THE SENSOR NETWORK

CROSS-REFERENCE TO RELATED APPLICATIONS)

This application claims the benefit under 35 U.S.C. § 119(a) of a Korean patent application filed in the Korean Intellectual Property Office on January 29, 2016, and assigned Serial No. 10-2016-0011969, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a sensor network and a method for fabricating the same, and more particularly, to a sensor network using an optical fiber and a method for fabricating the same.

BACKGROUND

In a conventional security method and system, a security fence is constructed by establishing an optical cable sensor network around a specific facility or area such as a military camp, a power plant, an airport, or a prison to protect the facility or area, and an intruder is detected by sensing a change in an optical signal transmitted along an optical cable. If the optical cable is damaged, for example, cut or bent due to intrusion inside the security fence or escape through the security fence, a light flow along the optical cable is distributed, a loss change of the optical signal is sensed, and thus intrusion or escape is sensed in this security system.

Conventionally, a network is established using a plurality of optical cables, or an optical cable network is established in a predetermined pattern by arranging optical cables at every predetermined interval and fixing them in a contact-free manner by means of clips or the like or by twisting the optical cables without using fixing clips.

However, the conventional method causes optical loss in view of fusion-contact between a plurality of optical cables in establishing a network with the plurality of optical cables, needs a complex fabrication process due to twisting and bending of optical cables in establishing a twisted network, increases the fabrication cost of an optical network in establishing a non-twisted, contact- free type network because complex clips are used, and has low safety against intrusion because clips are still easily removed during intrusion. The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure. SUMMARY

An aspect of the present disclosure is to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present disclosure is to provide a sensor network fixed by grid- fixing structures capable of fixing an optical cable in a parallel contact manner.

Another aspect of the present disclosure is to provide a method for establishing a network using a single line network formation scheme, which facilitates simultaneous network formation in a plurality of rows by means of the fixing structures and thus shortens a fabrication time significantly.

Another aspect of the present disclosure is to provide a security system with an improved sensor sensitivity through use of the sensor network.

In accordance with an aspect of the present disclosure, there is provided a sensor network. The sensor network includes an optical cable, and a plurality of fixing structures configured to fix the optical cable, for grid formation. A first part and a second part of the optical cable are arranged in parallel, contacting each other in each of the fixing structures.

Each of the fixing structures may include a first member and a second member engaged face to face, and each of the first and second members may include a linear optical cable container for forming a path along which the optical cable passes during assembly. At least one protrusion may be formed in the optical cable container to prevent slip-off of the optical cable.

The fixing structure may further include a through hole formed on an assembly surface of one of the first and second members, and a protrusion formed on an assembly surface of the other of the first and second members. The first member may be engaged with the second member by inserting the protrusion into the through hole.

The first member may be engaged with the second member by welding welding protrusions formed on assembly surfaces of the first and second members of the fixing structure. The welding may be performed by an ultrasonic welder. In accordance with an aspect of the present disclosure, there is provided a method for establishing a sensor network in which one optical cable is arranged simultaneously in a plurality of rows, using fixing structures, each including a first member and a second member and each of the first and second members including an optical cable container. The method includes arranging the first members of the fixing structures, forming a grid-type network by twice passing the optical cable in the optical cable container of each of the arranged first members, bringing the optical cables into contact in parallel in the optical cable container, arranging the second members of the fixing structures on the optical cable, and engaging the second members with the first members by pressing the second members with a pressing member.

The method may further include arranging a plurality of fixing jigs each having a plurality of grooves to accommodate the plurality of fixing structures in a horizontal direction, apart from each other, before the arrangement of the first members. The first members may be arranged in the grooves of the fixing jigs.

The method may further include welding welding protrusions formed on assembly surfaces of the engaged first and second members. The welding may be performed by an ultrasonic welder.

In accordance with an aspect of the present disclosure, there is provided a security system. The security system includes the above sensor network of the present disclosure, an optical transmission module connected to one end of the sensor network an optical reception module connected to the other end of the sensor network, for receiving an optical signal transmitted by the optical transmission module through the sensor network, a controller connected to the optical transmission module and the optical reception module, for controlling the optical transmission module and the optical reception module and determining an optical fiber state by receiving a signal from the optical reception module, and a display for displaying an intrusion situation by receiving a warning signal from the controller.

