Real-Time Auditing & Defense

• Introduction to Real-Time Audit and Defense
• Presented by Dr. Ahmed Elngar, Associate Professor and Head of Computer Science Department at Beni-Suef University, and Faculty at the American University in the Emirates.

Course Syllabus

• Course: Real-Time Auditing & Defense (UCCE 3223)
• Credit hours: 3 (2 hours of theory and 2 hours of practical/tutorials)
• Prerequisite: UCCS 3107
• Course description covers definitions, applications, hard vs soft real time systems, reference models, and common scheduling approaches.
• Scheduling topics include clock-driven, priority-driven, periodic/sporadic tasks, multiprocessor scheduling, resource access control, flexible computations, temporal distance constraints, and real-time communication/programming.

Textbook

• The primary textbook is "R. Mall, Real-Time Systems, Pearson, 2008".
• Includes handouts with the textbook.

Course Plan

• Introduction to Real-Time Auditing & Defense topics
• Task Scheduling: Uniprocessors and Multiprocessors
• Commercial Real-Time Operating Systems
• Real-time communications
• Real-time databases.

Reference Books

• Jane Liu, Real-Time Systems, Pearson, 2000
• C. Krishna and K. Shin, Real-Time Systems, McGraw-Hill, 2000

Introduction to Embedded Systems

• Embedded systems are increasingly being used in newer applications.
• Embedded systems are usually real-time in nature.
• There are more processors deployed in real-time applications than total processors manufactured worldwide.

Surge in Embedded Applications is Due to

• Trend of reducing costs of computers
• Processors and Memory
• Flexibility due to the Internet.
• Reducing power consumption.
• Reducing size.
• Increased processing power.
• Greater hardware and software reliability.

Real-Time Definition

• Quantitative time notion using a physical clock.
• Example: Coolant shower action must complete within 100ms when temperature exceeds 500 degrees.
• Different from qualitative time notions like before, after, sometime, and eventually.

Embedded System Applications in Different Areas

• In industry for Chemical plant control and Automated car assembly plants. Supervisory Control And Data Acquisition(SCADA).
• In medicine for recovery of Displaced Radioactive Material and Medical equipments.
• As Peripheral Equipments such as a Laser Printer, digital cameras and camcorders, sensors.
• In Transportation of Multi-Point Fuel Injection (MPFI) System and Automated cars.

Embedded System Applications in Other Technological Arenas

• Telecommunication applications. Cellular Systems.
• Aerospace. Computer On-board an Aircraft.
• Internet. Multimedia Applications for Video Conferencing.
• Consumer Electronics include Cell Phones, digital cameras, and camcorders.
• Defense Applications include Missile Guidance Systems.

Example of Automotive Applications

• Approximately 100 processors are utilized per car
• Applications include engine control, break system, and air bag deployment
• BMW 745i has 2,000,000 Lines of Code, running on Window CE OS, using over 60 microprocessors
• Contains 53 8-bit, 11 32-bit, and 7 16-bit processors multiple networks

ECUs (Engine Control Units)

• ECU, Airbag Module, Body Controller
• Driver's Door Module, Cruise Control module
• Instrument Panel, Climate Control Module
• ABS Module, Transmission Controller
• Power Distribution Box Module

Automotive Embedded Systems

• Fuel injection and cruise control
• Antilock brakes
• Air bags
• Keyless entry
• Climate control
• GPS

MPFI: Multi-Point Fuel Injection

• Controls the timing and amount of fuel injected
• Receives signals from various sensors
• Processes the signals
• Sends control signals to the actuators

Cruise Control

• Designed to maintain a vehicle's speed at a constant rate
• Example of maintaining the speed at 60kmph
• The computer checks the vehicle speed at a frequency that is preset, and it is called the control rate.
• To function, the computer computes a deviation from the desired speed and takes corrective action.

Reactive System

• Every embedded system Responds to inputs (events).
• Events often occur due to changes to the environment.
• Responses are called actions.
• Embedded systems can be described as responses to events.

Types of Events

• Periodic: Occurs according to a timer.
• Vast majority of activities for small systems are periodic.
• Sporadic: Occurs statistically or randomly.
• Aperiodic: Sporadic but multiple can occur together.

Specifying an Embedded System

• Model all events and actions.
• Complex systems: May have thousands of event and action types.
• Complex systems: Modeled in terms of subsystems.

Laser Printer - Example of Peripheral equipment

• Uses A horizontal strip of dots across a page known as a Raster line
• Created by a raster image processor
• A laser beam neutralizes the charge on the black parts of the image
• Leaves a static electric negative image on the photoreceptor surface

Mobile Phone

• Tasks for the processor: convert input voice to digital using DSP, convert digital voice to CDMA signals, convert incoming CDMA signals to microphone signals
• Handle control channel signals, Handle user invoked functions.

SCADA

• Supervisory Control and Data Acquisition
• SCADA is a computer system monitoring and controlling an ongoing process.
• Sensors store process data in a distributed real-time database
• The Supervisory system issues a control signal.
• SCADA is utilized for Energy Management Systems.

