Health Monitoring System for Nursing Homes with...

Research ArticleHealth Monitoring System for Nursing Homes with LightweightSecurity and Privacy Protection

Yursquoe Jiang12 and Jiaxiang Liu2

1School of Computer and Information and the University Key Laboratory of Intelligent Perception and Computing of Anhui ProvinceAnqing Normal University Anqing 246011 China2School of Computer and Information Anqing Normal University Anqing 246011 China

Correspondence should be addressed to Yursquoe Jiang wsxiaoe163com

Received 9 November 2016 Revised 21 December 2016 Accepted 23 January 2017 Published 7 March 2017

Academic Editor Liangmin Wang

Copyright copy 2017 Yursquoe Jiang and Jiaxiang Liu This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

With the rapid growth of aged population in China it is urgent to design a safe and effective monitoring system for the nursinghomes An optimized scheme and high performance security and privacy protection for monitoring system have already becomethe focus studied especially So this paper proposed a health monitoring system with lightweight security and privacy protectionfor nursing homes Dual-band RFID virtual routing location algorithm and diet and exercise data collection based on RFID wereadopted to obtain the location and health information And that fused a mobile authentication protocol based on Hash functionto realize security access and privacy protection which can improve security and reduce the complexity of calculation and theimplementation cost compared with the typical authentication protocols The experiment results show that the ratio of relativenetwork delay is below 35The systemhas strong real-time high securitymore comprehensive data and lower cost of computationand communication It can satisfy the requirements of health monitoring for nursing homes

1 Introduction

It is estimated that China will enter the aging society Howto provide more comprehensive pension services becomesmore and more urgent As families and community canonly provide limited elderly services a tendency to meetthe rocketing demands is to promote healthy monitoringsystem for nursing homes As environment in nursing homesis complex managers cannot focus on every one of theelderly people So the challenge is to provide location serviceand health service in the event of dangerous conditions [1ndash5] With the rapid development of monitoring technologyRFID get more attention due to its advantage such asunique identification moveable identification multitargetsidentification and good environmental adaptability In aword a safe and effective monitoring system based on RFIDfor the nursing homes will be required urgently

Existing monitoring systems based on RFID usuallylack an optimized scheme of data collection and privacy

protection For example in the aspect of data collectionsome are operating in a single frequency band transmittingcollection-data via line even short of effective locationalgorithm and health data collection As we known thereare obvious disadvantages in wireline monitoring systemsuch as routing restriction the lack of flexibility and high-cost In terms of operation of frequency RFID systems canbe divided into four categories low frequency (LF) highfrequency (HF) ultra-frequency (UHF) and microwavewhich have different properties Due to low power strongpenetrating in RFID LF system moveable identification andmultitargets identification in other RFID systems how torealize the combination of the two advantages is a worthytopic [6ndash10] Findings indicated that healthy diet and suf-ficient and regular exercises not only contribute to reduceand resist chronic diseases but also promote physical andpsychological health of elderly people So to establish a systemthat can gather diet and exercise information and do some

HindawiJournal of Electrical and Computer EngineeringVolume 2017 Article ID 1360289 11 pageshttpsdoiorg10115520171360289

2 Journal of Electrical and Computer Engineering

statistical analysis for residents in nursing homes is of greatsignification Manual entry and a survey are applied fordata collection in traditional method which still have someproblems and drawbacks low-efficiency poor data qualityand less data quantity [11ndash14] In another aspect of privacyprotection security and privacy threats exist in the moni-toring system for nursing homes based on RFID in whichpersonal information recording information in daily lifeand personal property information are prone to attacks suchas replay attacks counterfeit attacks and tracking attacksIt is urgent to establish policies and standards for avoidingsecurity issues especially the encryption algorithm basedon Hash function Presently there are Hash-Lock protocolRandomized Hash-Lock protocol and Hash-Chain protocolHowever these have some flaws and fail to solve the securityproblems [15ndash20]

This paper adopts a RFID system with dual-band inwhich low frequency is used to activate the passive tag and theHF is used for communicating A simple algorithm namedvirtual routing location algorithm is introduced to realizearea location It effectively uses RFID and ZigBee technologyto establish an expandedRFIDwireless network for collectinglocation data Amethod of diet and exercise data acquirementbased on RFID technology is also proposed later At thesame time the system effectively integrates a lightweightRFID authentication protocol based on Hash function toachieve secure access and privacy protectionThis protocol iseffective against counterfeiting tracking and replay attacksand realizes the interaction between tag reader and back-end serverThese works show that the new system overcomesthe security leaks and has the merits of an optimized schemeof data collection low communication and computationcomplexity and so on

The rest of this paper can be outlined as follows Sec-tion 2 describes the architecture of the system along withmain modules which is divided into vertical and horizontalaspects functionmodule and security and privacy protectionmodule Section 3 discusses the key technology in thefunction module such as area location and data collectionbased on RFID Section 4 designs a kind of lightweight RFIDauthentication protocol based onHash function from the ver-tical aspect Section 5 sets up experimentation environmentand the network latency is tested along with related workFinally in Section 6 we summarize our discussion

2 System Description

The section mainly focuses on two aspects as follows onthe one hand the architecture of this system is proposedand the frequency selectivity of the RFID system workflowand communication mode are described in detail On theother hand the more detailed function requirements areanalyzed from vertical and horizontal aspects In the verticalaspect the system is divided into monitoring subsystem andservice subsystem Security and privacy are discussed fromthe horizontal aspect Security mode is embedded into everysubsystem such that a unified secure design makes sure thatthe monitoring system runs well

