You will be presented with the full text of a science research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
with the quickly development of nano technology , the scale of electrical devices becoming smaller and smaller , and the ability of single nano machine is very limited due to its size , therefore , sharing information among nano machines is good for the use of single nano machine through the connection of them , which organise the nano network . achieving the communication of nano machines has two main ways which are nano electrical communication through carbon nanotubes and molecular communication through information molecules . among them , molecular communication(mc ) is the most potential way to achieve , which relies on the bio - inspired method and fits for the biological environment .
+ at the open space of biological environment , the three dimensional space is fit for molecular communication@xcite to model channel . in mahfuz
et al s articles , they elaborated on the spatiotemporal distribution of information messages under the binary concentration - encoded modulate methods .
mahfuz s researches have a great impact on the study of molecular communication , which gives us a new modulate methods .
for the binary concentration - encoded modulate methods , it s much fit for the biological environment , and without considering the inner structures of the molecules .
also in akan s paper , he studied the ligand and receptor process of molecular communication , in order to study the details of how molecules bind with the receptors , which is based on the binary concentration - encoded modulate methods .
+ all of their works help us understand the molecular communication clearly .
as we know in molecular communication different modulation methods or different transportation environment can make different channel .
most studies are based on the three dimensional environmental , and fews are concentrate on the one dimensional environment .
comparing with the three dimensional , one dimensional can make sure the receiver receive all the information molecules for a long time , and the one dimensional situation is simple enough , therefore , it is worth for us to study it and it has a wealth of applications .
for instance , in nariman s molecular communication test - bed , which is studied based on the one dimensional environment . also in extremely tiny pipe , the transmitter and receiver nano machines on sides of the pipe can regard as in the same line . additionally ,
when transmitter and receiver nano machines are in extremely small distance , we can consider they are in one dimensional environment .
+ in this paper , we mainly considered in the tiny slim pipe , how the continuous information molecules are transmitted . and how the information transmission is affected by the transmission frequency and the distance of transmitter and receiver .
the study can help us know how the frequency affect the communication between nano machines . also can help us to place the nano machines in the future .
+ the paper is organised as follows : in section [ sec_mc_model ] , we produced a molecular comunication model ; in section [ sec_sample_threshold ] we introduced the sample method and the threshold of the receiver ; in section [ sec_analysis ] , we analyzed some parameters which affect the model ; in section [ sec_conclusion ] , we make a conclusion of our work .
we model a communication system composed of a pair of devices which are connected by an extremely slim pipe , each called a nanonetworking - enabled node(nen , ie .
, nano node or nano robot)@xcite .
the communication system is described as fig.[fig_mc_model ] . in molecular communication via diffusion(mcvd ) , the nens communicate with each other through the propagation of certain molecules via diffusion@xcite .
the tn transmits the encoded information molecules in the propagation medium , the communication phase being known as the sending phase .
the transmitted molecules propageated by the channel , the bind with the rn , which is known as the ligand - receptor binding@xcite .
since the tn and rn nano machine are connected by the extremely slim pipe , surely , we can consider the tn and rn in the one dimensional environment , then we can study its spatiotemporal distribution of signal strength in one dimensional environment .
the emission of information can be an instantaneous or a continuous emission .
as the instantaneous release of information molecules , in a single puff , would be ideal design for communications requiring rapid fade - out .
on the other hand , the source emitting message molecules continuously at a constant rate , to some extent might be useful for status telemetry , navigational beacons or periodic sampling monitors@xcite . in this paper
we regard the emission is continuous .
+ the spatiotemporal distribution of molecules transmitted by the tn that will be available at rn is calculated by the well - known roberts equation explained in @xcite .
we assume that a point source type tn continuously emitting molecules at a rate @xmath0 molecules per second , x is taken as the distance down the pipe from the source , @xmath1 is the cross - sectional area of the long and slim pipe , and the concentration of molecules @xmath2 at distance @xmath3 and time instant @xmath4 , then in one dimensional situation , @xmath2 is described as follows eq.[equation_spatiotemporal_1d ] , @xmath5 where @xmath6 as the dummy variable of integration , d is the diffusion constant in @xmath7 .
+ we use the on - off modulation method to transmit information . by transmit 1 bit , the tn will emitting a quantity of molecules @xmath8 , and transmit 0 bit , the tn will emitting nothing to the channel .
we utilize @xmath9 stands fot the emitting frequency of tn , and @xmath10 is the emitting period . in the emitting period , we can emitting molecules continuously , or transmitting nothing as described in eq.[equation_on_off ] or fig.[fig_on_off_modulation ] .
in this paper , we regard @xmath0 as a constant value @xmath12 which is the average molecules in the emitting period .
as aforementioned we transmit `` 1 '' when emitting a quantity of molecules , and transmit `` 0 '' when emitting nothing .
in this situation , the distance between tn and rn is x , as fig.[fig_single_duration_spray ] describes , we try to transmit bit sequences `` 10110 '' .
when molecules were transmitted to the receiver(rn ) , the rn needs to decide the information is `` 1 '' or `` 0 .
therefore , we need to set a threshold for the receiver , by comparing the available information molecules(aim ) to the threshold , we can know the information is ' ' 1 `` if the aim is great or equal than the threshold , and in vice versa , the information is ' ' 0 " . in the rn side , it s no need to sample the value of aim for each time instant , according to the nyquist 
shannon sampling theorem , we can get the sampling value at time instant of @xmath13 is @xmath14 , where @xmath15 is the length of the bit information , we only need to compare the @xmath14 to the threshold . in fig.[fig_single_duration_spray ] , the red arrow is the sampling instant , and the interference is the noise information molecules from the previous molecules informations , in this paper , for a simple description , we only need to consider one bit information of the previous information molecules .
