Abstract:
Disclosed is a bio-signal monitoring system which includes a bio-signal transfer device which measures and analyzes a bio-signal and sends the analyzed bio-signal and first identification information; a reception device which includes at least one or more receivers, each receiver transferring information received from the bio-signal transfer device and second identification information; and a monitoring server which analyzes information received from each receiver and judges location and physical condition of a user, wherein the first identification information includes ID of the user and ID of the bio-signal and the second identification information includes ID of the receiver.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    A claim for priority under 35 U.S.C. §119 is made to Korean Patent Application No. 10-2011-0139310 filed Dec. 21, 2011, in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference. 
       BACKGROUND 
       [0002]    The inventive concepts described herein relate to a bio-signal transfer device, a bio-signal monitoring system, and a method using the same. 
         [0003]    A bio-signal measuring and analyzing system may be used to check a physical condition of a user and to recognize the emergency such as sudden cardiogenic shock, arrhythmia, and the like. For example, electro-cardiogram (ECG) may be used as a bio-signal to diagnose the emergency. 
         [0004]    The cases that a wireless information transfer technique is applied to a medical field may increase along with development of the communication technology. In a bio-signal monitoring system, information may be collected in a wireless transmission and reception manner to cope with a physical condition and the emergency checked through a bio-signal. However, a bio-signal measured in real time may have a large information amount. Thus, a large transfer amount may be required to transfer information in a wireless manner. This may cause overload easily. Also, in the event that communication is made in a Bluetooth manner, hindrance may be generated due to interference at a dense space of users. This may make it difficult to collect information. 
       SUMMARY 
       [0005]    Example embodiments of the inventive concept provide a bio-signal monitoring system which comprises a bio-signal transfer device which measures and analyzes a bio-signal and sends the analyzed bio-signal and first identification information; a reception device which includes at least one or more receivers, each receiver transferring information received from the bio-signal transfer device and second identification information; and a monitoring server which analyzes information received from each receiver and judges location and physical condition of a user, wherein the first identification information includes ID of the user and ID of the bio-signal and the second identification information includes ID of the receiver. 
         [0006]    In example embodiments, the ID of the bio-signal includes a transfer time of the bio-signal. 
         [0007]    In example embodiments, the bio-signal transfer device comprises at least one electrode which is attached to a body of the user to measure a first bio-signal; a bio-signal processing module which is attached to a body of the user to measure a second bio-signal, generates a bio analysis signal by analyzing the first bio-signal and the second bio-signal, and sends the bio analysis signal and the first identification signal; and a lead line which connects the electrode and the bio-signal processing module. 
         [0008]    In example embodiments, the bio analysis signal includes a breathing rate and whether arrhythmia is generated. 
         [0009]    In example embodiments, the bio analysis signal further includes a body temperature. 
         [0010]    In example embodiments, the bio analysis signal includes a danger signal associated with whether a body of the user is abnormal. 
         [0011]    In example embodiments, the monitoring server outputs an emergence signal to the outside in response to the danger signal. 
         [0012]    In example embodiments, the bio-signal processing module comprises a connector which is connected to the lead line to transfer the first bio-signal; a sensor which measures the second bio-signal; an analog signal processing unit which removes noise from the first and second bio-signals to amplify amplitudes of the first and second bio-signals; a digital signal processing unit which analyzes the bio-signal amplified by the analog signal processing unit; and an information transmission unit which sends the bio analysis signal analyzed by the digital signal processing unit and the first identification information. 
         [0013]    In example embodiments, the analog signal processing unit comprises a signal collector which combines the first bio-signal and the second bio-signal; a filter which removes noise from a bio-signal combined by the signal collector; and an amplifier which amplifies the bio-signal provided from the filter. 
         [0014]    In example embodiments, the signal collector combines the first and second bio-signals based on a difference between the first bio-signal and the second bio-signal. 
         [0015]    In example embodiments, the digital signal processing unit comprises a microcontroller unit which converts a bio-signal amplified by the analog signal processing unit into a digital signal and analyzes the converted bio-signal; and a memory which stores an analyzed result and the converted bio-signal provided from the microcontroller unit. 