21 Architecture This system conforms to the IOT conceptwhich contains three layers the perceptual layer the networklayer and the application layer [3 7] The perceptual layer isat the most front-end of information collection and includeslocation nodes other data collection nodes sticking tags andRFIDwristbandsThen the information collected is uploadedto the back-end serve by ZigBee network with tree topologyin the network layer Finally the system uses NET+MYSQLtechnologies to realize the development of the whole systemincludingmonitoring subsystem service subsystem and webservice Its design architecture is shown in Figure 1

According to different requirements we choose two kindsof nodes for data collection Location node is designed tocollect the location information and the collection node isfor another data collection Each node communicates withCC2530 module by RS485 busThen ZigBee network formedby CC2530 modules will transmit the whole data to the back-end server

Every location node and RFID wristbands work togetherin two phases activation phase and communication phase125 KHz band is selected to activate passive part in a RFIDwristband and 433MHz band is for communication betweenone node and the active part of a wristband Comparedwith a single frequency band the Dual-band RFID systemcombines the advantage of low frequency and high frequencyeffectively low power and strong penetrating in LF systemmoveable identification andmultitargets identification inHFsystem According to the structure of antenna in a locationnode it can also be divided into single-channel mode anddual-channel mode which suit for different areas to belocated Every collection node mainly communicates withsticking tags which follows the EPC standards DesktopRFID reader with 433MHz frequency band is selected forcollection node to collect diet data part of exercise data andother service data

In the system tags or wristbands any one of RFIDreader and back-end service are connected with each otherby wireless network RFID or ZigBee This quite suits themonitoring system but it also brings a problemThe wirelesschannel is prone to attacks such as replay attack counterfeitattack and tracking attack So security and privacy should bepaid adequate attention

22 Function Module The monitoring system mainly con-tains monitoring subsystem and service subsystem accordingto the actual function from the vertical aspect Each subsys-tem combines with RFID wristbands to realize all-aroundautomatically monitoring management Security and privacyare designed to resist attacks from the horizontal aspect Thedetailed functions are shown in Figure 2

Monitoring subsystem offers a safe and secure environ-ment for the nursing homes residents All residents in thenursing homes wear RFID wristbands that can help the staffmonitor their locations So when dangers occur the staffcan quickly locate and provide appropriate help [5ndash7] Thespecific function is analyzed as follows

Journal of Electrical and Computer Engineering 3

Applicationlayer

Monitoring subsystem Service subsystem

Routing node

Real-time view

Gateway node

Web service

Back-end serve

ZigBee network

Networklayer

Indoor-exercise area

Securityand

privacyprotectionTerminal node

Diet area

Collection node

Sticking tag

Access and entrance area

Location nodePerceptual

layer Location node

wristbands

middot middot middot

Figure 1 The overall architecture

Health monitoring system for nursing homes with lightweight security and privacy protection

Resistance to trackingattack

Resistance tocounterfeit attack

Resistance to Mutual authenticationreplay attack

Service subsystemMonitoring subsystem

Area locationbased on RFID

Track record

Low-battery warning

Detention time

Diet data based onRFID

Exercise data based onREID

Other service data

Figure 2 Function diagram

(1) Area location this module is mainly used for locationQuery for the residents wearing RFID wristbands Oruse the module to achieve a certain period of timestatistics

(2) Low-battery warning the module can monitor theconsuming situation of battery for the RFID wrist-bands A warning signal is transmitted to the staffwhen the battery capacity is below the threshold


(3) Detection time calculate the detection time in somedangerous and privacy areas such as bathroomsand toilets For example a resident wearing a RFIDwristband stays in these areas longer than normal itis very likely that an emergency has happened

(4) Track record record the daily activities of the resi-dents wearing the RFID wristbands and then pro-vide the information for health assessment or otherrequirements

Service subsystem is designed to offer health serviceand others and collect diet and exercise data which partlyreflects the health of residents in the nursing homes Concreteanalysis is as follows

(1) Diet data based on RFID the diet data for everyresident in the nursing homes are collected by thecollection node tricking tags and RFID wristbandThe back-end serve will record the data and comparewith the standard

(2) Exercise data based on RFID the exercise data comesfrom three kinds of activities the usage of athleticfacilities the usage of indoor recreational area andoutdoor-activities All the exercise data and diet dataare supported to help professionals to access healthstatus for every resident in nursing homes

(3) Other service data the module is for other dataservices querying relational information for everyresident sending blessing on holiday reminding theresident to take medicine and so on

Security and privacy are designed to defend all thesubsystems from threats It can be detailed as follows

(1) Resistance to Counterfeit Attacks It prevents attackersfrom counterfeit RFID tags or readers illegal access topersonal information of the resident guardian informationand sensitive data and so on

(2) Resistance to Tracking Attacks It prevents attackers fromgaining traces of activity by tracking location informationthreatening their person and property

(3) Resistance to Replay Attacks In an extreme case theattacker may obtain relevant information It prevents it frombeing reproduced by using this information thereby illegallypassing the authentication

(4) Mutual Authentication It aims to achieve the tag readerand the back-end server mutual authentication between thethree

Security design will be embedded above the varioussubfunctional modules and unified security design to ensurethat all functional modules are safe The next step will be adetailed analysis of key technologies and the authenticationprotocol in the security module

3 Key Technologies

As mentioned the system is divided into monitoring sub-system and service subsystem from the vertical aspect Thearea location module is very important and supports theother modules And that diet data and exercise data are theimportant parts of service subsystem So in this section wewill focus on the key technologies on these modules arealocation diet data and exercise data collection