Other aspects, advantages, and salient features of the disclosure will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of certain exemplary embodiments of the present disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1A illustrates a grid-type sensor network woven with a single optical cable by means of grid-fixing structures according to the present disclosure;

FIG. IB is an enlarged view of part A of FIG. 1 A, illustrating a pattern of the optical cable engaged with fixing structures;

FIG. 2A is a perspective view of the exterior and interior structures of a first member (on the left and right sides of FIG. 2 A, respectively) in a fixing structure according to an embodiment of the present disclosure;

FIG. 2B is a perspective view of the exterior and interior structures of a second member (on the left and right sides of FIG. 2B, respectively) in the fixing structure according to an embodiment of the present disclosure;

FIG. 3 is a plan view illustrating the exterior and interior of a fixing structure according to an embodiment of the present disclosure;

FIG. 4 is a sectional view illustrating assembly of the first and second members of a fixing structure according to an embodiment of the present disclosure;

FIGS. 5A and 5B are views illustrating a pre-engagement state of the first member, and a post-engagement state of the first member, respectively in a fixing structure according to the present disclosure, when an optical fiber passes through the fixing structure in an upper and lower 2-row parallel contact manner;

FIG. 6A illustrates a grid-type sensor network woven with a single optical cable by means of structures according to the present disclosure, with a circled drawing illustrating discharge of the optical cable arranged in an upper and lower 2-row parallel contact manner from a path of a fixing structure;

FIG. 6B is a view illustrating a state in which the first member is removed from the fixing structure shown in a circle in FIG. 6A;

FIG. 7 is a bottom view of the fixing structure, when a grid is formed;

FIG. 8 is a view illustrating a fixing jig containing a plurality of fixing structures in a state where the optical cable is formed into a grid structure;

FIG. 9 is a view illustrating an assembly operation during formation of a network using a fixing jig and fixing structures; FIG. 10 illustrates a state in which the first members of the fixing structures illustrated in FIG. 8 are engaged simultaneously; and

FIG. 11 is a schematic view illustrating a system for establishing a network, which enables simultaneous engagement and simultaneous removal by use of a fixing jig and fixing 5 structures so that a network may be formed in a grid structure by simultaneously arranging a single optical cable in a plurality of rows.

Throughout the drawings, like reference numerals will be understood to refer to like parts, components, and structures.

DETAILED DESCRIPTION

10 The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the disclosure as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skilled in the art will recognize that various changes and modifications of the

15 embodiments described herein can be made without departing from the scope and spirit of the disclosure.

FIG. 1A is a view illustrating a state in which a grid-type sensor network 100 is unfolded, the grid-type sensor network 100 being woven with a single optical cable 10 using fixing structures 20 that fix grids. FIG. IB is an enlarged view of part A of FIG. 1A,

20 illustrating a pattern of the optical cable 10 engaged with the fixing structures 20.

In the case where the optical cable network 100 is fabricated in a diamond-shaped network structure by means of the small fixing structures 20, the optical cable 10 does not get tangled. Therefore, there is no need for using an additional structure such as a paper box during packaging, and the volume of the sensor network 100 may be minimized, thereby

25 facilitating transportation.

Referring to FIGS. 2A, 2B, and 3, a fixing structure 20 of the present disclosure includes a first member 21 and a second member 22. Protrusions 21d and 22d protrude respectively from inner surfaces of the first member 21 and the second member 22, and through holes 21e and 22e are formed respectively on the inner surfaces of the first member

30 21 and the second member 22. Thus, the first member 21 may be engaged with the second member 22 by inserting the protrusion 21d of the first member 21 into the through hole 22e of the second member 22 and inserting the protrusion 22d of the second member 22 into the through hole 21 e of the first member 21. FIG. 4 is a sectional view of the first and second members 21 and 22, seen from the bottom of FIGS. 2 A and 2B, illustrating an embodiment of assembling the first and second members 21 and 22 in the above-described manner.

FIGS. 5 A and 5B are views respectively illustrating a pre-assembly state and post- assembly state of the first member 21 of the fiber network grid fixing structure 20 according to the present disclosure, when two strands of the optical cable 10 pass through the fixing structure 20 in an upper and lower 2-row parallel contact manner. Specifically, the single optical cable 10 passes through an optical cable container 22c formed in the second member 22 of the fixing structure 20, in one row, and then passes through the container 22c, on the optical cable 10 placed in the row, so that the optical cable 10 may form a grid in a zig-zag manner. Thus, the optical cable 10 is arranged in upper and lower two rows in parallel in the container 22c, without being twisted. The state in which the first member 21 of the fixing structure 20 is fixed on the second member 22 is illustrated in FIG. 5B.

Since the at least one protrusion 21b or 22b is formed in each of the optical cable containers 21c and 22c of the first and second members 21 and 22, the protrusions 21b and 22b press against the surface of the optical cable 10, thereby preventing slip-off of the optical cable 10.

Welding protrusions 21a and 22a may be formed respectively on assembly surfaces of the first and second members 21 and 22. After the first and second members 21 and 22 are fixedly engaged with each other, the first and second members 21 and 22 may further be fixed by means of an ultrasonic welder in order to fix them more tightly. As the first member 21 and the second member 22 are welded to each other by heat generated from vibrations of the ultrasonic welder, they are tightly fixed to each other. These vibrations are also transferred to the optical fiber 10, and thus the optical fiber 10 may be fixed to the fixing structures 20 without damage to the optical fiber 10.

