Computing the maximum value using tiny aggregation (TAG)
The algorithm starts by getting motes without children to send their sensed value to the parents. When a mote receives a message it stores the largest value between the message and the motes own value. When a mote has received messages from all its children, it will send the maximum value to its parent unless it is the parent mote; in this case it will shout the maximum value.
See Protocol 4.10
Code designed by Matt Duckham. Additional coding by Alan Both.
Copyright 2011, 2012 Matt Duckham
This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License http://www.gnu.org/licenses/ for more details.
The formal specification procedure used for all the protocols on this site is based on the standard distributed systems approach of Nicola Santoro (see Santoro, N. Design and Analysis of Distributed Algorithms. Wiley, Hoboken, NJ. 2007.) For more details on the protocol specification style, please refer to the book accompanying book for this website, Decentralized Spatial Computing: Foundations of Geosensor Networks.
;; Copyright 2011, 2012 Matt Duckham ;; ;; This program is free software: you can redistribute it and/or modify ;; it under the terms of the GNU General Public License as published by ;; the Free Software Foundation, either version 3 of the License, or ;; (at your option) any later version. ;; ;; This program is distributed in the hope that it will be useful, ;; but WITHOUT ANY WARRANTY; without even the implied warranty of ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the ;; GNU General Public License for more details. ;; ;; You should have received a copy of the GNU General Public License ;; along with this program. If not, see <http://www.gnu.org/licenses/>. __includes["../gsn.nls"] ;; Define a new breed of turtle called motes breed [motes mote] ;; Each mote can store the local variables m which stores maximum value and r which ;; stores a tally of the messages received motes-own [m r] ;;Network Setup to initialize ;; Create a network with the restriction that it is a rooted tree if NetworkStructure = "Tree (UDG)" [create-udg create-tree] ;; UDG network if NetworkStructure = "Tree (GG)" [create-udg create-gg create-tree] ;; GG network if NetworkStructure = "Tree (RNG)" [create-udg create-rng create-tree] ;; RNG Network ask motes [ set m random 1001 ;; The sensed value is a random number between 0 and 1000 become "IDLE" ;; Set all motes to state IDLE set label m ] ask motes with [parent = ""] [ ;; Motes with no parent are not part of the tree ;; so will not be used become "DEAD" set label "" ;; The DEAD state does not have a label ] end ;; Runs the TAG algorithm to go ask motes [ step ] mote_labels ;; Changes the labels of the motes based on the MoteLabel dropdown list tick end ;; ;; Mote protocols ;; ;; Step through the current state to step if state = "IDLE" [ step_IDLE stop ] if state = "LSTN" [ step_LSTN stop ] end ;; Every mote transitions to the LSTN state. Motes without children send their m ;; value to their parent. to step_IDLE if length children = 0 [ ;; If mote has no children send list "MTAG" m (mote parent) ;; Send message to parent ] become "LSTN" end ;; When the mote receives a message, it selects the maximum value from its own sensed ;; value and the messages value. Once the mote has received a message from all its ;; children, it sends that value to its parent unless it is the root mote. In this ;; case it shouts the maximum value. to step_LSTN if has-message "MTAG" [ ;; Receiving MTAG let msg received "MTAG" set r (r + 1) set m max list m item 1 msg ;; Store the maximum value if length children = r [ ;; If messages from all children have been received ifelse parent = -1 [ ;; If mote is the parent mote show word "Maximum value in network is " m ] [ send list "MTAG" m (mote parent) ;; Send message to parent ] ] stop ] end ;; Changing the labels of the motes based on the MoteLabel dropdown list to mote_labels ask motes with [state != "DEAD"] [ ;; Motes in the DEAD state are ignored if MoteLabel = "none" [set label ""] ;; Hide the label if MoteLabel = "max value" [set label m] ;; Show maximum value if MoteLabel = "mote id" [set label who] ;; Show mote id if MoteLabel = "parent id" [set label parent] ;; Show parent id if MoteLabel = "children" [set label children] ;; Show list of children ] end
The NetLogo procedures for this applet can be downloaded directly as: Protocol4.10.nlogo
All the NetLogo simulation models for this book depend on two library files: gsn.nls and env.nls
These files should be placed in the parent directory of the .nlogo file (and are common to all the .nlogo models on this website).