31 Area Location Based on RFID According to the structurecharacteristics of the monitoring area in nursing homes itcan be divided into different areas such as indoor gym-nasium area diet area indoor-recreation area and accessand entrance area The system is designed to provide amore flexible easily configurable deployment model So wecan deploy the location node according to actual size ofareas to be monitored and other requirements The actualphysical location is known when the location node has beendeployed In this section we will talk about the process of dataacquisition of one location node and the location algorithm

The location nodes mainly work together with RFIDwristbands then the workflow of one single location nodeand RFID wristband is shown in Figure 3

The process of data acquisition consists of two phasesnamely activate phase and communication phase In thetrigger phase the location node sets control parameters andinitiates readers at first Then the RFID reader (locationnode) will scan RFID tags (RFID wristbands) in its coveragearea Finally when the searched tag ID matches the IDstored in memory the communication can begin In thecommunication phase the RFID reader starts to receive dataafter authenticating successfully If the data is a distress signalor warning signal then give priority to transmit otherwisetransmit the location data in the order queue

The location data mainly contains location array whichcomes from the virtual routing location algorithm In thefollowing parts we will simply describe the basic conceptsabout the algorithm The algorithm uses ZigBee and RFIDtechnology to form the RFID wireless network the coverageis far away As we known the read-write distance of RFIDreader is relatively close So we assume that the tag to belocated has the same physical location with the RFID readerAs the resident wearing RFID wristband moves in the RFIDwireless network the wristband will transmit a location arrayto back-end server The principle of the algorithm is shownin Figure 4

Assuming that the coordinates of all readers are alreadyknown then the coordinate of the tag can be gotten by thealgorithm As shown in Figure 4 the solid line is the actualroute the tag selected and the dotted line is the virtual routewhich is calculated by the algorithm For example the actualroute of the tag can be the same as the virtual route as shownbelow

(0 0) 997888rarr (1 1) 997888rarr (1 2) 997888rarr (1 3) 997888rarr (1 4) 997888rarr (2 4) 997888rarr (3 3) 997888rarr (4 2) 997888rarr (3 1) 997888rarr (3 0) (1)


Clearthe ID

Start

Set control parameter

Scan coverage area RFID tags

The tag isdetected

The tag ID =

a tag ID in buffer

Activate the tag ready tocommunicate with the

reader

No

No

YesYes

Yes

Yes

YesNo

No

Nocertificate

Start to receive data

Distress signal

Data (tag ID triggernode ID trigger time)

Queue order transmit

Give priority totransmissions

Clear thedata

433MHz security

Figure 3 Workflow for one location node

ReaderTag

Actual routeVirtual route

1

10

2

2

3

3

4

4

Figure 4 Schematic diagram of the algorithm

A location array is chosen to realize the progress of thealgorithm It contains three parameters the ID of the tag thereading time and the ID of the readerThe following formulacan be used⟨119879119894 119905119895 119877119896⟩ = ⟨tag 119895 time 119895 reader 119896⟩ (2)

As shown is formula (2) the location array is expressedby ⟨119879119894 119905119895 119877119896⟩ 119879119894 is the ID of the 119894th tag 119877119896 is the ID of the119896th reader And 119905119895 is the time when the 119896th RFID readerstarts to communicate with the 119894th tag Location arrays arefirstly categorized according to 119879119894 and then according to 119905119895Finally we can get the coordinate of 119896th RFID reader as thecoordinate of 119894th tag at the time of 119905119895 The algorithm is simpleand effective fully in line with the needs of area location forthe nursing homes

32 Health Data Based on RFID In this section we will buildamodule to collect diet and exercise data automatically basedon RFID and do some statistical analysis Diet and exercisedata is usually very complex but there still has certainregularity and periodicity for collective life environmentin nursing homes Based on this application backgrounda simplified model for diet and exercise data collection isdesigned as follows

Diet area is divided into selection-area and settlement-area In selection-area plates and bowls sticking with tagsestablish the one-to-one relationship between each tag andthe food in its plate or bowl The settlement-area mainlycontains RFID readers and displays With the help of stickingtags RFID readers and wristbands the subsystem can realizesettlement and diet data collection quickly and automaticallyNext we will introduce the progress of data analysis in the


Table 1 Exercise data based on RFID

Categories Indoor-entertainment Outdoor-activities Athletic facilities

MethodsAccumulate the continuous

time by indoor-RFIDreaders

Accumulate the continuoustime by entrance-RFID

readers

Accumulate the exercisetime on athletic facilities by

RFID readersTime (hoursday) 1198791 1198792 1198793The weight 1199081 1199082 1199083back-end server Five categories of the essential nutrients inbody are chosen as the main parameters to analyze whichare proteins fats carbohydrates and trace elements vitaminsand minerals Based on a nutrient criterion proposed byChina and the special requirements for the elderly a dailymeal nutrition supplement standards are designed Com-pared with the standards the system will judge whetherthe daily diet is reasonable and then put forward somesuggestions Finally a mathematical model is built to detailthe progress Let the amount of common food in nursinghomes as 119894 119896 take 1 to 5 respectively as protein fat vitaminsenergy minerals and inorganic salts 119886119896119894 is the value of 119896thnutrient in 119894th food and 119886119894119896 isin 119860 119906119894119896 is the value of dailyintake of 119896th nutrient in 119894th food and 119906119894119896 isin 119861 119906119894119896 = 1the formula indicates that the 119896th nutrient contained in the119894th food is ingested The daily intake of nutrients is shown informula (3)

119884 = 119860 lowast 119880 = (11988611 sdot sdot sdot 1198861119894 d1198861198961 sdot sdot sdot 119886119896119894)(11990611 sdot sdot sdot 1199061119896 d

1199061198941 sdot sdot sdot 119906119894119896)= (11991011 sdot sdot sdot 1199101119894 d