         [0016]    In example embodiments, the bio-signal transfer device sends information discretely. 
         [0017]    In example embodiments, the bio-signal transfer device sends information periodically. 
         [0018]    In example embodiments, an information transfer period of the bio-signal transfer device is variable. 
         [0019]    In example embodiments, the monitoring server compares the number of receivers sending the information with a limit value and adjusts the strength of a transmission signal of the bio-signal transfer device. 
         [0020]    Example embodiments of the inventive concept also provide a bio-signal transfer device which comprises at least one electrode which is attached to a body of a user to measure a first bio-signal; and a bio-signal processing module which is attached to the body of the user to measure a second bio-signal, generates a bio analysis signal by analyzing the first and second bio-signals, and sends the bio analysis signal and the first identification information, wherein the first identification information includes ID of the user and ID of the bio-signal. 
         [0021]    Example embodiments of the inventive concept also provide a monitoring method which comprises measuring and analyzing a bio-signal of a user; sending the analyzed bio-signal to at least one receiver with first identification information; sending information provided from the receiver and second identification information; adjusting the strength of a signal transferred to the receiver according to a result obtained by comparing the number of receivers sending the information with a limit value; and judging a physical condition and location information of the user by analyzing information provided from the receiver, wherein the first identification information includes ID of the user and ID of the bio-signal and the second identification information includes ID of the receiver. 
         [0022]    In example embodiments, the monitoring method further comprises outputting an emergence signal to the outside when a body of the user is judged to be abnormal according to the physical condition of the user. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0023]    The above and other objects and features will become apparent from the following description with reference to the following figures, wherein like reference numerals refer to like parts throughout the various figures unless otherwise specified, and wherein 
           [0024]      FIG. 1  is a diagram schematically illustrating a bio-signal monitoring system according to an embodiment of the inventive concept. 
           [0025]      FIG. 2  is a detailed block diagram illustrating a bio-signal transfer device according to an embodiment of the inventive concept. 
           [0026]      FIG. 3  is a diagram illustrating a bio-signal transfer device in  FIG. 2 . 
           [0027]      FIG. 4  is a block diagram schematically illustrating a bio-signal processing module according to an embodiment of the inventive concept. 
           [0028]      FIG. 5  is a block diagram schematically illustrating a reception device in  FIG. 1  according to an embodiment of the inventive concept. 
           [0029]      FIG. 6  is a diagram schematically illustrating a bio-signal monitoring system according to an embodiment of the inventive concept. 
           [0030]      FIG. 7  is a flowchart illustrating a monitoring method according to an embodiment of the inventive concept. 
       
    
    
     DETAILED DESCRIPTION 
       [0031]    Embodiments will be described in detail with reference to the accompanying drawings. The inventive concept, however, may be embodied in various different forms, and should not be construed as being limited only to the illustrated embodiments. Rather, these embodiments are provided as examples so that this disclosure will be thorough and complete, and will fully convey the concept of the inventive concept to those skilled in the art. Accordingly, known processes, elements, and techniques are not described with respect to some of the embodiments of the inventive concept. Unless otherwise noted, like reference numerals denote like elements throughout the attached drawings and written description, and thus descriptions will not be repeated. In the drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. 
         [0032]    It will be understood that, although the terms “first”, “second”, “third”, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the inventive concept. 
         [0033]    Spatially relative terms, such as “beneath”, “below”, “lower”, “under”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature&#39;s relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary terms “below” and “under” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated  90  degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. 
         [0034]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Also, the term “exemplary” is intended to refer to an example or illustration. 
         [0035]    It will be understood that when an element or layer is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another element or layer, it can be directly on, connected, coupled, or adjacent to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly connected to”, “directly coupled to”, or “immediately adjacent to” another element or layer, there are no intervening elements or layers present. 
         [0036]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this inventive concept belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and/or the present specification and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
         [0037]      FIG. 1  is a diagram schematically illustrating a bio-signal monitoring system according to an embodiment of the inventive concept. Referring to  FIG. 1 , a bio-signal monitoring system  1000  may include a bio-signal transfer device  1100 , a reception device  1200 , and a monitoring server  1300 . 
