2013 IEEE GCC Conference and exhibition, November 17-20, Doha, Qatar An Interoperable Multi-Sensor System For Healthcare Bassant Selim Youssef Iraqi Ho-Jin Choi Khalifa University Khalifa University KAIST Sharjah, United Arab Emirates Sharjah, United Arab Emirates Daejeon, South Korea Email: [email protected] Email: [email protected] Email: [email protected] Abstract—Pervasive healthcare systems, enabled by informa- an introduction to the sensor standards considered, section tion and communication technology (ICT), can allow the elderly IV presents the requirements and solutions that insure the and chronically ill to stay at home while being constantly adequate performance of our system, section V provides an monitored. Patient monitoring can be achieved by sensors and example of sensor Modeling Language description of a body sensor systems that are both worn by the patient and installed temperature sensor, section VI presents related works in the in his home environment. There is a large variety of sensors area of applying standards to healthcare monitoring systems available on the market that can all serve to this purpose. In order to have a system that is independent of the sensors that and finally section VII concludes this work. are used, standardization is the key requirement. This work aims to present a framework for healthcare monitoring systems based II. SYSTEM ARCHITECTURE on heterogeneous sensors. In order to achieve interoperability, standards are considered in the system design. The proposed system is composed of multiple hierarchical layers that are each responsible of monitoring different pa- Keywords—Heterogeneous Sensor Networks, SensorML, IEEE rameters of the patient’s health. Each layer is able to query 1451, Healthcare monitoring information from the layer under it. Layer 1 is the Sensor Processing Units (SPUs) which deal with specific sensors I. INTRODUCTION details and provide a uniform interface to higher layers. In this layer, the physiological data extracted by the sensors is The development of medical technologies has led the world processed, stored, and forwarded to the higher level when to face the burden of healthcare provisioning to the elder needed. The SPUs report and are under the control of Low population that is constantly growing. Advances in Information Level Processing Units (LLPUs). and Communication Technology have provided many solutions for healthcare monitoring. In fact, a considerable amount of The second layer is made of Low Level Processing Units healthcare monitoring systems and devices are available on the (LLPUs) that have a relatively higher view of the situation. market. These devices are constantly evolving to become less This layer gathers data from the SPUs, combines them, and invasive and power consuming. Designing a healthcare system detects abnormal behavior and critical situations based on the that is tied up with fixed devices would not allow it to benefit patient’s condition. Each LLPU is equipped with a database from technological advances in these devices. Interoperability, where the information related to the patient’s condition is which is the ability to work with any set of sensors, should stored. The LLPUs perform more advanced functions like be considered as a key requirement by pervasive healthcare filtering, correlation, and intelligent processing of data and monitoring systems. take proper actions. These actions include sending a reminder to the user, placing an emergency call or even turning on the Providing a standard sensor interface can allow the connec- air conditioner. An LLPU will not only receive data from the tion of any sensor to the network. The IEEE 1451 family of SPUs, but it can also ask the SPUs to perform certain actions standards defines a set of open, common, network-independent (e.g. changing the frequency of data acquisition). communication interfaces for connecting transducers (sensors or actuators) to microprocessors, instrumentation systems, and The LLPUs are also responsible of forwarding data to the control/field networks [1]. In addition, a formal sensor descrip- highest level which is the High Level Processing Unit (HLPU). tion can provide the system with additional information about This level is responsible of performing further operations on the sensor’s characteristics and capabilities. This information the data. The HLPU handles a complex database containing is useful for the efficiency of the system, allowing tasking the historical data of a large number of patients and is able of sensors and reconfiguration of sensor parameters. This to process this information to detect early symptoms of new formal description can be provided by the Open Geospatial conditions observed in a patient’s historical data. If there