selected Topics in CS Education
EN601 809
PhD Research
EN601 814
Selected Topics in Computer Networks
EN601 817
Selected Topics in Systems Research
EN601 826
Selected Topics in Programming Languages
EN601 833
Seminar in Algorithms
EN601 856
Seminar: Medical Image Analysis
EN601 865
Selected Topics in Natural Language Processing
EN601 866
Selected Topics in Computational Semantics
EN601 875
Selected Topics in Machine Learning
EN601 503
Independent Study
EN601 457
Computer Graphics
EN601 461
Computer Vision
EN601 464
Artificial Intelligence
EN601 466
Information Retrieval and Web Agents
EN601 468
Machine Translation
EN601 475
Machine Learning
EN601 477
Causal Inference
EN601 482
Machine Learning: Deep Learning
EN601 490
Introduction to Human-Computer Interaction
EN601 496
Computer Integrated Surgery II - Teams
EN601 690
Introduction to Human-Computer Interaction
EN601 509
Computer Science Internship
EN601 519
Senior Honors Thesis
EN601 556
Senior Thesis in CIS
EN601 614
Computer Networks
EN601 617
Distributed Systems
EN601 618
Operating Systems
EN601 685
Probabilistic Models in the Visual Cortex
EN601 714
Advanced Computer Networks
EN601 723
Advanced Topics in Data-Intensive Computing
EN601 741
Advanced Topics in Secure and Censorship-Resistant Communica...
EN601 476
Machine Learning: Data to Models
EN601 444
Network Security
EN601 446
Sketching and Indexing for Sequences
EN601 448
Computational Genomics: Data Analysis
EN601 454
Augmented Reality
EN601 456
Computer Integrated Surgery II
EN601 459
Computational Geometry
EN601 463
Algorithms for Sensor-Based Robotics
EN601 465
Natural Language Processing
EN601 467
Introduction to Human Language Technology
EN601 474
ML: Learning Theory
EN601 441
Blockchains and Cryptocurrencies
EN601 481
Machine Learning: Optimization
EN601 486
Machine Learning: Artificial Intelligence System Design & De...
EN601 491
Human-Robot Interaction
EN601 501
Computer Science Workshop
EN601 507
Undergraduate Research
EN601 517
Group Undergraduate Research
EN601 520
Senior Honors Thesis
EN601 611
Computer Science Innovation & Entrepreneurship II
EN601 615
Databases
EN601 619
Cloud Computing
EN601 402
Digital Health and Biomedical Informatics
EN601 107
Introductory Programming in Java
EN601 220
Intermediate Programming
EN601 229
Computer System Fundamentals
EN601 231
Automata & Computation Theory
EN601 277
Disinformation Self-Defense
EN601 290
User Interfaces and Mobile Applications
EN601 310
Software for Resilient Communities
EN601 320
Parallel Programming
EN601 340
Web Security
EN601 356
Seminar: Computer Integrated Surgery II
EN601 620
Parallel Programming
EN601 414
Computer Networks
EN601 417
Distributed Systems
EN601 419
Cloud Computing
EN601 421
Object Oriented Software Engineering
EN601 424
Reliable Software Systems
EN601 427
Principles of Programming Languages II
EN601 429
Functional Programming in Software Engineering
EN601 433
Intro Algorithms
EN601 435
Approximation Algorithms
EN601 437
Federated Learning and Analytics
EN601 665
Natural Language Processing
EN601 647
Computational Genomics: Sequences
EN601 648
Computational Genomics: Data Analysis
EN601 654
Augmented Reality
EN601 655
Computer Integrated Surgery I
EN601 656
Computer Integrated Surgery II
EN601 657
Computer Graphics
EN601 659
Computational Geometry
EN601 661
Computer Vision
EN601 663
Algorithms for Sensor-Based Robotics
EN601 664
Artificial Intelligence
EN601 646
Sketching and Indexing for Sequences
EN601 666
Information Retrieval and Web Agents
EN601 667
Introduction to Human Language Technology
EN601 668
Machine Translation
EN601 674
ML: Learning Theory
EN601 675
Machine Learning
EN601 676
Machine Learning: Data to Models
EN601 677
Causal Inference
EN601 681
Machine Learning: Optimization
EN601 682
Machine Learning: Deep Learning
EN601 686
Machine Learning: Artificial Intelligence System Design & De...
EN601 634
Randomized and Big Data Algorithms
EN601 621
Object Oriented Software Engineering
EN601 622
Software Testing & Debugging
EN601 624
Reliable Software Systems
EN601 626
Principles of Programming Languages
EN601 627
Principles of Programming Languages II
EN601 628
Compilers & Interpreters
EN601 629
Functional Programming in Software Engineering
EN601 630
Combinatorics & Graph Theory in Computer Science
EN601 631
Theory of Computation
EN601 633
Intro Algorithms
EN601 104
Computer Ethics
EN601 635
Approximation Algorithms
EN601 636
Algorithmic Game Theory
EN601 637
Federated Learning and Analytics
EN601 640
Web Security
EN601 641
Blockchains and Cryptocurrencies
EN601 642
Modern Cryptography
EN601 643
Security & Privacy in Computing
EN601 644
Network Security
EN601 645
Practical Cryptographic Systems