1199101198961 sdot sdot sdot 119910119896119894)(3)

119884 is the daily intake of nutrients 119910119896119894 express the 119896thnutrient intake from the 119894th food Add the elements in thesame column for array 119884 and get a new array 119881 = (V1 V2 V119896) V119896 is the 119896th nutrient you has been absorbed119872 = (1198981 1198982 119898119896) is the standard value of nutrientsComparing the 119881 with 119872 a result that whether you get thesufficient nutrients or not will be offered to the residents andstaff

The system classifies exercises as indoor-entertainmentoutdoor-activities and exercise on athletic facilities Formula(4) as below is used to calculate the amount of exercises dailysimplify

119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)

As shown in formula (4) 119899 = 3 119894 = 1 2 3 representindoor-entertainment outdoor-activities and exercise onathletic facilities respectively 119908119894 is the weight value of theamount of the whole exercises The sum amount of 119894th

③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag

① Reader Tag Query rR

③ Reader DataBase Query④ DataBase Reader rD

② Tag DataBase M1M2

⑥ DataBase Reader M㰀3M

㰀4

⑦ Reader Tag M㰀3

⑤ Reader DataBase M2M3M4 rT

M3 rT

rR

Figure 5 The authentication flow of the protocol

exercises daily is 119879119894 and the sum of all kinds of exercise iscalculated by formula (4) noted by 119878The specific progress ofcalculation is shown in Table 1

According to the health status of the elderly and specialneeds daily exercise standards are designed when the elderlychecked in the nursing home And the standard for com-parison to determine the amount of the daily exercise isappropriate or not

4 Security and Privacy

As before security and privacy are very important for thewireless system and security mode is embedded into everysubsystem So a mobile authentication protocol based onHash function is designed in this section The procedure andimplementation of the protocol are discussed as follows

41 Proposed Protocol Based on a one-way Hash functionthis paper proposed a mutual authentication for informationprotection It is depicted in Figure 5 The symbols in theprotocol are described as follows 119867(119909) is the Hash functionof 119909 ID119879 is the identification number of the tag and is storedin the tag ID119877 is the identification number of the RFID readerand is stored in the reader (ID1015840119877 119867(ID1015840119877)) and (ID1015840119879 119867(ID1015840119879))are stored in the DataBase The authentication flow of theprotocol is shown in Figure 5

(1) The RFID reader generates a random number 119903119877 andsends (Query 119903119877) to the tag


Table 2 Protocol performance analysis

Performance actor Hash-Lock Radom Hash-Lock Hash-Chain The proposed protocolComputational complexity

Tag 1119867 1119867 + 1119877 2119867 3119867 + 1119877Reader mdash (sum(1198992))119867 mdash 4119867 + 1119877DataBase mdash mdash (sum(1198992))119867 4119867 + 1119877

Security performanceResistance to counterfeiting attacks times times times Resistance to tracking attacks times times Resistance to replay attacks times times times Two-way authentication times times (2) The tag receives the data generates a random number119903119879 and then uses the received number and calculates1198721 = 119867(119903119877 119903119879) 1198722 = 119867(ID119879) oplus 1198721 and 1198723 =119867(ID119879 119903119877 119903119879)1198723 is stored in the tag and (119872111987221198723 119903119879) are sent to the reader(3) Using the received random number 119903119879 and its gener-

ated random number 119903119877 the reader calculates 11987210158401 =119867(119903119877 119903119879) Then it makes a judge whether 11987210158401 isequal to the received variable 1198721 if 11987210158401 = 1198721 thetag is authenticated And then Query is sent to theDataBase

(4) After receiving the Query the DataBase generates arandom number 119903119863 and sends it to the reader

(5) Using the received 119903119863 and its own numbers 119903119877 andID119877 the reader calculates the following numbers1198724 = 119867(ID119877) oplus 119867(119903119877 119903119863) and 1198725 = 119867(ID119877 119903119877 119903119863) 1198725 is stored in the reader and (119872211987231198724 119903119879 119903119877) are sent to the DataBase

(6) When the DataBase receives the data it will carryon the following three steps The first step is toauthenticate the reader it calculates11986710158401015840(ID119877) = 1198724oplus119867(119903119877 119903119863) tomeet the requirement of (ID1015840119877 119867(ID1015840119877))which are stored in the DataBase And if 11986710158401015840(ID119877) =119867(ID1015840119877) the reader is authenticated In the secondstep it calculates 11986710158401015840(ID119879) = 1198722 oplus 119867(119903119877 119903119879) If11986710158401015840(ID119879) = 119867(ID1015840119879) the tag is authenticated Thethird step calculates 11987210158405 = 119867(ID1015840119877 119903119863 119903119877) and11987210158403 = 119867(ID1015840119879 119903119879 119903119877) and sends (1198721015840311987210158405) to thereader

(7) The reader compares the received data 11987210158405 with thedata 1198725 which is stored earlier If 11987210158405 = 1198725 thenthe reader authenticates the DataBase and sends 11987210158403to the tag

(8) The tag receives the data 11987210158403 and compares it to thedata 1198723 which is stored in tag earlier If 11987210158403 = 1198723then the tag authenticates both the Reader and theDataBase

42 Protocol Performance Analysis The following will ana-lyze security performances of the proposed protocol fromfour aspects

(1) Resistance to Counterfeiting Attacks The protocol caneffectively exploit the one-way of Hash function The attack-ers cannot analyze the identification numbers of the tag orthe reader by intercepting data So the system has the abilityto resist counterfeiting attacks

(2) Resistance to Tracking Attacks The tag the reader and theDataBase will generate random numbers the response dataare changing in each certification process So attackers areunable to obtain location information thus avoiding trackingattacks