         [0038]    The bio-signal transfer device  1100  may measure a bio-signal. The bio-signal transfer device  1100  may analyze the measured bio-signal. The bio-signal transfer device  1100  may add first identification information to the analyzed bio-signal to send it. 
         [0039]    The reception device  1200  may receive information sent from the bio-signal transfer device  1100 . The reception device  1200  may include at least one receiver. A receiver may be disposed within an appointed period. Each receiver receiving information may add second identification information to the received information to send it. 
         [0040]    The monitoring server  1300  may combine and analyze information received from each reception device to comprehend physical condition and location information of a user. 
         [0041]      FIG. 2  is a detailed block diagram illustrating a bio-signal transfer device according to an embodiment of the inventive concept. Referring to  FIG. 2 , a bio-signal transfer device  1100  may include a first electrode  1110   a,  a first lead line  1111   a,  a second electrode  1110   b,  a second lead line  1111   b,  and a bio-signal processing module  1120 . 
         [0042]    The bio-signal transfer device  1100  may measure a bio-signal. In example embodiments, the bio-signal transfer device  1100  may measure a bio-signal generated by a physiological potential difference of a body of a user. The bio-signal measured by the bio-signal transfer device  1100  may be various. For example, the bio-signal may include electro-cardiogram (ECG), electro-encephalogram (EEG), electro-myogram (EMG), galvanic skin reflex (GSR), electro-oculography (EOG), Pulse plethysmography (PPG), amount of exercise on breathing rate and time, and the like. The inventive concept will be described on the basis of the electro-cardiogram (ECG). However, the inventive concept is not limited thereto. The bio-signal transfer device  1100  may analyze a measured bio-signal. The bio-signal transfer device  1100  may transfer the analyzed signal. The bio-signal transfer device  1100  may be attached to a user. In this case, the bio-signal transfer device  1100  may be a patch-type device. 
         [0043]    The bio-signal transfer device  1100  may include at least one or more electrodes and lead lines. Each electrode may be connected to the bio-signal processing module  1120  through a lead line. In example embodiments, two electrodes  1110   a  and  1110   b  and two lead lines  1111   a  and  1111   b  may be used. However, the inventive concept is not limited thereto. 
         [0044]    The first electrode  1110   a  may be connected to the bio-signal processing module  1120  through the first lead line  1111   a.  The second electrode  1110   b  may be connected to the bio-signal processing module  1120  through the second lead line  1111   b.  The first and second electrodes  1110   a  and  1110   b  may be a disposable electrode. The first and second electrodes  1110   a  and  1110   b  may be attached to a body of a user to measure a bio-signal. 
         [0045]    The bio-signal processing module  1120  may measure a bio-signal. The bio-signal processing module  1120  may filter the measured bio-signal via a filter. The bio-signal processing module  1120  may analyze the filtered signal. The bio-signal processing module  1120  may send the analyzed signal. The bio-signal processing module  1120  may include a connector  1121 , an analog signal processing unit  1123 , a digital signal processing unit  1124 , and an information transfer unit  1125 . 
         [0046]    The connector  1121  may be connected with at least one lead line. The connector  1121  may be connected to the bio-signal processing module  1120  through the lead line. In example embodiments, the connector  1121  may be connected to two lead lines  1111   a  and  1111   b.  However, the inventive concept is not limited thereto. For example, the connector  1121  may be connected with one lead line. Also, the connector  1121  can be connected with four or eight lead lines. A bio-signal measured by an electrode may be transferred to the connector  1121  through a lead line. The connector  1121  may transmit the input bio-signal to the analog signal processing unit  1123 . 
         [0047]    The sensor  1122  may measure a bio-signal. The sensor  1122  may be a disposable electrode. For example, the sensor  1122  may be configured the same as first and second electrodes. A bio-signal measured by the sensor  1122  may be various. For example, a bio-signal may include electro-cardiogram (ECG), electro-encephalogram (EEG), electro-myogram (EMG), galvanic skin reflex (GSR), electro-oculography (EOG), Pulse plethysmography (PPG), amount of exercise on breathing rate and time, and the like. The sensor  1122  may measure a bio-signal in various manners. For example, the sensor  1122  may measure a bio-signal generated due to a physiological potential difference of a body of a user. However, the inventive concept is not limited thereto. The sensor  1122  may send the measured bio-signal to the analog signal processing unit  1123 . 
