Italy Secondaria di secondo grado – classe 5ª (esame di Stato) Computer science

1. Computation, networks and simulation

Numerical computation and theory · Networks · Scientific simulation

• Numerical Methods: Finding Roots and Areas Step by Step – Some equations and areas cannot be found with a neat formula. Numerical methods get as close as we like with simple repeated steps: check a change of sign, halve the interval (bisection), slide down tangents (Newton-Raphson), repeat x = g(x) (fixed-point iteration), add up trapeziums for an area, and walk along a slope in small steps (Euler).
• Computer Networks and How the Internet Works – A network is a group of devices linked to share data. Each device has an IP address. Data is cut into numbered packets. Routers pass each packet hop by hop towards its address, and TCP puts the packets back in order. DNS turns a website name into an IP address. Clients ask, servers answer. Firewalls, passwords, updates and encryption keep a network safe.
• How Networks Grew and How Data Travels – A computer network is a group of connected devices that share data. Networking began with ARPANET (1969), grew into NSFNET (1980s) for universities, and joined with other networks to become the Internet, a network of networks. Every data communication has five parts: sender, receiver, message, communication media and protocol. Bandwidth is the range of frequencies a channel can carry (in Hz); data rate is how many bits travel per second (bps). Every device on a network has an IP address. Data can move by circuit switching (a fixed path is booked first) or packet switching (data is cut into packets that travel on their own).
• Computer Simulation – A model is a simplified description of a real system that keeps only what matters. A computer simulation runs that model step by step in time to see what would happen. It has variables (the state), rules (how the state changes), parameters (numbers we can set) and often randomness, so we repeat runs and average. We check a simulation against real data (validation). Simulations are used for weather, traffic, disease spread, flight training and design, because they are cheaper, safer and faster than real tests, but they are only as good as their model and data.