Because the fixing structure according to an embodiment of the present disclosure is fixed through engagement between the protrusions and the through holes, pressing of the protrusions, and fusion, the fixing structure is very robust without using an additional adhesive. Therefore, it is difficult to disassemble the fixing structure, and even though a force is applied to the fixing structure to disassemble the fixing structure, the optical fiber slipped off from the fixing structure may be vulnerable to optical loss because it closely contacts the fixing structure. Moreover, even though an intruder disassembles the fixing structure, the intruder should remove the optical fiber attached in two parallel upper and lower rows to pass through the optical cable network. In this case, the optical cable is damaged and thus intrusion may be indicated fast.

FIG. 6 A illustrates the sensor network 100 completed in a uniform diamond-shaped fiber network grid structure, which has been unfolded, and provides an enlarged view of a part of the sensor network 100. Although the optical cable 10 is arranged with its strands contacting each other in parallel in a fixing structure 20, the optical cable coming out from the fixing structure 20 is branched without contact in order to form a grid. It is noted from the enlarged view of the fixing structure 20 circled in FIG. 6A that two upper and lower rows of the optical cable 10 are brought into close contact with each other to the ends of a path of the fixing fixture. The 2-row optical cable 10 in the fixing structure 20 are shown in FIG. 6B, with the first member removed for the convenience. FIG. 7 is a bottom view of the fixing structure, when the grid structure is formed.

A single optical cable may be used to form a grid structure simultaneously in a plurality of rows by adopting the layout of a fiber network and the fixing structures according to the present disclosure. In an embodiment, FIG. 8 illustrates a state in which a grid structure is woven with a single optical cable simultaneously in a plurality of rows, by means of a plurality of fixing jigs and a plurality of fixing structures in each fixing jig.

A fixing jig 200 is provided with a plurality of grooves for accommodating a plurality of fixing structures 20. A grid-type fiber network may be formed by arranging the plurality of fixing jigs 200 accommodating the second members 22 of the fixing structures 20, apart from each other in a horizontal direction, and weaving the single optical cable 10 in a zigzag manner so that the optical cable 10 may twice pass through the optical cable containers 22c of the arranged second members 22, in one row strand at each time, and thus may be arranged in two upper and lower parallel contacting rows in the optical cable containers 22c. Subsequently, the first members 21 of the plurality of fixing structures 20 are placed on the optical cable 10 arranged in the second members 22, and a cylindrical pressing member 300 is lowered and simultaneously presses the first members 21 of the plurality of fixing structures 20. Thus, the protrusions 21d formed on the inner assembly surfaces of the fixing structures 20 are accommodated in the corresponding through holes 22e, thereby simultaneously engaging the first members 21 with the second members 22.

Referring to FIG. 9, regarding an assembly sequence of a fixing jig 200 and a fixing structure 20 during network formation, the second member 22 of the fixing structure 20 is placed inside the fixing jig 20, and the optical cable 10 is arranged in two upper and lower parallel rows on the second member 22. Herein, the optical cable 10 is maintained safely in two rows, due to an inner path of the fixing jig 200. Then, the first member 21 of the fixing structure 20 is provided on the second member 22, and the first and second members 21 and 22 are fixed by pressing them with the pressing member 300.

FIG. 10 illustrates the fixing jig 200 that contains the fixing structure 20 fixing the optical cable 10.

FIG. 11 illustrates a method for forming a network, which enables simultaneous engagement and simultaneous removal so that a grid structure may be woven with one optical cable simultaneously in a plurality of rows, by means of fixing jigs and fixing structures. During engagement, the fixing structures 20 connected to an engagement structure 700 which moves along an engagement rail 600 are lowered and engaged simultaneously. The sensor network 100 fabricated in this manner is removed from the fixing jigs 200 simultaneously by means of a removal structure 400 moving along a removal rail 500 and transferred. Then, the fixing structures 20 are more tightly fixed by welding the welding protrusions 21a and 22a of the first and second members 21 and 22 with an ultrasonic welder.

The method for forming a network according to the present disclosure adopts a simultaneous engagement and simultaneous removal mechanism for fixing jigs and fixing structures without twisting an optical cable. Therefore, the optical cable may be readily arranged in a plurality of rows into a network and a time taken to fabricate the network may be reduced remarkably.

As is apparent from the foregoing description, the optical cable sensor network of the present disclosure does not suffer from optical loss caused by fusion-contact due to a structure in which a single optical cable is fixed in parallel in a contact manner by means of small fixing structures. Further, since the sensor network is formed readily by arranging the optical cable simultaneously in a plurality of rows without twisting the optical cable, a fabrication time is reduced remarkably. The sensor network is difficult to disassemble, thus having an improved sensor sensitivity.

While the disclosure has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the appended claims and their equivalents.