         [0048]    The analog signal processing unit  1123  may remove noise of bio-signals measured by the sensor  1122 , the first electrode  1110   a,  and the second electrode  1110   b.  The analog signal processing unit  1123  may amplify and output a noise-removed bio-signal. 
         [0049]    The digital signal processing unit  1124  may receive a bio-signal amplified by the analog signal processing unit  1123 . The digital signal processing unit  1124  may analyze a bio-signal to output an analyzed result. In example embodiments, the digital signal processing unit  1124  may analyze an electro-cardiogram signal to output whether or not arrhythmia is generated and its type. Alternatively, the digital signal processing unit  1124  may analyze an electro-cardiogram signal to output a breathing rate. Also, the digital signal processing unit  1124  may output a danger signal when an analyzed result of a bio-signal indicates that a body of a user is abnormal. Since the analyzed result has the information amount less than a raw bio-signal, it may be advantageous to transfer. 
         [0050]    The information transfer unit  1125  may transfer the analyzed result of the digital signal processing unit  1124  in a wireless manner. The information transfer unit  1125  may add first identification information to the analyzed result of the digital signal processing unit  1124  to send it. The first identification information may include identification information of a user (hereinafter, referred to as user ID). The first identification information may include identification information of a currently transferred analyzed result (hereinafter, referred to as data ID). The data ID may be a time when a currently analyzed result is transferred. 
         [0051]    Thus, the bio-signal transfer device  1100  according to an embodiment of the inventive concept may measure and analyze a bio-signal. A signal having the information amount reduced through analysis may be transmitted together with the first identification information by wireless. 
         [0052]      FIG. 3  is a diagram illustrating a bio-signal transfer device in  FIG. 2 . Referring to  FIG. 3 , a bio-signal transfer device may include a first electrode  2110   a,  a first lead line  2111   a,  a second electrode  2110   b,  a second lead line  2111   b,  and a bio-signal processing module  2120 . 
         [0053]    In example embodiments, the first electrode  2110   a,  the second electrode  2110   b,  and the bio-signal processing module  2120  may measure potentials of points corresponding to standard limb leads. The first electrode  2110   a,  the second electrode  2110   b,  and the bio-signal processing module  2120  may be attached to a body of a user. The first electrode  2110   a  may correspond to a left arm electrode, the second electrode  2110   b  to a left foot electrode, and the bio-signal processing module  2120  to a right arm electrode. 
         [0054]    A potential difference between the bio-signal processing module  2120  and the first electrode  2110   a  may indicate a lead I signal. A potential difference between the bio-signal processing module  2120  and the second electrode  2110   b  may indicate a lead II signal. A potential difference between the first electrode  2110   a  and the second electrode  2110   b  may indicate a lead III signal. It is possible to measure a bio-signal easily using the lead signals. Bio-signals measured by the first electrode  2110   a,  the second electrode  2110   b,  and the bio-signal processing module  2120  may be processed and analyzed by the bio-signal module  2120 . The analyzed information may be sent to the outside together with the first identification information. 
         [0055]    Thus, the bio-signal transfer device according to an embodiment of the inventive concept may detect a bio-signal by measuring a potential difference between electrodes. The information amount of the detected bio-signal may be reduced through analysis, and then may be transferred to the outside. 
         [0056]      FIG. 4  is a block diagram schematically illustrating a bio-signal processing module according to an embodiment of the inventive concept. Referring to  FIG. 4 , a bio-signal processing module  3100  may include a connector  3110 , a sensor  3120 , an analog signal processing unit  3130 , a digital signal processing unit  3140 , and an information transfer unit  3150 . 
         [0057]    The connector  3110  may connect at least one lead line to the bio-signal processing module  3100 . A bio-signal detected by an electrode may be transferred to the connector  3110  through a lead line. The connector  3110  may transfer the input bio-signal to the analog signal processing unit  3130 . 
         [0058]    The sensor  3120  may detect a bio-signal. The sensor  3120  may be attached to a body of a user. The sensor  3120  may measure a potential of an attached point. 
