CN105228160A - A kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network - Google Patents

Abstract

The invention discloses a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network, utilize part mobility node repair part cavity, make guarded region form a strong fence and cover, realize the defense function of guarded region.This method for repairing and mending utilizes graph theory thought, and the fence finding empty number minimum in across whole guarded region repairs object as cavity, thus reduces movable joint and count; Secondly, utilize cavity and mating between mobile node, find the cavity-mobile node matching scheme making mobile node displacement the shortest, and then the energy that reduction mobile node consumes in moving process, extend network lifetime.

Description

A kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network

Technical field

The present invention relates to wireless sensor network technology field, more specifically relate to a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network.

Background technology

Wireless sensor network (WirelessSensorNetwork, WSN) be current that receive much concern in the world, contain one of integrated hot research field, forward position of multi-crossed disciplines, knowledge height.It combines embedded computer technology, sensor technology, wireless communication technology, distributed information processing and wireless communication technology etc., by multiple integrated sensor capability cooperation, gather the various environment of perception or monitoring target information, MANET is formed by the mode of multi-hop, finally wirelessly these data are sent to user terminal, thus realize the Real-Time Monitoring to environmental information.WSN has very wide application prospect, potential practical value is had at military and national defense, industrial or agricultural, city management, biologic medical, environmental monitoring, rescue and relief work, the anti-probably numerous areas such as anti-terrorism, deathtrap Long-distance Control, and having obtained the extensive concern of countries in the world military service, academia and industrial quarters, many universities both domestic and external and research institution have all dropped into a large amount of research and development strengths and have been engaged in this work.

The initial stage is set up at a wireless sensor network, network coverage problem is the problem considered at first, namely under the prerequisite of (QoS) that guarantees service quality, how making rational planning in guarded region or area-of-interest (FieldofInterest:FOI) and dispose the problem of each sensor node, is also the hot issue of current wireless sensor network research.Object according to covering can be divided into following three kinds of coverings usually: target coverage (targetcoverage), and fence covers (barriercoverage) and region overlay (areacoverage) three kinds.It is the probability problem that moving object is passed through Sensor monitoring region and is found or is detected that fence covers the target investigated, military and, the field such as national defense safety and fire hazard monitoring all has a wide range of applications.

It is one of study hotspot of wireless sensor network that fence covers, and has achieved certain achievement in research, but existing work is mainly based on the static sensor net that the sensor node without mobility forms.Utilize the static sensor network of random placement to implement fence to guarded region to cover, there are following three problems: (1) randomness owing to disposing, may exist in sensor network and cover cavity, can not ensure to form reliable fence in guarded region, thus be difficult to ensure very to monitor the moving target passing through guarded region; (2) for avoiding the existence covering cavity, guarantee that forming reliable fence covers, most of research work is all passed through to improve node deployment density, dispenses great deal of nodes, thus causes node redundancy, bring cost to waste; (3) after sensor network work a period of time, part of nodes causes energy ezpenditure totally due to a variety of causes, cannot monitor work normally, therefore leaves Energy volution problem at guarded region, cannot implement the monitoring of reliable fence.

If operative sensor node possesses mobility, after network design completes, the locomotivity of part of nodes can be utilized heavily to dispose, final formation 1 or the continual transducer fence traversing guarded region of K bar, realize 1 or the covering of K-fence, simultaneously relative to pure static sensor net, the sensor node quantity during mixing Sensor Network fence covers is greatly reduced.To consume a large amount of energy because sensor node moves, and node gross energy is limited, therefore for the heavy deployment issue of removable node, formulates and optimizes rational mobile route, reducing node motion distance is the problem needing emphasis to consider.Because mobile node cost is relatively high, a large amount of removable nodes in guarded region, can not be used, utilize a large amount of static nodes and a small amount of mobile node to form hybrid wireless sensor network and compare that the former is more suitable.This mixing Sensor Network can utilize the mobility of mobile node to guarantee to form fence, can reduce again the sensor node number needed for fence, reduces fence and forms cost, improve the life span of whole Sensor Network.Therefore, based on the node deployment strategy study necessarily trend of the times that the wireless sensor network fence of part mobility node covers.

Summary of the invention

(1) technical problem that will solve

The present invention mainly utilizes the mobility of operative sensor node, repair in network and cover cavity, in Sensor Network, realize fence cover, the technical problem mainly solved is to reduce movable joint in mixing Sensor Network and counts, reduce the energy that mobile node consumes in moving process, extend network lifetime, therefore a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network is provided.

