diff --git a/projects/Assignments/homework3/Sasala_HW3_Screenshots.pdf b/projects/Assignments/homework3/Sasala_HW3_Screenshots.pdf
new file mode 100644
index 0000000000000000000000000000000000000000..49d03e35f7783db967736bbb1ed2072a60c1aba6
Binary files /dev/null and b/projects/Assignments/homework3/Sasala_HW3_Screenshots.pdf differ
diff --git a/projects/Assignments/homework3/Sasala_OpenDisEspduSender1.java b/projects/Assignments/homework3/Sasala_OpenDisEspduSender1.java
new file mode 100644
index 0000000000000000000000000000000000000000..fbe926fb1529c0b09dc730487e983d7d8e736a59
--- /dev/null
+++ b/projects/Assignments/homework3/Sasala_OpenDisEspduSender1.java
@@ -0,0 +1,297 @@
+// package edu.nps.moves.examples; // copy example from OpenDIS distribution, modify to serve as template
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+
+import edu.nps.moves.dis.*;
+import edu.nps.moves.disutil.DisTime;
+
+/**
+ * Creates and sends ESPDUs in IEEE binary format.
+ *
+ * @author DMcG
+ */
+public class Sasala_OpenDisEspduSender1
+{
+ public static final int NUMBER_TO_SEND = 5000;
+
+ public enum NetworkMode{UNICAST, MULTICAST, BROADCAST};
+
+ /** Default multicast group address we send on */
+ public static final String DEFAULT_MULTICAST_GROUP="239.1.2.3";
+
+ /** Default port we send on */
+ public static final int DIS_DESTINATION_PORT = 3000;
+
+/** Possible system properties, passed in via -Dattr=val
+ * networkMode: unicast, broadcast, multicast
+ * destinationIp: where to send the packet. If in multicast mode, this can be multicast.
+ * To determine broadcast destination IP, use an online broadcast address
+ * calculator, for example http://www.remotemonitoringsystems.ca/broadcast.php
+ * If in multicast mode, a join() will be done on the multicast address.
+ * port: port used for both source and destination.
+ * @param args
+ */
+public static void main(String args[])
+{
+ /** an entity state pdu */
+ EntityStatePdu espdu = new EntityStatePdu();
+ MulticastSocket socket = null; // must be initialized, even if null
+ DisTime disTime = DisTime.getInstance(); // TODO explain
+ int alternator = -1;
+
+ // ICBM coordinates for my office
+ double radians = 0;
+
+ // Default settings. These are used if no system properties are set.
+ // If system properties are passed in, these are over ridden.
+ int port = DIS_DESTINATION_PORT;
+ NetworkMode mode = NetworkMode.BROADCAST;
+ InetAddress destinationIp = null; // must be initialized, even if null
+
+ try
+ {
+ destinationIp = InetAddress.getByName(DEFAULT_MULTICAST_GROUP);
+ }
+ catch(UnknownHostException e)
+ {
+ System.out.println(e + " Cannot create multicast address");
+ System.exit(0);
+ }
+
+ // All system properties, passed in on the command line via -Dattribute=value
+ Properties systemProperties = System.getProperties();
+
+ // IP address we send to
+ String destinationIpString = systemProperties.getProperty("destinationIp");
+
+ // Port we send to, and local port we open the socket on
+ String portString = systemProperties.getProperty("port");
+
+ // Network mode: unicast, multicast, broadcast
+ String networkModeString = systemProperties.getProperty("networkMode"); // unicast or multicast or broadcast
+
+ // Set up a socket to send information
+ try
+ {
+ // Port we send to
+ if(portString != null)
+ port = Integer.parseInt(portString);
+
+ socket = new MulticastSocket(port);
+
+ // Where we send packets to, the destination IP address
+ if(destinationIpString != null)
+ {
+ destinationIp = InetAddress.getByName(destinationIpString);
+ }
+
+ // Type of transport: unicast, broadcast, or multicast
+ // TODO convert to String constants
+ if(networkModeString != null)
+ {
+ if(networkModeString.equalsIgnoreCase("unicast"))
+ mode = NetworkMode.UNICAST;
+ else if(networkModeString.equalsIgnoreCase("broadcast"))
+ mode = NetworkMode.BROADCAST;
+ else if(networkModeString.equalsIgnoreCase("multicast"))
+ {
+ mode = NetworkMode.MULTICAST;
+ if(!destinationIp.isMulticastAddress())
+ {
+ throw new RuntimeException("Sending to multicast address, but destination address " + destinationIp.toString() + "is not multicast");
+ }
+
+ socket.joinGroup(destinationIp);
+ }
+ } // end networkModeString
+ }
+ catch(IOException | RuntimeException e)
+ {
+ System.out.println("Unable to initialize networking. Exiting.");
+ System.out.println(e);
+ System.exit(-1);
+ }
+
+ // Initialize values in the Entity State PDU object. The exercise ID is
+ // a way to differentiate between different virtual worlds on one network.