(3) Resistance to Replay Attacks The random numbers of thetag the reader and the DataBase are changed during eachauthentication process so that the previous authenticationinformation cannot be used to complete the replay attacks

(4) Two-Way Authentication Firstly the reader authenticatesthe tag by judging whether 11987210158401 = 1198721 Then the DateBaseverifies the security of the tag and the reader by the received(119872211987231198724 119903119879 119903119877) Finally the reader authenticates theDataBase by the formula11987210158405 = 1198725 And the tag verifies thatthe formula 11987210158403 = 1198723 is true and authenticates the Readerand the DataBase

On the basis of security considerations the protocolproposed also effectively reduces the calculation of the tagreducing tag costs and the use of energy consumption asshown in Table 2 In Table 2 119867 is the Hash function 119877 isthe random function 119899 is the total number of tags and ldquomdashrdquois not Hash function random function and so on [18ndash20]

As shown in Table 2 this authentication protocol fullyconsiders the newproblems brought by thewireless transmis-sion of the mobile RFID system compared with the classicalprotocol The proposed protocol balances the computationalprotocol at the tag the reader and the DataBase whileproviding strong security which can resist various types ofattacks obtain dual-authentication and decrease computa-tional complexity All these performancesmake the proposedthe system be appropriate for the nursing homes usage

5 Performance Testing and Related Work

The following will analyze the performance and related workto verify the feasibility and superiority of the system Firstly


Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206

Figure 6 Location nodes layout diagram

we will build the test environment testing the systemrsquos net-work delay characteristics and then analyze the related workof the system and compare it with the common monitoringsystem

51 Performance Testing Because the indoor layout of thenursing home is similar to the laboratory we choose thesecond floor laboratory to carry out system testing Themonitoring rooms are divided into 201 room 202 room 203room 204 room 205 room 206 room the lobby and serverroom as shown in Figure 6

As shown in Figure 6 the RFID node 1 and node 2 arelocated in the lobby area The node 3 is arranged at theentrance of the room 201 Moreover node 4 is located at the203 entrance of the room 203 node 5 at the room 205 node8 at the room 206 node 7 at the room 204 and node 6 atthe room 202 The coordinate node is arranged at the serverroom and connected with the back-end server The distancebetween the location nodes is 6ndash8 meters and the nodes thatare far away from the server communicate with their nearestnodes as the parent nodeWe use packet sniffer and hardwaretimers to test the system Assume that the data acquisitioninterval is 5 s and 100 times for each node during the testTheaverage network delay for each node is shown in Figure 7

From Figure 7 we can see that the network latency ofnodes 1 2 3 and 6 is close to each other In the networktopology these nodes are single-hop nodes and the actualphysical location is closer to the coordinator node Node 4and node 7 are close to each other In the network topologythey are two-hop nodes Node 5 and node 8 are three-hopnodes and the network delay is relatively large Thereforethe system topology design has some impact on the networkdelay but overall adding a security authentication protocolincreases the systemrsquos average network latency [19 20] andthe simulation show that the implementation of the protocol

Average network delay of each node

Node

No protocolThis paper

0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)

Figure 7 The average network delay of each node

time is about 500ndash550ms but manymonitoring systems dataacquisition time is about 5ndash60 s So here 5 s is chosen as thesampling interval we discuss the relative network latency andthe average network delay divided by the sampling intervalas shown in Figure 8

Figure 8 shows that comparedwith the sampling intervalthe relative network delay for the proposed system withlightweight security and privacy protocol is less than 35 sothe authentication protocol does not affect the system real-time data collection but can greatly improve system securityand privacy


Table 3 Week of diet data from a tester

Dataappliance Week of diet data from a testerProtein (g) Fat (g) Vitamins (mg) Minerals and inorganic salts (mg) Energy (KJ)

02102016 (Sun) 731 237 8132 5828 6307503102016 (Mon) 761 455 13075 627333 69538104102106 (Tue) 952 603 863 783285 72006705102016 (Wed) 1075 718 8408 740973 97905606102016 (Thu) 871 45 8935 689935 72843407102016 (Fri) 928 637 11355 754183 80374608102016 (Sat) 661 296 4636 52829 551451Mean 8541 4851 9024 6724 72984Reference value 65sim75 25 1305sim1314 6530 7100sim9200Conclusion High High Low High Normal

Table 4 Week of exercise data from a tester

Dataappliance

Week of exercise data from a testerIndoor-

entertainment(1199081 = 02) Outdoor-activities

(1199082 = 035) Athletic facilities(1199083 = 045) Sum (hour) Reference value

(hour)

02102016 (Sun) 2 hours 05 hour 03 hour 071

06sim103102016 (Mon) 3 hours 08 hour 02 hour 09704102106 (Tue) 25 hours 1 hour 02 hour 09405102016 (Wed) 4 hours 01 hour 0 hours 083506102016 (Thu) 36 hours 03 hour 03 hour 09607102016 (Fri) 28 hours 04 hour 01 hour 074508102016 (Sat) 36 hours 03 hour 03 hour 096

Relative network delay


02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node

Figure 8 Relative network delay

In the experimental environment we collected a week ofdiet and exercise data from a tester as shown in Tables 3 and4

In Table 3 the reference value comes from daily intake ofdietary nutrient values for Chinese residents aged 60 yearsand over The nursing home provides a basic diet menusimilar to the one provided each week which facilitates thecollection of diet data In Table 4 the reference value can beadjusted according to the previous exercise and health statusWe can see that week of diet and exercise data have certainregularity and periodicity to reflect the elderlyrsquos diet andexercise status which can monitor the health of the elderly