Computer On-board an Aircraft is Considered an Embedded System

• Periodically samples velocity, acceleration, and altitude.
• Computes current position (X,Y,Z position).
• Computes deviation from the trajectory.
• Drives actuators to take corrective actions.
• High performance is required since Task deadlines in few micro to milliseconds.

Anti-Missile System

• Designed to sense a target and home onto it based on thermal or electrical characteristics
• Designed to carry out track corrections based on target trajectory.
• Sampling and processing activities need to be completed in a few micro or milliseconds to be effective.

Key Question

• The fundamental question is why use software and operating systems in embedded systems instead of implementing all functionalities in hardware, since there are a limited set of functionalities.

Key Recent Trends

• Increasing computation demands due to video conferencing and MobileTV.
• Increasingly networked due to the prevalence of Remote monitoring/debugging devices and Embedded web browser.
• e.g. Mercedes car with web browser.
• Cameras and disks sit directly on networks
• There is an Increasing need for reducing time-to-market under ever changing standards!
• There must be careful co-design of hardware and software!

Basic Model of an Embedded System

• Includes sensor, input conditioning unit, input interface, real-time computer, human-computer interface, output interface, output conditioning unit, and actuator, with operators interacting via the human-computer interface.

Real-Time Applications

• Many real-time systems are control systems
• A simple one-sensor, one-actuator control system may be used
• Reference input r(t) is input to A/D component, then to a control-law computation component yk
• This is input to D/A before sending to an actuator to manage a plant
• The system being controlled outputs to a sensor which sends input to the A/D component

Simple Control System (cont'd)

• Pseudo-code for a system may involve setting a timer to interrupt periodically with period T
• Set timer interrupt at each timer interrupt.
• Perform analog-to-digital conversion to get y, and compute the control output u
• Output u and do digital-to-analog conversion;
• T is called the sampling period.
• T is a key design choice; typical range: seconds to milliseconds.

Multi-rate Control Systems

• Use multiple sensors and actuators and must support control loops of different rates, such as in Helicopter flight controllers.
• Examples include validating sensor data and selecting data sources in each 1/180-sec cycle.
• Some systems perform keyboard input and mode selection every sixth cycle.
• Harmonic rates simplify the system when used.

Hierarchical Control Systems

• In air traffic-flight control hierarchies, operator system interfaces provides responses to the system, and controls operator commands in real-time
• Sampling rates can vay from Minutes to hours

Signal-Processing Systems transform data from one form to another.

• Applications include digital filtering, video and voice compression/decompression, and radar signal processing.
• Response times range from milliseconds to seconds.

Signal Processing Systems - Radars as an Example

• Use radar
• Use sampled digitized data
• Utilize memory
• Track records
• Digital signal processors
• Data processor
• Signal processing parameters
• Control Status

Types of Sensors

• A sensor converts some physical characteristic of its environment into electrical signals.
• A photo-voltaic cell converts light energy into electrical energy.
• A temperature sensor typically operates based on the principle of a thermocouple.
• A pressure sensor typically operates based on the piezoelectricity principle.

Low Cost Sensors

• IR proximity, shaft encoder, GPS, Sonar, IR distance, Electronic Compass, CMOS Camera.

Actuators

• An actuator converts electrical signals from a computer into some physical actions.
• The physical actions may be: Motion, change of thermal, electrical, pneumatic, or physical characteristics of some objects.
• Example actuators include motors, heaters, and hydraulic and pneumatic actuators.

Low Cost Servos

• A Servo is a small wireless device that has a shaft.
• The shaft can be positioned at specific angular positions by sending a coded signal.

Servo

• A servo maintains the angular position of its shaft as long as a coded signal exists on the input line
• The angular position of the shaft changes if the coded signal changes.
• Servos are used predominantly in robots and radio controlled cars, and puppets.

Signal Conditioning

• Analog signals are generated by a sensor
• Photo-voltaic cell normally generates signals in the millivolts range.
• The generated signals need to be conditioned before they can be processed by a computer.
• Important types of conditioning include Voltage Amplification and Voltage Level Shifting.
• Also include Frequency Range Shifting and Filtering and Signal Mode Conversion,

ADC and DAC

• An analog-to-digital converter (ADC) Converts continuous signals to discrete digital numbers.
• The reverse operation is Performed by a digital-to-analog converter (DAC).

Summary of Real Time

• A system is said to be real-time when quantitative expressions of time are necessary to describe the behavior of the system.
• A real-time task is one that is associated with some time constraints.
• A real-time task is classified into either hard, firm, or soft real-time type depending on the consequences of a task failing to meet its timing constraints.
• A safety-critical system is one which does not have a fail-safe state and any failure of the system can cause severe damage.
• Many hard real-time systems are safety-critical in nature
• The typical characteristic features of a hard real-time system include embedded, feedback and distributed structure, and safety-criticality.
• It is possible though that some hard real-time systems may not have these features.

Research Group

• The Scientific Innovation Research Group (SIRG) aims to evaluate IOT performance and propose a secure architecture for IoT security issues in education.