are Consortium’s Sensor Web Enablement Standards, particularly any suspicions about the user’s heath the HLPU is also capable the Sensor Modeling Language standard. A combination of of placing alerts to the caregivers. The architecture described these two standards enables plug and play mode of any sensor above can be deployed in individuals’ homes as well as in to the network, achieving the desired interoperability. silver-care towns grouping a population of elders with various conditions. The rest of this paper is organized as follows: section II describes the proposed system’s architecture, section III is Figure 1 shows the deployment of our system for healthcare 978-1-4799-0724-3/13/$31.00 ©2013 IEEE 22 2013 IEEE GCC Conference and exhibition, November 17-20, Doha, Qatar provisioning for elders in their homes. Each elder living in a set of common communication interfaces for connecting a smart home where medical sensors, environmental sensors, transducers to microprocessor-based systems, instruments, and and video cameras are installed is monitored by its LLPU networks in a network-independent environment [4]. A smart which is responsible of detecting critical situations based on transducer is composed of a sensor or actuator, a processing his condition. For instance, a patient with chronic heart failure unit, and a communication interface. An IEEE 1451 smart would have an LLPU that monitors his blood pressure, heart transducer is divided into a Network Capable Application rate, and of course abnormal behavior such as fall detection, processor (NCAP) and a Transducer Interface Module (TIM). while a patient with Dementia would have an LLPU that The NCAP is responsible of application processing as well focuses on the patient’s behavior. as communication with the network. The TIM module is composed of sensors and/or actuators, signal conditioning HLPU and data conversion units. The TIM module includes the Transducer Electronic Data Sheets (TEDS) where information about the transducer is stored. The TEDS are provided by the manufacturer and among the information it can include is information about the manufacturer, measurement range and calibration. The Transducer Independent Interface (TII) defines the communication medium and the protocol for transferring LLPU LLPU sensor information between the TIM and the NCAP. Figure 2 shows the architecture of the IEEE 1451 standards. SPUs SPUs Network Fig. 1. System Architecture for Home Monitoring The detailed description of each layer and the system func- tionalities is presented in [2]. This paper is focused on the so- Network library lution to the interoperability issue caused by the heterogeneous sensors that can be deployed. A formal sensor description NCAP IEEE 1451.1 provided to the SPU allows the intelligent integration of the sensor to the system by understanding its characteristics. Using IEEE 1451.0 standards in sensor systems description provides a reliable solution to the interoperability issue of heterogeneous sensor IEEE 1451.X networks. III. SENSOR STANDARDS Physical layer IEEE 1451.X There is a wide selection of sensors suitable for our transport mechanism application. In fact, a simple room temperature measurement can be performed by various sensors. They can be analog or digital, the measured temperature can be in Celsius or IEEE 1451.X Fahrenheit, they can be on a mote with other sensors and a TEDS processing unit or a single sensor, etc. Standardization, for IEEE 1451.0 communicating information about sensors and sensor data, is a key requirement for the interoperability of our system. There Signal Processing & conversion exist a number of sensor standards and the description of each and every one of them is out of the scope of this paper, instead we will focus on the ones that are the most widely used. TIM The Institute of Electrical and Electronics Engineers (IEEE) and the Open Geospatial Consortium (OGC) propose adopted Transducer standards that can be used in our system. A. IEEE 1451 family of standards Fig. 2. The family of IEEE 1451 standards [5] In response to the industry’s need for a set of standardized sensor interfaces, the IEEE Instrumentation and Measurement B. Sensor Web Enablement Society’s Technical Committee on Sensor Technology has sponsored the development of a suite of smart transducer The OGC Sensor Web Enablement (SWE) standards enable interface standards for sensors and actuators, known as the the Web-based discovery, exchange, and processing of sensor IEEE 1451 [3]. The IEEE 1451 family of standards defines observations, as well as the tasking of sensor systems [6]. The 23 2013 IEEE GCC Conference and exhibition, November 17-20, Doha, Qatar SWE suit is composed of a number of standards that can be The IEEE 1451 family of standards