52 Related Work There are a lot of monitoring systemsbut few ones are in line with the needs of nursing homes inall aspects Reference [21] introduces a remote monitoringsystem for the tower clusters which focuses on industrial datatransmission and is not suitable for the elderlymonitoring In[22] a remote monitoring system based on intelligent fiberstructure is proposedThe system uses the liquid core opticalfiber structure based on ARM and GPRS to communicateThe cost is high and cannot be applied to the nursing homemonitoring system References [23 25] all use video fordata acquisition Reference [23] uses the pyroelectric infraredsensor and the video monitor to carry on the multitargettracking But its calculation and communication complexityare high and the data acquisition is not comprehensiveIn [24] a wireless network life-monitoring system for thenursing home is proposed which uses the wireless sensor


Table 5 Comparison of related system performance

Monitoringsystems

System performanceSuitable for

nursing homesMain technicalshortcomingsReal-time Data

comprehensivenessSecurity and

privacy

Computationaland

communicationcosts

Reference [21] Medium Industrial data Low medium No Lack of security

Reference [22] Medium Industrial data Low High NoCommunicationcosts are highLack of security

Reference [23] High Location data Medium High YesComputationalcosts are highData are not

comprehensive

Reference [24] Medium Health data Low Low Yes Data are notcomprehensive

The systemproposed High Comprehensive data High Low Yes No

network to collect the basic health data but lacks the consid-eration of security and privacy protection Specific analysisand comparison are shown in Table 5

Compared with the monitoring system shown in Table 5the system has four characteristics high real-time moni-toring small network delay comprehensive data collectioninvolving location information diet and exercise data collec-tion security and privacy protection mechanism embeddedin the module design the use of lightweight mobile securityarchitecture computing and low communication cost

6 Conclusion

According to the characteristics and needs of the nursinghome this paper designed a health monitoring system withlightweight security and privacy protection which is focusedon vertical and horizontal aspects health data collection andsecurity and privacy protection From the vertical aspectRFID dual-frequency band virtual route location algorithmand diet and exercise data acquisition based on RFID areadopted in the health data collection From the horizontalaspect a lightweight RFID authentication protocol based onHash function is embedded into each collection modulewhich has high security and low computation cost Throughthe performance analysis and testing we can see that thesystem has characteristics of high security high real-timeand high data comprehensive and low computational andcommunication complexity and fully meets the needs ofhealth monitoring system for the nursing homes

Competing Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

This work was supported in part by Educational Commissionof Anhui Province under Grant 2015jyxm237 and in partby the Foundation of University Research and InnovationPlatform Team for Intelligent Perception and Computing ofAnhui Province

References

[1] M H Y Shum V W Q Lou K Z J He C C H Chen andJ Wang ldquoThe lsquoLeap Forwardrsquo in nursing home development inUrban China future policy directionsrdquo Journal of the AmericanMedical Directors Association vol 16 no 9 pp 784ndash789 2015

[2] N Kumar K Kaur S C Misra and R Iqbal ldquoAn intelligentRFID-enabled authentication scheme for healthcare applica-tions in vehicular mobile cloudrdquo Peer-to-Peer Networking andApplications vol 9 no 5 pp 824ndash840 2016

[3] N K Suryadevara and S C Mukhopadhyay ldquoWireless sensornetwork based home monitoring system for wellness determi-nation of elderlyrdquo IEEE Sensors Journal vol 12 no 6 pp 1965ndash1972 2012

[4] J E Morley G Caplan M Cesari et al ldquoInternational surveyof nursing home research prioritiesrdquo Journal of the AmericanMedical Directors Association vol 15 no 5 pp 309ndash312 2014

[5] J E Morley ldquoUnder nutrition a major problem in nursinghomesrdquo Synthetic Communications vol 44 no 8 pp 1019ndash10422014

[6] H Makimura K Watanabe H Igarashi and H Waki ldquoMoni-toring system of railway using passive RFID inUHF bandrdquo IEEJTransactions on Electronics Information and Systems vol 132no 5 pp 691ndash696 2012

[7] L M Wang and S M Xiong Introduction to the Internet ofThings Engineering Tsinghua University Press Beijing China2011


[8] J C Chen and T J Collins ldquoCreation of a RFID based real timetracking (R-RTT) system for small healthcare clinicsrdquo Journalof Medical Systems vol 36 no 6 pp 3851ndash3860 2012

[9] N Li and B Becerik-Gerber ldquoPerformance-based evaluationof RFID-based indoor location sensing solutions for the builtenvironmentrdquo Advanced Engineering Informatics vol 25 no 3pp 535ndash546 2011

[10] K Liu and Z C Ji ldquoResearch on RFID reader network trackingalgorithmrdquo Computer Engineering vol 38 no 18 pp 248ndash2502012

[11] M Arebey M A Hannan H Basri R A Begum and HAbdullah ldquoSolid waste monitoring system integration basedon RFID GPS and camerardquo in Proceedings of the InternationalConference on Intelligent and Advanced Systems (ICIAS rsquo10) pp1ndash5 June 2010

[12] Y Tao X Zhou Y Ma and F Zhao ldquoMobile mutual authenti-cation protocol based on hash functionrdquo Journal of ComputerApplications vol 36 no 3 pp 657ndash660 2016

[13] S-J Zhou W-Q Zhang and J-Q Luo ldquoSurvey of privacy ofradio frequency identification technologyrdquo Journal of Softwarevol 26 no 4 pp 960ndash976 2015

[14] A Wickramasinghe D C Ranasinghe C Fumeaux K D Hilland R Visvanathan ldquoSequence learning with passive RFIDsensors for real time bed-egress recognition in older peoplerdquoIEEE Journal of Biomedical and Health Informatics p 1 2016