         [0059]    The analog signal processing unit  3130  may include a signal collector  3131 , a filter  3132 , and an amplifier  3133 . The analog signal processing unit  3130  may remove noise of bio-signals measured by the sensor  3120  and an electrode to amplify it. 
         [0060]    The signal collector  3131  may receive a bio-signal measured by the sensor  3120 . The signal collector  3131  may receive a bio-signal detected by an electrode through the connector  3110 . The signal collector  3131  may combine bio-signals provided from the sensor  3120  and the connector  3110 . The signal collector  3131  may send the combined information to the filter  3132 . For example, the signal collector  3131  may provide lead I, II, and III signals to the filter  3132  based on a difference of potentials of respective points of a body input from the sensor  3120  and the connector  3110 . If a potential difference between electrodes is used as a bio-signal, common mode noise may be removed. Thus, it is possible to obtain a signal with the high reliability. 
         [0061]    The filter  3132  may remove noise of a bio-signal input from the signal collector  3131 . The bio-signal may have a high noise property due to a small size. Also, since a body is organized by organic combination of organs, it is difficult to measure a signal associated with only a point. For example, a breathing signal may be measured together upon measuring of electro-cardiogram (ECG), or electro-myogram (EMG) may be measured together upon measuring of electro-encephalogram (EEG). Thus, a filter may be required to separate only a target signal from a measured signal. The filter  3132  may output a noise-removed bio-signal. In example embodiments, the filter  3132  may be placed between the signal collector  3131  and the amplifier  3133 . However, the inventive concept is not limited thereto. For example, the filter  3132  may be placed following the amplifier  3133  to remove noise of an amplified signal. 
         [0062]    The amplifier  3133  may amplify a bio-signal provided from the filter  3132 . A magnitude of a bio-signal may be very small, for example, below 1 mV. Thus, amplification of a bio-signal may be required to analyze a bio-signal. The amplifier  3133  may output an amplified bio-signal. 
         [0063]    The digital signal processing unit  3140  may include a microcontroller unit (MCU)  3141  and a memory  3142 . The digital signal processing unit  3140  may convert a bio-signal provided from the analog signal processing unit  3130  into a digital signal to analyze the converted bio-signal. 
         [0064]    The MCU  3141  may convert a bio-signal provided from the analog signal processing unit  3130  into a digital signal through an analog-to-digital converter. The MCU  3141  may include a digital filter. The digital filter may remove noise that is not removed by an analog filter. 
         [0065]    The MCU  3141  may analyze a noise-removed bio-signal. In example embodiments, the MCU  3141  may analyze arrhythmia of a user and its type using the electro-cardiogram (ECG) signal. The MCU  3141  may analyze cardiogenic shock and cardiogenic disease of a user using the electro-cardiogram (ECG) signal. The MCU  3141  may store a bio-signal and an analyzed result at the memory  3142 . Information stored at the memory  3142  may be used when a close analysis is required. The MCU  3141  may transfer the analyzed result to the information transfer unit  3150 . 
         [0066]    The information transfer unit  3150  may send the analyzed result input from the MCU  3141  by wireless. The information transfer unit  3150  may send first identification information together with the analyzed result. The first identification information may include user ID and data ID. The data ID may include a transfer time to identify a user associated with the currently transferred analyzed information. Also, since currently transferred analyzed information is sorted chronologically, it may be advantageous to analyze. 
         [0067]    A bio-signal transfer device according to an embodiment of the inventive concept may be attached to a body to measure a bio-signal of a user in real time. The bio-signal transfer device may analyze a measured bio-signal to send only desired information. Thus, it is possible to reduce the amount of information to be transferred. Also, the bio-signal transfer device may perform a close analysis operation using identification information (e.g., time information of a bio-signal) as well as an analyzed bio-signal 
         [0068]      FIG. 5  is a block diagram schematically illustrating a reception device in  FIG. 1  according to an embodiment of the inventive concept. Referring to  FIG. 5 , a reception device  1200  may include at least one or more receivers, each of which an information receiving unit and a transmission unit. Below, a reception device according to an embodiment of the inventive concept will be described using a first receiver  1210 . The remaining receivers may be configured the same as the first receiver  1210 . 