(2) technical scheme

In order to solve the problems of the technologies described above, the invention provides a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network, described method is included in mixing Sensor Network and searches minimum empty number fence:

The dummy node φ that two represent zone boundary is introduced in monitored area ₀and φ ₁, suppose φ ₀represent the leftmost side, monitored area, i.e. (x=0), φ ₁represent the rightmost side of monitored area, i.e. (x=L); Construct a directed graph G (V, E), in directed graph G, V includes all sensor nodes; Line e between every two nodes _ijthere is a weights omega (e _ij), this weighted value represents node v _iwith node v _jbetween empty number, the concrete make of limit collection E is as follows:

For all the sensors node, do not comprise two dummy nodes representing border, weights ω (e _ij) can be expressed as follows:

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}(v_i,v_j-2R_s)}{2R_s}\right]+1,\mathrm{dist}(v_i,v_j)>2R_s\\ 0,\mathrm{otherwise}\end{array}\right.$

Wherein, dist (v _i, v _j) represent node v _iwith v _jdistance, have when ω (e)=0, namely do not cover cavity between this two node;

By two dummy node φ ₀and φ ₁join in bipartite graph G (V, E) above, construct a new bipartite graph, wherein V'=V ∪ φ ₀∪ φ ₁; For v _i∈ V, 1≤i≤N, has

$\left\{\begin{array}{c}\mathrm{dist}({\mathrm{\φ}}_0,v_i)=x_i\\ \mathrm{dist}({\mathrm{\φ}}_1,v_i)=L-x_i\end{array}\right.$

For dummy node weights omega (e _ij) can be expressed as follows:

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}({\mathrm{\φ}}_j,v_i)-R_s}{2R_s}\right],\mathrm{dist}({\mathrm{\φ}}_j,v_i)>R_s\\ 0,\mathrm{otherwise}\end{array}\right.$

Determine the empty number existed between any two nodes according to above formula, namely complete bipartite graph G'(V', E') initialization procedure; What represent due to the weights on any two node lines is two internodal empty numbers, so finds minimum empty number fence and is converted into and finds the leftmost side, monitored area φ ₀to rightmost side φ ₁between shortest path, the shortest i.e. weights said here are minimum, and therefore we search minimum empty number fence by what ask shortest path thinking to be incorporated into this programme in graph theory, and the shortest path that in graph theory, shortest path first obtains is found minimum empty number fence.

Further, described method also comprises and to determine in mixing Sensor Network cavity position in fence:

For any two the adjacent sensor nodes on minimum empty number fence, because the empty number between them is ω (e), to a kth empty h _k(x, y), its positional representation is as follows:

h _k(x,y)＝(x _i+k×Δx,y _i+k×Δy)k∈[1,w(e)]，

$\left\{\begin{array}{c}\mathrm{\Δx}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\sin \mathrm{\θ}\\ \mathrm{\Δy}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\cos \mathrm{\θ}\end{array}\right.$

Wherein determine according to above two formulas and need repair cavity positions all in fence.

Further, described method also comprises finds cavity and the Optimum Matching of mobile node, reduce all mobile nodes displacement and:

Utilize the mobility of node, movable part sensor node goes to repair the cavity in fence, therefore the problem regulating mobile node to go to repair some or multiple empty problem to be equal to Optimum Matching between cavity and mobile node, namely Optimum Matching requires to find and makes all mobile node displacement minimum, supposes that all mobile nodes are expressed as

X＝{x ₁,...,x _M}

Cover cavity in fence to be expressed as

Y＝{y ₁,...,y _H}

For by all mobility nodes with cover the bipartite graph G (V, E) that forms of cavity, V=X ∪ Y and wherein limit collection E={e _ij, i ∈ X, j ∈ Y}, for each limit e _ijrepresent mobile node x _iwith the empty y of covering _jline have weights, for representing that mobile node moves to cavity position and carries out cavity and repair the distance of movement.

(3) beneficial effect

The present invention is based on the ABC of graph theory, consider in overlay area to there are many possibility fence, thus propose to look for minimum empty number fence and the method for being repaired it by the removable node of use.Based on the fence method for repairing and mending of minimum empty number fence in the present invention's mixing Sensor Network, by the coupling in cavity in the fence of removable node and minimum empty number, compared with traditional empty method for repairing and mending, not only achieve the repairing completing fence cavity with minimum mobile node, make to form a strong fence in monitored area, meanwhile also assures that the average moving distance of mobile node is minimum, thus decrease the consumption of mobile node energy in empty mending course.