in this section , we study how the distance and emitting frequency affect the transmission under the environment of air medium . and at last
, we do the simulation to testify the difference of information transmission in one dimensional(1-d ) situation and three dimensional(3-d ) situation . in this section ,
we only transmit two bit information `` 10 '' , for it can help us analysis the aim in the first bit `` 1 '' , and interference in the second bit `` 0 '' .
we assume that the @xmath12 is 10000 molecules / sec , @xmath16 is 30@xmath17 , the diffusion coefficient in air medium is @xmath18=0.43@xmath19 , we utilize the model in eq.[equation_spatiotemporal_1d ] to do the simulation at different distances , such as @xmath3 are 0.05@xmath20,1@xmath20,10@xmath20 respectively .    through the fig.[fig_distance_varies ] , we find that with the increase of distance between tn an rn , the aim in the rn side is become smaller and smaller , but the interference is becoming larger and larger .
therefore , we need to set the distance at short distance , in order to transmit enough information molecules , and improve the probability of successful information transmission .      assuming that the @xmath12 is 10000 molecules / sec ,
the distance between tn and rn is @xmath21 , and the diffusion coefficient in air medium is @xmath22 . using the model in eq.[equation_spatiotemporal_1d ]
, we do the simulation at different emitting frequencies , such as @xmath23,@xmath24 and @xmath25 .    through the fig.[fig_distance_varies ]
, we find that with the increase of @xmath9 , the aim in the rn side is become smaller and smaller , also the interference is becoming smaller and smaller .
since the aim and interference increase or decrease simultaneously , we need to make a compromise for the change of frequency , in order to transmit enough information molecules , and improve the probability of successful information transmission
.      we need to do some researches to study the differences between one dimensional situation and three dimensional situation .
we use the same basic values of the parameters described before , except for the distance @xmath26 , the frequency @xmath27 .
the three dimensional model of molecules transmission is adapted from @xcite .
the simulation result shows in fig.[fig_compare_1d_3d ] .    from fig.[fig_compare_1d_3d ] , we know that the 3-d line higher than 1-d , and the interference is almost the same .
in one dimensional situation can make sure the receiver the information molecules completely in certain time , however , the available information in three dimensional situation is higher .
we think the reason is that in three dimensional situation , there are a large quantities of molecules in certain time slot , but to the one dimensional situation the information molecules needs to transmit sequencely which result the through out is smaller .
in this paper , we studied continuous molecules were transmitted in one dimensional molecular communication .
we use binary concentration - encoded method to encode information molecules into bit `` 1 '' or `` 0 '' , also we introduce sample theorem and threshold for the receiver to decode information molecules .
to study the molecular communication deeper , we studied that how the metrics of distance and frequency affect the molecules concentration , and we learned that the longer the distance the lower of the available information molecules in rn , but higher in interferences , and the frequency has two sides on the available molecular communication , either positive or negative , therefore , we should make a compromise between the available information molecules and the interferences from the former information bits .
finally , we made a comparison between one dimensional situation and three dimensional situation , and we find that in three dimensional situation , the rn side has a higher available information molecules , but can not make sure the rn receives the molecular information for one hundred percent .
+ still there are many areas need to study , for the future research work , we can promote our research from three aspects .
for the first , we can study how the variation of different emit rates affect the molecules concentration .
for the second , we should find a method to make a cut - off between the frequency and the interference , in order to make the communication more accurate and high efficiency . for the third
, we should consider to combine the advantages of the three dimensional and one dimensional situation to improve the available information molecules .
this work was supported by the national natural science foundation of china ( 61173190 ) and the fundamental research funds for the central universities(gk201501008 ) .
h.  b. yilmaz , a.  c. heren , t.  tugcu , and c .- b .
chae , `` three - dimensional channel characteristics for molecular communications with an absorbing receiver , '' _ communications letters , ieee _ , vol .  18 , no .  6 , pp .
929932 , 2014 .
m.  u. mahfuz , d.  makrakis , and h.  t. mouftah , `` on the characterization of binary concentration - encoded molecular communication in nanonetworks , '' _ nano communication networks _ , vol .  1 , no .  4 , pp . 289300 , 2010 .          m.  mahfuz , d.  makrakis , and h.  mouftah , `` a comprehensive analysis of strength - based optimum signal detection in concentration - encoded molecular communication with spike transmission , '' _ nanobioscience , ieee transactions on _ , vol .  14 , no .  1 ,
6783 , jan 2015 .
molecular communication as the most potential methods to solve the communication in nano scale , for it s derived from nature , and it becomes more and more prevalent . 
 though molecular communication happens in three dimensional situation , there are also some situation that are in the one dimensional situation , especially when considering the transmitters and the receivers are in extremely short distance or in long slim pipe . in this paper , we introduce the one dimensional situation , and studied how the continuous information molecules transmitted in this situation , also introduced how to encode and decode the information molecules , and based on the molecular communication model , we studied some metrics of it , such as the distance between transmitter and receiver , the emitting frequency of transmitter . through the research we know that the distance and frequency are important metrics to the successful communication , which can direct us how to place the nano transmitters and receivers in the future nano network environment .