+ // Note that some values (such as the PDU type and PDU family) are set
+ // automatically when you create the ESPDU.
+ espdu.setExerciseID((short)1);
+
+ // The EID is the unique identifier for objects in the world. This
+ // EID should match up with the ID for the object specified in the
+ // VMRL/x3d/virtual world.
+ EntityID entityID = espdu.getEntityID();
+ entityID.setSite(1); // 0 is apparently not a valid site number, per the spec
+ entityID.setApplication(1);
+ entityID.setEntity(2);
+
+ // Set the entity type. SISO has a big list of enumerations, so that by
+ // specifying various numbers we can say this is an M1A2 American tank,
+ // the USS Enterprise, and so on. We'll make this a tank. There is a
+ // separate project elsehwhere in this project that implements DIS
+ // enumerations in C++ and Java, but to keep things simple we just use
+ // numbers here.
+ EntityType entityType = espdu.getEntityType();
+ entityType.setEntityKind((short)1); // Platform (vs lifeform, munition, sensor, etc.)
+ entityType.setCountry(225); // USA
+ entityType.setDomain((short)1); // Land (vs air, surface, subsurface, space)
+ entityType.setCategory((short)1); // Tank
+ entityType.setSubcategory((short)1); // M1 Abrams
+ entityType.setSpec((short)3); // M1A2 Abrams
+
+ Set<InetAddress> broadcastAddresses;
+ // Loop through sending N ESPDUs
+ try
+ {
+ System.out.println("Sending " + NUMBER_TO_SEND + " ESPDU packets to " + destinationIp.toString());
+ for(int idx = 0; idx < NUMBER_TO_SEND; idx++)
+ {
+ // DIS time is a pain in the ass. DIS time units are 2^31-1 units per
+ // hour, and time is set to DIS time units from the top of the hour.
+ // This means that if you start sending just before the top of the hour
+ // the time units can roll over to zero as you are sending. The receivers
+ // (escpecially homegrown ones) are often not able to detect rollover
+ // and may start discarding packets as dupes or out of order. We use
+ // an NPS timestamp here, hundredths of a second since the start of the
+ // year. The DIS standard for time is often ignored in the wild; I've seen
+ // people use Unix time (seconds since 1970) and more. Or you can
+ // just stuff idx into the timestamp field to get something that is monotonically
+ // increasing.
+
+ // Note that timestamp is used to detect duplicate and out of order packets.
+ // That means if you DON'T change the timestamp, many implementations will simply
+ // discard subsequent packets that have an identical timestamp. Also, if they
+ // receive a PDU with an timestamp lower than the last one they received, they
+ // may discard it as an earlier, out-of-order PDU. So it is a good idea to
+ // update the timestamp on ALL packets sent.
+
+
+ // An alterative approach: actually follow the standard. It's a crazy concept,
+ // but it might just work.
+ int timestamp = disTime.getDisAbsoluteTimestamp();
+ espdu.setTimestamp(timestamp);
+
+ // Set the position of the entity in the world. DIS uses a cartesian
+ // coordinate system with the origin at the center of the earth, the x
+ // axis out at the equator and prime meridian, y out at the equator and
+ // 90 deg east, and z up and out the north pole. To place an object on
+ // the earth's surface you also need a model for the shape of the earth
+ // (it's not a sphere.) All the fancy math necessary to do this is in
+ // the SEDRIS SRM package. There are also some one-off formulas for
+ // doing conversions from, for example, lat/lon/altitude to DIS coordinates.
+ // Here we use those one-off formulas.
+
+ radians = (radians + (Math.PI/6)) % (2*Math.PI);
+
+ Vector3Double location = espdu.getEntityLocation();
+ location.setX(Math.cos(radians)*1000);
+ location.setY(Math.sin(radians)*1000);
+ location.setZ(250);
+
+ // Optionally, we can do some rotation of the entity
+
+ Orientation orientation = espdu.getEntityOrientation();
+ orientation.setTheta((float)(radians + (Math.PI/2))%(float)(Math.PI *2));
+
+ // You can set other ESPDU values here, such as the velocity, acceleration,
+ // and so on.
+
+ // Marshal out the espdu object to a byte array, then send a datagram
+ // packet with that data in it.
+ ByteArrayOutputStream baos = new ByteArrayOutputStream();
+ DataOutputStream dos = new DataOutputStream(baos);
+ espdu.marshal(dos);
+
+ FirePdu fire = new FirePdu();
+ byte[] fireArray = fire.marshal();
+
+ // The byte array here is the packet in DIS format. We put that into a
+ // datagram and send it.
+ byte[] data = baos.toByteArray();
+
+ broadcastAddresses = getBroadcastAddresses();
+ Iterator it = broadcastAddresses.iterator();
+ while(it.hasNext())
+ {
+ InetAddress broadcast = (InetAddress)it.next();
+ System.out.println("Sending broadcast datagram packet to " + broadcast);
+ DatagramPacket packet = new DatagramPacket(data, data.length, broadcast, 3000);
+ socket.send(packet);
+ // TODO experiment with these! 8)
+ packet = new DatagramPacket(fireArray, fireArray.length, broadcast, 3000); // alternate
+ socket.send(packet);
+ }
+
+ // Send every 1 sec. Otherwise this will be all over in a fraction of a second.