Accompanying drawing explanation

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, be briefly described to the accompanying drawing used required in embodiment or description of the prior art below.Apparently, the accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

Fig. 1 is that mixing Sensor Network fence covers schematic diagram;

Fig. 2 is that mixing Sensor Network fence covers schematic diagram;

Fig. 3 is that mixing Sensor Network fence covers schematic diagram;

Fig. 4 is empty position view in minimum empty number fence.

Embodiment

Below in conjunction with drawings and Examples, embodiments of the present invention are described in further detail.Following examples for illustration of the present invention, but can not be used for limiting the scope of the invention.

The mixing Sensor Network model that the present invention uses

Consider that the cost of mobile node is higher, present invention employs the hybrid sensor network be made up of static node and mobile node.Suppose that all the sensors node all follows 0/1 sensor model, namely the sensing region of each transducer take node as the circle in the center of circle, and when in the perception radius that intrusion target is in node, then the probability that this target is perceived is 1; And when the perception radius that intrusion target is in node is outer, then the probability be perceived is 0, as shown in Figure 1.Sensor node round dot represents, white represents removable node, and grey represents static node, the area of circle and the sensor coverage region of node.The guarded region covered for fence generally all adopts rectangular area as shown in the figure, and all the sensors node all dispenses along a predetermined straight line, straight line as long in the black in Fig. 1.

Because mobile node cost is relatively high, in guarded region, all mobile node can not be used.A large amount of static nodes and a small amount of mobile node is utilized to form hybrid wireless sensor network more suitable, the mobility of mobile node can be utilized to guarantee to form fence, the sensor node number needed for fence can be reduced again, reduce fence and form cost, improve the life span of whole Sensor Network.To consume a large amount of energy because sensor node moves, and node gross energy is limited, therefore formulates the mobile route optimized when rational removable node is heavily disposed, reducing node motion distance is the problem that emphasis is considered.And when forming fence protection, how to reduce and to form sensor node needed for fence, reduce fence cost, the utilance improving sensor node is the emphasis should considered in empty method for repairing and mending equally.

As shown in Figure 2, from static node v _kto v _k+3there are 5 possible fence paths, i.e. v _k→ v _k+3; v _k→ v _k+1→ v _k+3; v _k→ v _k+2→ v _k+3; v _k→ v _k+1→ v _k+2→ v _k+3and v _k→ v _k+2→ v _k+1→ v _k+3.Therefore from the leftmost side of guarded region to the rightmost side, there are many possibility fence equally, and in each possibility fence, there is the cavity that number differs.Therefore, first the cavity repairing problem covered for fence should find a minimum empty number fence, and next is only considers to utilize the mobility of node to go to repair cavity.The distance of the energy and its movement that move consumption due to mobile node is directly proportional, and therefore should consider how to reduce the distance between mobile node to cavity in mending course.This problem can be equivalent to the Optimum Matching problem in mobile node and this fence between cavity, mobile node works according to carrying out repairing cavity in Optimum Matching result with the target cavity of its pairing, guarantees to form the displacement reducing mobile node while fence covers.Therefore our target function can be expressed as:

$\underset{h=1}{\overset{\mathrm{num}}{\mathrm{\Σ}}}{d}_{\mathrm{mh}}{x}_{\mathrm{mh}}---\left(1\right)$

Wherein h (x _h, y _h) represent cavity position, d _mhrepresent the distance of mobile node m to empty h.X _mhcan be expressed as follows:

In sum, mobility node is utilized to repair fence cavity in mixing Sensor Network, reduce mobile node number and displacement thereof while the fence covering of forming region, thus raising Duty-circle, reduction energy ezpenditure are the problems that mobile node needs in the present invention to consider.

For the problem of above-mentioned proposition, utilize in graph theory and ask shortest-path method, the invention provides a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network, the method is as follows:

Search minimum empty number fence: first in monitored area, introduce the dummy node φ that two represent zone boundary ₀and φ ₁, suppose φ ₀represent the leftmost side, monitored area, i.e. (x=0), φ ₁represent the rightmost side of monitored area, i.e. (x=L).Construct a directed graph G (V, E), in directed graph G, V includes all sensor nodes.Line e between every two nodes _ijthere is a weights omega (e _ij), this weighted value represents node v _iwith node v _jbetween empty number, the concrete make of limit collection E is as follows:

For all the sensors node, do not comprise two dummy nodes representing border, its weights can be expressed as

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}(v_i,v_j-2R_s)}{2R_s}\right]+1,\mathrm{dist}(v_i,v_j)>2R_s\\ 0,\mathrm{otherwise}\end{array}\right.---\left(3\right)$

Wherein, dist (v _i, v _j) represent node v _iand v _jdistance, have when ω (e)=0, represent and do not cover cavity between this two node.

