CHAIRMAN HIGH INTEGRITYSYSTEMS Mr. Matthias Wagner
Professor and ProjectMentor Mr. Gerd Doeben-Henisch
REAL TIME OPERATINGSYSTEMS A Real Time Operating System areintended for real-time applications. A key characteristic of RTOS is the levelof its consistency concerning theamount of time it takes to accept andcomplete an application´s task.
Real Time Computing In Computer Science, Real-timecomputing or Reactive computing is thestudy of hardware and software systemsthat are subject to a ´real-timeconstraint´. A Real-time system is the system whereits application can be considered to bemission critical. So, a real-time deadline must bemet, regardless of its system load.
AIR TRAFFIC CONTROL Air traffic control (ATC) is a serviceprovided by ground-based controllerswho direct aircraft on the ground and inthe air. The primary purpose of ATC systemsworldwide is to separate aircraft toprevent collisions, to organize andexpedite the flow of traffic, and toprovide information and other supportfor pilots when able.
Modes of Air Traffic Control There are two types of controls that areexercised by the Air Traffic ControlSystems : 1. Air Control 2. Ground Control
1. Air Control : The primary method of controlling theimmediate airport environment is visualobservation from the Airport TrafficControl Tower (ATCT) The ATCT is a tall, windowed structurelocated on the airport grounds. Generally planes in air are having morepriority than on ground due to hazards.
2. Ground Control Ground Control is responsible for theairport "movement" areas, as well asareas not released to the airlines orother users. Ground Control is vital to the smoothoperation of the airport, because thisposition impacts the sequencing ofdeparture aircraft, affecting the safetyand efficiency of the airports operation.
Usage of V-Model in our Project: Our whole project is based on the V-Modelprocess model as we begin with theexploration of the Requirement Analysisfollowed by our proposed Architecturaldesign which is then followed by theTechnical Blueprint of our design to beimplemented. After the analysis part is finished, thedesigning part commences wherein thecoding part is divided into several units andthe coding is carried out for these units.
Usage of V-Model in our Project: After the coding part is done overwith, the testing part begins and we testand debug the code for each unit, .i.e.the Unit Testing takes place and aftereach unit is successfully tested andmaintained. The System Integration then takes placewherein we integrate all the units andthen test the system as a whole.
Usage of V-Model in our Project: This process of System testing andmaintaining is carried out several timesand after getting rid of every possibleloophole and implementing the ideassuccessfully, the project is affirmativewith respect to the implementation of theV- Process Model.
Plan of Action for the firstproject report : Gathering required informationregarding project, e.g. runwaysinformation , flight`s speed, height,distance information. Analyzing the practical result against thedesired result with time as a constraint. Selecting the platform for thedevelopment of project. E.g. java or .netor C , C++ etc.
Plan of action during thesecond project report :Runways : One of the most important aspect of theproject was the selection of the mostappropriate runway and these are thetypes which were at my disposal :1. Asterisk Runway : Handling of planeswas possible from every possible direction.2. Plus Runway : Handling of planes ispossible from 4 directions.3. Horizontal-T Runway : Quick arrivals anddepartures become easy.
Eventual Result (ProjectReport 2) : The type of runway that we opted forresembled much to the “HORIZONTAL T-RUNWAY” but not exact. The reason being that the first two aremore appropriate for scenarios where thereare many number of planes in operationand also all the directions are available.But due to time constraints, we had to limitour project and with limited operations therunway resembling the „T‟ was much moresuited to our purpose.
Plan of Action for ThirdProject Report : The task that we had to accomplish was the mostimportant aspect in quest of taking the first big steptowards implementation of the ideas wherein we hadto do the designing of the technical blueprint of theproject. We gathered all the details and information and byselecting the most important points representedthem on paper using which as a source, a graphicalrepresentation was designed in a GUI (GraphicalUser Interface ) environment which in our case wasthe Net Beans on Java so as to get the first realpicture of the project .
Plan of Action for FourthProject Report : This time we needed to construct thescheduler for the project. In the previousproject reports we had discussed thescenarios involving 8 planes ,6 planesas well as 4 planes.
Eventual Result (ProjectReport 4) : As the number of planes were increasing thescenarios with it also increased exponentiallyand as there was always the time constraint asa significant matter, we had to select thenumber of planes using which we coulddemonstrate our project successfully. Finally after going through all the pros andcons and also considering the fact that theprobability of errors creeping in would increasewith the increase in the scenario, we finalizedthe number of planes that would be handledas 4 wherein 2 two planes would be on theground and 2 in the air.
Plan of Action for ProjectReport 5 : the coding part was initiated during theseweeks where the time constraint was keptin mind. The coding part was divided intodifferent units and code was written foreach unit and then tested with respect tothe actual project. What was also worked upon was thecontrolling of the landing and takeoff of theplanes from the specified directions so asto divert the planes in case of delayedlanding or takeoff and if the runway is busy.
Eventual Result ( ProjectReport 5) : The design of the movement of planes wasdone using the JDK Net Beans 6.8 whereinwe used the AWT components like theJPanel and JFrame and methods likeFillOval, DrawLine,etc as a transmitter inthe project. Also the “Screen Display” was designedusing the same methodoligies and tools asmentioned above wherein the input valuescould be given and the result would bedisplayed depending on those values.
