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এই পরীক্ষায় এই টপিক থেকে ২টি প্রশ্ন — MRI ও Algorithm vs hardware।
বিকল্প: (ক) X-ray (CT) • (খ) Sound wave (USG) • (গ) শক্তিশালী চুম্বক + রেডিও তরঙ্গ ✓ • (ঘ) গামা-রে (PET)
MRI = Magnetic Resonance Imaging — শক্তিশালী magnetic field (1.5-3 Tesla) + radio frequency pulse → শরীরের পানির hydrogen-এর nuclear spin মাপা।
| Technique | Principle | Radiation | Best for | Examples |
|---|---|---|---|---|
| X-ray | EM wave (X-band) | আছে (ionizing) | Bones, lungs | Chest X-ray |
| CT Scan | Multi-angle X-ray | আছে | 3D bone/organ | Brain scan, abdomen |
| MRI | Magnet + RF | নেই | Soft tissue (brain, muscle, ligament) | Brain MRI, knee |
| Ultrasound | High-freq sound (>20 kHz) | নেই | Soft tissue, pregnancy | Fetal scan, gallbladder |
| PET | Radioactive tracer + gamma | আছে | Metabolism, cancer | Cancer staging |
| SPECT | Single-photon gamma | আছে | Functional imaging | Cardiac |
| Mammography | Low-energy X-ray | আছে | Breast | Screening |
| Endoscopy | Optical camera | নেই | Internal cavity | GI tract |
| Invention | আবিষ্কারক | বছর |
|---|---|---|
| Stethoscope | René Laennec | 1816 |
| Thermometer | Galileo (improved Daniel G. Fahrenheit) | 1612 |
| X-ray | Wilhelm Röntgen (Nobel 1901) | 1895 |
| ECG | Willem Einthoven (Nobel 1924) | 1903 |
| Insulin | Banting & Best | 1921 |
| Penicillin | Alexander Fleming (Nobel 1945) | 1928 |
| CT Scan | Hounsfield & Cormack (Nobel 1979) | 1971 |
| MRI | Lauterbur & Mansfield (Nobel 2003) | 1977 |
| Ultrasonography | Ian Donald | 1956 |
| DNA structure | Watson, Crick, Franklin (Nobel 1962) | 1953 |
বিকল্প: (ক) Asymptotically faster algorithm ✓ • (খ) PC config উন্নত • (গ) Fast I/O • (ঘ) ক+গ
Algorithm-এর asymptotic complexity (Big-O) উন্নত করা = orders of magnitude speedup। Hardware upgrade দেয় মাত্র ২-১০× speedup।
| Big-O | নাম | উদাহরণ Algorithm | n=1,000,000 (operations) |
|---|---|---|---|
| O(1) | Constant | Hash table lookup | 1 |
| O(log n) | Logarithmic | Binary search | 20 |
| O(n) | Linear | Linear search | 1,000,000 |
| O(n log n) | Linearithmic | Merge sort, Heap sort | 20,000,000 |
| O(n²) | Quadratic | Bubble sort, Selection sort | 10¹² |
| O(n³) | Cubic | Naive matrix multiplication | 10¹⁸ |
| O(2ⁿ) | Exponential | Brute force traveling salesman | overflow |
| O(n!) | Factorial | Permutation enumeration | overflow |
১০ লক্ষ items sort করতে:
Hardware এত speed দিতে পারে না।
| Method | Speedup |
|---|---|
| Algorithm improvement | 10× – 10,000,000× |
| Data structure choice | 10× – 1000× |
| Caching/Memoization | 2× – 100× |
| Parallelization | 2× – n× (n = cores) |
| CPU upgrade | 1.5× – 3× |
| More RAM | (eliminates swapping) |
| SSD vs HDD | 5× – 10× (I/O bound) |
| GPU acceleration | 10× – 1000× (parallel tasks) |
| Algorithm | Use | Inventor |
|---|---|---|
| Euclidean | GCD | Euclid (~300 BCE) |
| Newton's method | Root finding | Newton |
| FFT | Fast Fourier Transform | Cooley-Tukey (1965) |
| Quicksort | Sorting | Tony Hoare (1959) |
| Dijkstra | Shortest path | Edsger Dijkstra (1956) |
| PageRank | Web search ranking | Larry Page, Sergey Brin (1998) |
| Backpropagation | Neural network training | Werbos, Rumelhart |
| Tech | বিবরণ | উদাহরণ |
|---|---|---|
| AI | Artificial Intelligence | ChatGPT, AlphaGo, Siri |
| ML | Machine Learning | Recommendation systems |
| Deep Learning | Multi-layer neural networks | Image recognition, NLP |
| Robotics | Autonomous machines | Boston Dynamics, surgical robots |
| Drones (UAV) | Unmanned aerial vehicles | Delivery, surveillance |
| IoT | Internet of Things | Smart home, sensors |
| AR/VR/MR | Augmented/Virtual/Mixed Reality | Oculus, HoloLens |
| 3D Printing | Additive manufacturing | Prosthetics, prototyping |
| Quantum Computing | Quantum bits (qubits) | Google Sycamore, IBM Q |
| Blockchain | Distributed ledger | Bitcoin, smart contracts |
| CRISPR | Gene editing | Disease treatment |
| Self-driving | Autonomous vehicles | Tesla, Waymo |
| Satellite | দেশ/সংস্থা | বছর | উদ্দেশ্য |
|---|---|---|---|
| Sputnik 1 | USSR | 1957 | First man-made satellite |
| Explorer 1 | USA | 1958 | First US satellite |
| INSAT, Aryabhatta | India | 1975 | India's first |
| BS-1 | Bangladesh | 2018 | Communication |
| ISS (International Space Station) | Multi-nation | 1998-present | Manned space lab |
| Hubble | USA | 1990 | UV/Visible telescope |
| JWST | USA/ESA/CSA | 2021 | IR telescope |
আধুনিক প্রযুক্তি — AI, Robotics, Satellite — মূল লেকচার শিট — সব medical imaging tech (X-ray/CT/MRI/USG/PET/SPECT) বিস্তারিত, AI/ML/Deep Learning, Robotics ও drones, Satellite types (LEO/MEO/GEO/Geostationary), Bangabandhu Satellite ও বাংলাদেশের space program, Big-O complexity ও important algorithms, Quantum computing basics, 3D printing, Blockchain ও cryptocurrency।