+ Thread.sleep(3000);
+ location = espdu.getEntityLocation();
+ System.out.println("Espdu #" + idx + " EID=[" + entityID.getSite() + "," + entityID.getApplication() + "," + entityID.getEntity() + "]");
+ System.out.println(" DIS coordinates location=[" + location.getX() + "," + location.getY() + "," + location.getZ() + "]");
+ System.out.println(" Orientation: " + orientation.getTheta());
+ //System.out.println(" Location (lat/lon/alt): [" + lat + ", " + lla[1] + ", " + lla[2] + "]");
+
+ }
+ }
+ catch(IOException | InterruptedException e)
+ {
+ System.out.println(e);
+ }
+
+}
+
+ /**
+ * A number of sites get all snippy about using 255.255.255.255 for a broadcast
+ * address; it trips their security software and they kick you off their
+ * network. (Comcast, NPS.) This determines the broadcast address for all
+ * connected interfaces, based on the IP and subnet mask. If you have
+ * a dual-homed host it will return a broadcast address for both. If you have
+ * some VMs running on your host this will pick up the addresses for those
+ * as well--eg running VMWare on your laptop with a local IP this will
+ * also pick up a 192.168 address assigned to the VM by the host OS.
+ *
+ * @return set of all broadcast addresses
+ */
+ public static Set<InetAddress> getBroadcastAddresses()
+ {
+ Set<InetAddress> broadcastAddresses = new HashSet<>();
+ Enumeration interfaces;
+
+ try
+ {
+ interfaces = NetworkInterface.getNetworkInterfaces();
+
+ while(interfaces.hasMoreElements())
+ {
+ NetworkInterface anInterface = (NetworkInterface)interfaces.nextElement();
+
+ if(anInterface.isUp())
+ {
+ Iterator it = anInterface.getInterfaceAddresses().iterator();
+ while(it.hasNext())
+ {
+ InterfaceAddress anAddress = (InterfaceAddress)it.next();
+ if((anAddress == null || anAddress.getAddress().isLinkLocalAddress()))
+ continue;
+
+ //System.out.println("Getting broadcast address for " + anAddress);
+ InetAddress broadcastAddress = anAddress.getBroadcast();
+ if(broadcastAddress != null)
+ broadcastAddresses.add(broadcastAddress);
+ }
+ }
+ }
+
+ }
+ catch(SocketException e)
+ {
+ e.printStackTrace();
+ System.out.println(e);
+ }
+
+ return broadcastAddresses;
+ }
+
+}
diff --git a/projects/Assignments/homework3/Sasala_README.md b/projects/Assignments/homework3/Sasala_README.md
new file mode 100644
index 0000000000000000000000000000000000000000..9e62214da8776261af2c6cbc52a43e50e31b8041
--- /dev/null
+++ b/projects/Assignments/homework3/Sasala_README.md
@@ -0,0 +1,29 @@
+## Homework Assignment 3 Checklist
+
+1. [x] Add X3D-Edit as Netbeans Plugin from https://savage.nps.edu/X3D-Edit/#Downloads
+
+2. [x] Optional: checkout Open-DIS-Java library source from https://github.com/open-dis/open-dis-java
+
+3. [x] Otherwise just inspect files of interest from
+ [edu.nps.moves.examples](https://github.com/open-dis/open-dis-java/tree/master/src/main/java/edu/nps/moves/examples)
+
+4. [x] Copy README.md and create YournameREADME.md documentation file...
+
+5. [x] Plan a track of interest - entity travels in a circle and changes heading(orientation) correspondingly
+
+6. [x] Copy, then Refactor/Rename example file OpenDisEspduSender.java or OpenDisPduSender.java as YourNameSomething.java
+
+7. [x] Modify your example file to produce track PDUs (and be cool)
+
+8. [x] Generate PDUs...
+
+9. [x] Test PDU reading using Wireshark...example below (see also screenshot file)
+
+835 46.316530 172.20.155.227 172.20.159.255 DIS 186 PDUType: 1 Entity State, Platform, Land, (1:1:2)
+799 43.208823 172.20.155.227 172.20.159.255 DIS 186 PDUType: 1 Entity State, Platform, Land, (1:1:2)
+722 40.094776 172.20.155.227 172.20.159.255 DIS 186 PDUType: 1 Entity State, Platform, Land, (1:1:2)
+631 37.026221 172.20.155.227 172.20.159.255 DIS 186 PDUType: 1 Entity State, Platform, Land, (1:1:2)
+
+10. [x] Record PDU file using X3D-Edit...
+
+11. [x] Playback PDU file using X3D-Edit...