         [0069]    The first receiver  1210  may receive information transferred from a bio-signal transfer device. The first receiver  1210  may send input information and second identification information to a monitoring server  1300 . 
         [0070]    An information receiving unit  1211  may receive information transferred from the bio-signal transfer device  1100 . The information receiving unit  1211  may provide input information to a transmission unit  1212 . 
         [0071]    The transmission unit  1212  may send information transferred from the information receiving unit  1211  together with the second identification information to the monitoring server  1300 . The second identification information may include an inherent ID of each receiver. This may make it possible for the monitoring server  1300  to comprehend a location of information received from the bio-signal transfer device  1100 . 
         [0072]      FIG. 6  is a diagram schematically illustrating a bio-signal monitoring system according to an embodiment of the inventive concept. Referring to  FIG. 6 , a bio-signal monitoring system  4000  may include a bio-signal transfer device  4100 , a reception device  4200 , and a monitoring server  4300 . The reception device  4200  may include at least one receiver. 
         [0073]    The bio-signal transfer device  4100  may be attached to a user. The bio-signal transfer device  4100  may measure a bio-signal of the user. The bio-signal transfer device  4100  may analyze the measured bio-signal. The bio-signal transfer device  4100  may transfer the analyzed bio-signal and first identification information. 
         [0074]    The bio-signal transfer device  4100  may transfer information discretely or periodically. Compared with the case that information continues to be transferred, the bio-signal transfer device  4100  may be efficient in a power. Since information is transferred periodically, it may be possible to recognize omission of information easily. An information transfer period may be variable. For example, the information transfer period may be set to be long when the night where a location of a user is scarcely varied. Information transfer periods of different users may be set to be different from one another. When the monitoring server  4300  issues a command indicating reception of information, information may be instantly transferred regardless of an information transfer period. 
         [0075]    An information transfer method of the bio-signal transfer device  4100  may not be limited to this disclosure. In example embodiments, the bio-signal transfer device  4100  may transfer information in a simple RF manner. In example embodiments, the bio-signal transfer device  4100  may transmit a less amount of information discretely. Thus, power consumption may be reduced by using a simple RF manner in which a complicated protocol is not used. However, the inventive concept is not limited thereto. 
         [0076]    Information transferred from the bio-signal transfer device  4100  may be non-directional. Thus, information may be transmitted to a plurality of receivers within a transmission field. In example embodiments, it is assumed that information is transferred to first to third receivers  4210  to  4230 . 
         [0077]    The first to third receivers  4210  to  4230  may receive information from m the bio-signal transfer device  4100 . The first to third receivers  4210  to  4230  may add second identification information to input information, respectively, to transfer resultant signals to the monitoring server  4300 . 
         [0078]    The monitoring server  4300  may receive information from the first to third receivers  4210  to  4230 . The monitoring server  4300  may monitor a physical condition of a user using the input bio-signal information. The monitoring server  4300  may sort and classify bio-signal information using the first identification information. 
         [0079]    The monitoring server  4300  may discriminate receives, which receive information from the bio-signal transfer device  4100 , using the second identification information. The monitoring server  4300  may estimate a location of a user using locations of receivers receiving information from the bio-signal transfer device  4100 . 
         [0080]    In example embodiments, the monitoring server  4300  may use the estimated location of the user as an average location of receivers receiving information from the bio-signal transfer device  4100 . However, the inventive concept is not limited thereto. 
         [0081]    If a transmission field of the bio-signal transfer device  4100  is excessively wide, faraway receivers may receive signals. That is, the number of receivers receiving information may increase. Upon location estimation, an error may arise due to a distance difference between the bio-signal transfer device  4100  and receivers receiving information. If a transmission field of the bio-signal transfer device  4100  is excessively narrow, receivers close to the bio-signal transfer device  4100  may not receive signals. Thus, it is difficult to estimate a location. 