By two dummy node φ ₀and φ ₁join in bipartite graph G (V, E) above, construct new bipartite graph G'(V', an E'), wherein V'=V ∪ φ ₀∪ φ ₁.For v _i∈ V, 1≤i≤N, has

$\left\{\begin{array}{c}\mathrm{dist}({\mathrm{\φ}}_0,v_i)=x_i\\ \mathrm{dist}({\mathrm{\φ}}_1,v_i)=L-x_i\end{array}\right.---\left(4\right)$

For comprising dummy node

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}({\mathrm{\φ}}_j,v_i)-R_s}{2R_s}\right],\mathrm{dist}({\mathrm{\φ}}_j,v_i)>R_s\\ 0,\mathrm{otherwise}\end{array}\right.---\left(5\right)$

Determine the empty number existed between any two nodes according to above formula, i.e. bipartite graph G'(V', E') initialization complete.Due to the weights representative on any two node lines is empty number between two nodes, so finds minimum empty number fence and can be converted into the searching leftmost side, monitored area φ ₀to rightmost side φ ₁between shortest path, the shortest i.e. weights said here are minimum.Therefore we quote in graph theory and ask shortest path thinking to find minimum empty number fence.Minimum empty number fence required in the shortest path obtained according to shortest path first and the present invention, the black dotted lines in Fig. 2.

Determine cavity position in fence

For any two the adjacent sensor nodes on minimum empty number fence, because the empty number between them is ω (e).To a kth empty h _k(x, y), know that its position can by representing as follows by Fig. 4:

h _k(x,y)＝(x _i+k×Δx,y _i+k×Δy)k∈[1,w(e)](6)

$\left\{\begin{array}{c}\mathrm{\Δx}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\sin \mathrm{\θ}\\ \mathrm{\Δy}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\cos \mathrm{\θ}\end{array}\right.---\left(7\right)$

Wherein can determine according to above two formulas and need repair cavity positions all in fence, as shown in Figure 3, the little triangle of the black in figure represents empty position.

Find cavity and the perfect matching of mobile node, reduce the displacement summation of mobile node

Be the mobility utilizing node due to what adopt in this programme, movable part sensor node goes to repair the cavity in fence, the problem therefore regulating mobile node to go to repair some cavities or multiple empty problem to be equal to Optimum Matching between cavity and mobile node.Namely requiring to find for the Optimum Matching in this programme makes all mobile node displacement minimum.Suppose that all mobile nodes can be expressed as

X＝{x ₁,...,x _M}(8)

Cover cavity in fence can be expressed as

Y＝{y ₁,...,y _H}(9)

For all mobility nodes with cover the bipartite graph G (V, E) that forms of cavity, V=X ∪ Y and wherein limit collection E={e _ij, i ∈ X, j ∈ Y}, for each limit e _ij(represent mobile node x _iwith the empty y of covering _jline) have weights for representing that mobile node moves to cavity position and carries out cavity and repair the distance of movement.

During mixing Sensor Network fence is covered in empty method for repairing and mending; find out the minimum empty number fence across both sides, overlay area; empty matching mechanisms in removable node reasonable in design and this fence; mobile node repairs the cavity in fence; the strong fence realizing monitored area covers, and the available protecting preventing foreign invaders from realizing monitored area to its invasion and destruction is urgently to be resolved hurrily.The present invention is based on the ABC of graph theory, consider in overlay area to there are many possibility fence, thus propose to look for minimum empty number fence and the strategy repaired it by the removable node of use.The present invention is by the coupling in cavity in several fence in removable node and minimum cavity, provide a kind of fence method for repairing and mending mixed based on minimum empty number fence in Sensor Network, compared with traditional empty method for repairing and mending, not only achieve the repairing completing fence cavity with minimum mobile node, make to form a strong fence in monitored area, meanwhile also assures that the average moving distance of mobile node is minimum, thus decrease the consumption of mobile node energy in empty mending course.

Above execution mode is only for illustration of the present invention, but not limitation of the present invention.Although with reference to embodiment to invention has been detailed description, those of ordinary skill in the art is to be understood that, various combination, amendment or equivalent replacement are carried out to technical scheme of the present invention, do not depart from the spirit and scope of technical solution of the present invention, all should be encompassed in the middle of right of the present invention.