Compliance of our ATCProject with RTS withDiagram and Descriptions :
Notations : Gamma (Ґ) = Set of Tasks. T.T = combines the event(E) with task gamma (Ґ), then task isactivated and put into que(Q). Q = set of all tasks which should be processed at a certain pointof time. Sched = gets as input the set of ‘Q’(the tasks in Q), then‘sched’ clears the ordering and puts the task in Q* priority wise. Pie (π) = Set of rules about priority of tasks. DM=Deadline Monotonic-Di<Dj ,then π i> π j, i.e. if the deadlineof i is smaller than j, then the priority of i is greater than j, where D is the relativedeadline and π is the priority. EDF = Earliest Deadline First. RR = Resource Rule : If a task is writing in a critical resource, itcan‟t be stopped or interrupted anyhow. E(events) = the events in our project our when the pilot asks thecontrollers.
Notations : For eg- 1)Should I land? 2)Should I take off? Task = Our prime task in here in this project is to make sure that air traffic is controlledwithout any mishappening even in adverse conditions efficiently. The planes that are inair should be provided runaway as soon as possible according to its deadline and theplane ready to take off, should be given proper space to take off efficiently. Then the E(event) is combined with Tasks. Set of priority rules = The priority rules according to our project are given below : 1) The maximum priority is given to the plane with shortest deadline. 2) Then the planes to be landed are given priority over the planes that have to take off. 3) In case we don‟t consider any plane landing then the priority to the plane from theplanes ready to take off is given according to the given input.
Notations : EDF = Earliest Deadline First : We followed thiscriteria and is set in the input window. Input is givenaccording to the current situation based on alreadyconcluded decision that which plane needs to be landedfirst or which can wait for sometime according to thedeadline of the respective plane. So the sequence in theinput window follows the EDF rule of RTS. RR = Resource Rule : This rule is also being followedand once the input has been given according to thedeadlines of respective planes and once our schedulerstarts working, i.e. our processes of landing the planes ortake off has started writing in the critical resource, itshouldn‟t be and can‟t be interrupted anyhow. In the end when the given task are being completed oneby one, „RESPONSE‟ is being displayed showing thestatus of the processes, which are completed.
Description : We begin by proving our authorization as it is acritical system and then start by giving the inputswhere we enter the number of planes for which wewant to see the result where the limit is a maximumof 4 planes from where on we specify the number ofplanes that are on ground and in air with both thescenarios having a limit as 2 planes. Now we specify the direction of either(North, South, East, West) for each of the planes. After all the inputs have been given, the executionpart starts where the movement of the plane isdisplayed and the highest priority is given to theplane which has been specified as the first plane.
Description : Similarly the priority is specified for eachplane in the order of which they areselected. The Receiver window then pops up and thecurrent status of the plane is displayed alsowith its graphical representation where Y-axis represent No of planes and X-axis thetime,and we can view the status of theother planes as well and then by clickingon Exit, we are logged out of the session.
Description : In our example, we have shown theworst case scenario that we haveconsidered in our project, i.e. maximum4 number of planes (2 in air ready forlanding and 2 on ground waiting for takeoff). They are being set in our input windowand now we have to control theirrespective processes.
Notations : L1 = Plane that has to be landed firstfrom north to south(maximumpriority/shorter deadline). L2 = Plane that has a bit less prioritythan L1 and has to be landed second. T1 = Plane ready to take off first asrunway is free. T2 = Plane to take off after landing ofL1.
Notation descriptions : The basic steps that are executed when we handle ourscenario are as follows : 1) L2 was scheduled to land on runway no. 3 (i.e. fromnorth to south), but L1 was having more priority, i.e. shortdeadline, so L1 was given the runway and L2 is beingasked to land from east to west i. e. runway no. 2. 2) L1 lands on runway 3 and L2 moves on the easternside. 3) After L1 lands and the runway is clear, T2 plane isbeing asked to take off from 3. 4) In the mean time, L2 turns around from 3(north) to landfrom 2(i.e. east to west) the plane waiting there T1 takesoff and the runway is clear for L2 to land safely. So according to the set of priority rules, different taskswere completed.
Hazard Analysis : A hazard analysis is a process used toassess risk. The results of a hazard analysis is theidentification of unacceptable risks and theselection of means of controlling oreliminating them. An analysis or identification of the hazardswhich could occur at each step in theprocess, and a description andimplementation of the measures to betaken for their control.
Software Specification : Environment used : Java (JDK1.6), Java NetBeans Version 6.8. Operating System : Windows XP, Vista.
Significance of Simulation ofAir Traffic Control Project : 1. This simulation of ATC considers andsatisfies all the 4 directions successfully for theplanes in the air, .i.e. for the planes preparingto land. 2. This simulation of ATC considers andsatisfies all the 4 positions successfully for theplanes on the ground, .i.e. for the planespreparing for take-off. 3. This simulation of ATC functionssuccessfully without any collisions and itoperates in such a way that the chances ofany collision taking place nullifies.
Significance of Simulation ofAir Traffic Control Project : 4. This simulation of ATC prioritizes byusing the Earliest Deadline First (EDF)where in the one with the nearest deadlineis given the highest priority. 5. This simulation of ATC successfullymaintains the exchange of instructions andsignals between the ATC Controller and theFlight Crew. 6. This simulation of ATC successfully satisfies allthe priorities that have to be considered during theLanding and Takeoff scenarios.