[15] B Fabian T Ermakova and C Muller ldquoSHARDIS a privacy-enhanced discovery service for RFID-based product informa-tionrdquo IEEE Transactions on Industrial Informatics vol 8 no 3pp 707ndash718 2012

[16] X L Liu H Qi Q K Li et al ldquoEfficient detection ofcloned attacks for large-scale RFID systemsrdquo in Algorithms andArchitectures for Parallel Processing vol 8630 of Lecture Notes inComputer Science pp 85ndash99 Springer International PublishingBerlin Germany 2014

[17] A Arbit Y Oren and A Wool ldquoA secure supply-chain RFIDsystem that respects your privacyrdquo IEEE Pervasive Computingvol 13 no 2 pp 52ndash60 2014

[18] H Jannati and B Bahrak ldquoSecurity analysis of an RFID tagsearch protocolrdquo Information Processing Letters vol 116 no 10pp 618ndash622 2016

[19] X YWang F X Jing andYQWang ldquoAn improved hash-basedRFID security authentication algorithmrdquo Journal of ShangdongUniversity vol 49 no 9 pp 154ndash159 2014

[20] D-Z Sun and J-D Zhong ldquoA hash-based RFID securityprotocol for strong privacy protectionrdquo IEEE Transactions onConsumer Electronics vol 58 no 4 pp 1246ndash1252 2012

[21] H M Zheng Y J Wang K Chen and J T Zhang ldquoDesignof wireless remote security monitoring system for tower cranefleetrdquo Journal of Electronic Measurement and Instrumentationvol 28 no 5 pp 520ndash527 2014

[22] L Shen Z Zhao and X Yu ldquoDesign of remote monitoringinternet of things system for new optical fiber smart structurerdquoJournal of Nanjing University of Aeronautics and Astronauticsvol 3 no 47 pp 453ndash458 2015

[23] F-M Li N Jiang J Xiong and J-Y Zhang ldquoMulti-objecttracking scheme with pyroelectric infrared sensor and videocamera coordinationrdquo Acta Electronica Sinica vol 42 no 4 pp672ndash678 2014

[24] Y-J Chang C-H Chen L-F Lin R-P Han W-T Huang andG-C Lee ldquoWireless sensor networks for vital signsmonitoring

application in a nursing homerdquo International Journal of Dis-tributed Sensor Networks vol 2012 Article ID 685107 12 pages2012

[25] G-X Han and C-R Li ldquoImprovement on moving objecttracking method for network video surveillancerdquo Journal onCommunications vol 35 pp 160ndash164 2014

International Journal of

AerospaceEngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

RoboticsJournal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Active and Passive Electronic Components

Control Scienceand Engineering

Journal of



RotatingMachinery


Hindawi Publishing Corporation httpwwwhindawicom

Journal ofEngineeringVolume 2014

Submit your manuscripts athttpswwwhindawicom

VLSI Design



Shock and Vibration


Civil EngineeringAdvances in

Acoustics and VibrationAdvances in



Electrical and Computer Engineering

Journal of

Advances inOptoElectronics


Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014

SensorsJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



statistical analysis for residents in nursing homes is of greatsignification Manual entry and a survey are applied fordata collection in traditional method which still have someproblems and drawbacks low-efficiency poor data qualityand less data quantity [11ndash14] In another aspect of privacyprotection security and privacy threats exist in the moni-toring system for nursing homes based on RFID in whichpersonal information recording information in daily lifeand personal property information are prone to attacks suchas replay attacks counterfeit attacks and tracking attacksIt is urgent to establish policies and standards for avoidingsecurity issues especially the encryption algorithm basedon Hash function Presently there are Hash-Lock protocolRandomized Hash-Lock protocol and Hash-Chain protocolHowever these have some flaws and fail to solve the securityproblems [15ndash20]

This paper adopts a RFID system with dual-band inwhich low frequency is used to activate the passive tag and theHF is used for communicating A simple algorithm namedvirtual routing location algorithm is introduced to realizearea location It effectively uses RFID and ZigBee technologyto establish an expandedRFIDwireless network for collectinglocation data Amethod of diet and exercise data acquirementbased on RFID technology is also proposed later At thesame time the system effectively integrates a lightweightRFID authentication protocol based on Hash function toachieve secure access and privacy protectionThis protocol iseffective against counterfeiting tracking and replay attacksand realizes the interaction between tag reader and back-end serverThese works show that the new system overcomesthe security leaks and has the merits of an optimized schemeof data collection low communication and computationcomplexity and so on

The rest of this paper can be outlined as follows Sec-tion 2 describes the architecture of the system along withmain modules which is divided into vertical and horizontalaspects functionmodule and security and privacy protectionmodule Section 3 discusses the key technology in thefunction module such as area location and data collectionbased on RFID Section 4 designs a kind of lightweight RFIDauthentication protocol based onHash function from the ver-tical aspect Section 5 sets up experimentation environmentand the network latency is tested along with related workFinally in Section 6 we summarize our discussion

2 System Description

The section mainly focuses on two aspects as follows onthe one hand the architecture of this system is proposedand the frequency selectivity of the RFID system workflowand communication mode are described in detail On theother hand the more detailed function requirements areanalyzed from vertical and horizontal aspects In the verticalaspect the system is divided into monitoring subsystem andservice subsystem Security and privacy are discussed fromthe horizontal aspect Security mode is embedded into everysubsystem such that a unified secure design makes sure thatthe monitoring system runs well