         [0082]    To solve the above-described problems, the monitoring server  4300  may have upper limit and lower limit. If the number of receivers receiving information from the bio-signal transfer device  4100  is over the upper limit, the monitoring server  4300  may issue a command indicating a decrease in the strength of transmission. The bio-signal transfer device  4100  receiving the command may reduce a transmission field by lowering the strength of transmission signal. As the transmission field is reduced, the number of receivers receiving information from the bio-signal transfer device  4100  may decrease. Thus, it is possible to estimate a location of a user more exactly. 
         [0083]    If the number of receivers receiving information from the bio-signal transfer device  4100  is below the lower limit, the monitoring server  4300  may issue a command indicating an increase in the strength of transmission. The bio-signal transfer device  4100  receiving the command may expand a transmission field by increasing the strength of transmission signal. As the transmission field is expanded, the number of receivers receiving information from the bio-signal transfer device  4100  may increase. Thus, it is possible to estimate a location of a user more exactly. 
         [0084]    In the even that input bio-signal information includes a danger signal, the monitoring server  4300  may judge a body of the user to be abnormal. The monitoring server  4300  may send the estimated location and bio-signal information of the user to the outside, for example, a medical center to immediately cope with a sudden situation of a body of the user. 
         [0085]    If no bio-signal information is received during a predetermined time, the monitoring server  4300  may issue a command indicating an increase in the strength of transmission. Nevertheless, if no bio-signal information is received during a predetermined time, the monitoring server  4300  may judge a body of the user to be abnormal. At this time, the monitoring server  4300  may output an emergency signal. The emergency signal may include warning through an output device such as alarm, image notification, and the like. Also, the emergency signal may include just recently estimated location and bio-signal information of the user. The monitoring server  4300  may send the emergency signal to the outside, for example, a medical center to immediately cope with a sudden situation of a body of the user. 
         [0086]    The bio-signal monitoring system according to an embodiment of the inventive concept may be installed at various places such as a private residence, a hospital, a reception center, a nursing home, and the like. In this case, it is possible to analyze physical conditions and locations of many users. 
         [0087]    The bio-signal monitoring system according to an embodiment of the inventive concept may continuously monitor physical condition and location information of a user. The bio-signal monitoring system may finely estimate location information of a user by adjusting the strength of signal. Also, the bio-signal monitoring system may immediately cope with a situation that a body of the user is abnormal, using danger signal and time information. 
         [0088]      FIG. 7  is a flowchart illustrating a monitoring method according to an embodiment of the inventive concept. Referring to  FIG. 7 , in operation S 100 , a bio-signal of a user may be measured and analyzed. The bio-signal may include an electro-cardiogram (ECG) signal. A breathing rate, arrhythmia, a physical condition, and the like may be analyzed through the bio-signal. In operation S 110 , the analyzed bio-signal may be sent with first identification information, that is, user ID and data ID. 
         [0089]    In operation S 120 , each reception device receiving information may send input information and own identification information to a monitoring server  1300 . In operation S 130 , the monitoring server  1300  may compare the number of receivers sending information with a lower limit value. If the number of receivers sending information is below the lower limit value, in operation S 131 , the monitoring server  1300  may issue a command indicating an increase of the strength of a transmission signal. 
         [0090]    In operation S 140 , the monitoring server  1300  may compare the number of receivers sending information with an upper limit value. If the number of receivers sending information is over the upper limit value, the monitoring server  1300  may issue a command indicating a decrease of the strength of a transmission signal. 
         [0091]    When the number of receivers sending information is between the lower limit value and the upper limit value, in operation S 150 , the monitoring server  1300  may analyze input information to judge physical condition and location information of the user. If a body of the user is judged to be abnormal, the monitoring server  1300  may take a corresponding emergence action. 
         [0092]    With the monitoring method according to an embodiment of the inventive concept, it is possible to continuously monitor physical condition and location information of a user. Also, it is possible to finely estimate location information of a user by adjusting the strength of signal. Accordingly, it is possible to immediately cope with a situation that a body of the user is abnormal, using danger signal and time information. 
         [0093]    The inventive concept may be modified or changed variously. For example, a bio-signal transfer device  1100 , a reception device  1200 , and a monitoring server  1300  may be changed or modified variously according to environment and use. 
         [0094]    While the inventive concept has been described with reference to exemplary embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it should be understood that the above embodiments are not limiting, but illustrative.