On Fri, Jul 24, 2009 at 7:48 AM, Rémi Villé<[email protected]> wrote: > Hi, > > I try to aggregate values sent by mote using CTP. > > In the example MultihopOscilloscope, the aggregation is made by sending 5 > readings in one message every 1024 ms. I would like to aggregate values > using their similarity, ie saying in a message that, for example, mote 5, 6 > and 7 have sensed the same value 1500 whereas saying that mote 5 sensed > 1500, mote 6 sensed 1500 and mote 7 sensed 1500. > > So my message will look like this : > > typedef nx_struct { > uint16_t logic_date_send; // Lamport send date > uint8_t agg_buf_size; // size off agg_buf > uint8_t agg_buf[AGG_BUF_MAX_SIZE]; // > ((<logic_date><mote_id>)+<nb_id><val>)* > } agg_msg_t; > > agg_buf contains the real message expressed like this (using regular > expression) : > (<value><nb_id>(<mote_id><logic_date>)+)* > 2 byte 1 byte 1 byte 2 byte > > With this sort of message, knowing that "call Send.maxPayloadLength()" (on > telosb) returns 20 byte, I can only have 2 different values in one message. > In the best case I can send 5 values for 5 mote which have sensed the same > value (I don't obtain better result compared with default > MultihopOscilloscope example, except for causal date precision). > > if I express the message like this : > (<value><nb_id>(<mote_id><logic_date_1,logic_date_2>)+)* > where : logic_date_2 is the Lamport date since logic_date_1 where mote_id > sensed the same data, > I can maybe obtain better results. > > So I really don't know what is the good way to aggregate data in a message > using similarity, maybe should I send several messages, each one containing > one value and a list of <mote_id, logic_date>. > I would like to know if someone have experience in programming aggregation > based on similarity, and which solution would be the best, or maybe some > publications on the subject.
CAG by SunHee Yoon is one example: http://www-scf.usc.edu/~sunheeyo/CAG-TOSN-sunheeyoon.pdf If you want larger payload, you can change TOSH_DATA_LENGTH. - om_p _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