21 Architecture This system conforms to the IOT conceptwhich contains three layers the perceptual layer the networklayer and the application layer [3 7] The perceptual layer isat the most front-end of information collection and includeslocation nodes other data collection nodes sticking tags andRFIDwristbandsThen the information collected is uploadedto the back-end serve by ZigBee network with tree topologyin the network layer Finally the system uses NET+MYSQLtechnologies to realize the development of the whole systemincludingmonitoring subsystem service subsystem and webservice Its design architecture is shown in Figure 1

According to different requirements we choose two kindsof nodes for data collection Location node is designed tocollect the location information and the collection node isfor another data collection Each node communicates withCC2530 module by RS485 busThen ZigBee network formedby CC2530 modules will transmit the whole data to the back-end server

Every location node and RFID wristbands work togetherin two phases activation phase and communication phase125 KHz band is selected to activate passive part in a RFIDwristband and 433MHz band is for communication betweenone node and the active part of a wristband Comparedwith a single frequency band the Dual-band RFID systemcombines the advantage of low frequency and high frequencyeffectively low power and strong penetrating in LF systemmoveable identification andmultitargets identification inHFsystem According to the structure of antenna in a locationnode it can also be divided into single-channel mode anddual-channel mode which suit for different areas to belocated Every collection node mainly communicates withsticking tags which follows the EPC standards DesktopRFID reader with 433MHz frequency band is selected forcollection node to collect diet data part of exercise data andother service data

In the system tags or wristbands any one of RFIDreader and back-end service are connected with each otherby wireless network RFID or ZigBee This quite suits themonitoring system but it also brings a problemThe wirelesschannel is prone to attacks such as replay attack counterfeitattack and tracking attack So security and privacy should bepaid adequate attention

22 Function Module The monitoring system mainly con-tains monitoring subsystem and service subsystem accordingto the actual function from the vertical aspect Each subsys-tem combines with RFID wristbands to realize all-aroundautomatically monitoring management Security and privacyare designed to resist attacks from the horizontal aspect Thedetailed functions are shown in Figure 2

Monitoring subsystem offers a safe and secure environ-ment for the nursing homes residents All residents in thenursing homes wear RFID wristbands that can help the staffmonitor their locations So when dangers occur the staffcan quickly locate and provide appropriate help [5ndash7] Thespecific function is analyzed as follows


Applicationlayer


Routing node

Real-time view

Gateway node

Web service

Back-end serve

ZigBee network

Networklayer


Securityand


Diet area

Collection node

Sticking tag



layer Location node

wristbands









Track record

Low-battery warning

Detention time



Other service data

















3 Key Technologies









Clearthe ID

Start



The tag isdetected

The tag ID =

a tag ID in buffer


reader

No

No

YesYes

Yes

Yes

YesNo

No

Nocertificate


Distress signal




Clear thedata

433MHz security


ReaderTag


1

10

2

2

3

3

4

4












readers





1199101198961 sdot sdot sdot 119910119896119894)(3)



119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)


③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag





㰀4



M3 rT

rR





























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Applicationlayer


Routing node

Real-time view

Gateway node

Web service

Back-end serve

ZigBee network

Networklayer


Securityand


Diet area

Collection node

Sticking tag



layer Location node

wristbands









Track record

Low-battery warning

Detention time



Other service data

















3 Key Technologies









Clearthe ID

Start



The tag isdetected

The tag ID =

a tag ID in buffer


reader

No

No

YesYes

Yes

Yes

YesNo

No

Nocertificate


Distress signal




Clear thedata

433MHz security


ReaderTag


1

10

2

2

3

3

4

4












readers





1199101198961 sdot sdot sdot 119910119896119894)(3)



119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)


③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag





㰀4



M3 rT

rR





























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation






















3 Key Technologies









Clearthe ID

Start



The tag isdetected

The tag ID =

a tag ID in buffer


reader

No

No

YesYes

Yes

Yes

YesNo

No

Nocertificate


Distress signal




Clear thedata

433MHz security


ReaderTag


1

10

2

2

3

3

4

4












readers





1199101198961 sdot sdot sdot 119910119896119894)(3)



119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)


③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag





㰀4



M3 rT

rR





























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










Clearthe ID

Start



The tag isdetected

The tag ID =

a tag ID in buffer


reader

No

No

YesYes

Yes

Yes

YesNo

No

Nocertificate


Distress signal




Clear thedata

433MHz security


ReaderTag


1

10

2

2

3

3

4

4












readers





1199101198961 sdot sdot sdot 119910119896119894)(3)



119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)


③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag





㰀4



M3 rT

rR





























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation















readers





1199101198961 sdot sdot sdot 119910119896119894)(3)



119878 = 119899sum119894=1

(119879119894 lowast 119908119894) (4)


③

②

①

④

⑤

⑥

⑦

DataBase(ID㰀

T H(ID㰀T))

(ID㰀R H(ID㰀

R))

Reader

(IDR) (IDT)Tag





㰀4



M3 rT

rR





























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation






























Node 1

Coordinate

Node 2

Node 3

Node 4

Node 5

Node 6

Node 7

Node 8

204

202201

203

205

206







Node


0 1 2 3 4 5 6 7 80

02

04

06

08

1

12

14

16

18

2

Aver

age n

etw

ork

delay

(s)









Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation














Dataappliance




(hour)





02

0 2 3 4 5 6 7 8 910

005

01

015

025

03

035

04

Aver

age n

etw

ork

delay

sam

plin

g in

terv

al (

)

Node







Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











Monitoringsystems




privacy

Computationaland

communicationcosts




comprehensive





6 Conclusion


Competing Interests


Acknowledgments


References






























RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation































RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Health Monitoring System for Nursing Homes with...

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