Claims (3)

1. mix the fence method for repairing and mending based on minimum empty number fence in Sensor Network, it is characterized in that, the method is included in mixing Sensor Network and searches minimum empty number fence:

The dummy node φ that two represent zone boundary is introduced in monitored area ₀and φ ₁, suppose φ ₀represent the leftmost side, monitored area, i.e. (x=0), φ ₁represent the rightmost side of monitored area, i.e. (x=L); Construct a directed graph G (V, E), in directed graph G, V includes all sensor nodes; Line e between every two nodes _ijthere is a weights omega (e _ij), this weighted value represents node v _iwith node v _jbetween empty number, the concrete make of limit collection E is as follows:

For all the sensors node, do not comprise two dummy nodes representing border, weights ω (e _ij) can be expressed as follows:

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}(v_i,v_j-2R_s)}{2R_s}\right]+1,\mathrm{dist}(v_i,v_j)>2R_s\\ 0,\mathrm{otherwise}\end{array}\right.$

Wherein, dist (v _i, v _j) represent node v _iwith v _jdistance, have when ω (e)=0, namely do not cover cavity between this two node;

By two dummy node φ ₀and φ ₁join in bipartite graph G (V, E) above, construct a new bipartite graph, wherein V'=V ∪ φ ₀∪ φ ₁; For v _i∈ V, 1≤i≤N, has

$\left\{\begin{array}{c}\mathrm{dist}({\mathrm{\φ}}_0,v_i)=x_i\\ \mathrm{dist}({\mathrm{\φ}}_1,v_i)=L-x_i\end{array}\right.$

For dummy node weights omega (e _ij) can be expressed as follows:

$\mathrm{\ω}\left(e_{\mathrm{ij}}\right)=\left\{\begin{array}{c}\left[\frac{\mathrm{dist}({\mathrm{\φ}}_j,v_i)-R_s}{2R_s}\right],\mathrm{dist}({\mathrm{\φ}}_j,v_i)>R_s\\ 0,\mathrm{otherwise}\end{array}\right.$

Determine the empty number existed between any two nodes according to above formula, namely complete bipartite graph G'(V', E') initialization procedure; What represent due to the weights on any two node lines is two internodal empty numbers, so finds minimum empty number fence and is converted into and finds the leftmost side, monitored area φ ₀to rightmost side φ ₁between shortest path, the shortest i.e. weights said here are minimum, and therefore we introduce asking shortest path in graph theory, search minimum empty number fence, and the shortest path that in graph theory, shortest path first obtains is found minimum empty number fence.

2. in mixing Sensor Network according to claim 1 based on the fence method for repairing and mending of minimum empty number fence, it is characterized in that, described method also comprises to determine in mixing Sensor Network cavity position in fence:

For any two the adjacent sensor nodes on minimum empty number fence, because the empty number between them is ω (e), to a kth empty h _k(x, y), its positional representation is as follows:

h _k(x,y)＝(x _i+k×Δx,y _i+k×Δy)k∈[1,w(e)]，

$\left\{\begin{array}{c}\mathrm{\Δx}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\sin \mathrm{\θ}\\ \mathrm{\Δy}=\frac{\mathrm{dist}(v_i,v_j)}{\mathrm{\ω}\left(e\right)+1}\cos \mathrm{\θ}\end{array}\right.$

Wherein determine according to above two formulas and need repair cavity positions all in fence.

3. in mixing Sensor Network according to claim 1 based on the fence method for repairing and mending of minimum empty number fence, it is characterized in that, described method also comprises finds cavity and the Optimum Matching of mobile node, reduce all mobile nodes displacement and:

Utilize the mobility of node, movable part sensor node goes to repair the cavity in fence, therefore the problem regulating mobile node to go to repair some or multiple empty problem to be equal to Optimum Matching between cavity and mobile node, namely Optimum Matching requires to find and makes all mobile node displacement minimum, supposes that all mobile nodes are expressed as

X＝{x ₁,...,x _M}

Cover cavity in fence to be expressed as

Y＝{y ₁,...,y _H}

For by all mobility nodes with cover the bipartite graph G (V, E) that forms of cavity, V=X ∪ Y and , wherein limit collection E={e _ij, i ∈ X, j ∈ Y}, for each limit e _ijrepresent mobile node x _iwith the empty y of covering _jline have weights, for representing that mobile node moves to cavity position and carries out cavity and repair the distance of movement.