ENS Cachan-Bretagne Bruz, France
Off-the-shelf wireless sensing devices open up interesting perspectives for biomedical monitoring. Yet because of their limited processing and transmission capacities most applica- tions considered to date imply either indoor real-time data streaming, or ambulatory data recording. In this paper we investigate the possibility of using disruption-tolerant wire- less sensors to monitor the biomedical parameters of ath- letes during outdoor sports events. We focus on a scenario we believe to be a most challenging one: the ECG monitor- ing of runners during a marathon race, using off-the shelf sensing devices and a limited number of base stations de- ployed along the marathon route. Preliminary experiments conducted during an intra-campus sports event show that such a scenario is indeed viable, although special attention must be paid to supporting episodic, low-rate transmissions between sensors carried by runners and road-side base sta- tions.
This paper provides a synthesis of results we pre- sented in September 2012 at the 7th International Con- ference on Body Area Networks (BODYNETS'12) in Oslo , and in December 2012 at the 6th International Conference on Ubiquitous Computing and Ambient In- telligence (UCAmI'12) in Madrid . Both communica- tions addressed the same marathon scenario, which is the test-case we consider in project CoMoBioS (Com- municating Mobile Biometric Sensors). This scenario is described in Section 2. Related work pertaining to biomedical monitoring and to delay/disruption toler- ant networking is discussed in Section 3. Section 4 pro- vides an overview of the sensors we use in project Co- MoBioS. The constraints presented by such sensors in order to meet the requirements of the marathon sce- nario are discussed in Section 5. In Section 6 we re- port on a rst eld experiment we conducted in order to check whether IEEE 802.15.4 (ZigBee) technology can be used to support the transmissions between sen- sors worn by runners and roadside base stations. Re- sults of this experiment were presented at BODYNET 2012. They show that 802.15.4 transmissions can hardly meet the requirements of the marathon scenario. An alternative approach was therefore proposed, and pre- sented at UCAmI 2012.This new approach is presented in Section 7. It involves using Android smartphones as relays between ECG sensors and roadside base sta- tions, and IEEE 802.11 (Wi-Fi) transmissions on the smartphone-to-base-station segment. Field experiments conrm that it is a lot more viable, as it allows to transmit ECG episodically with no data loss. Section 8 presents new results that were obtained using 3G trans- missions instead of Wi-Fi transmissions. These results show that although 3G transmission may appear to be the obvious solution to collect biomedical data on marathon runners, this solution is quite power-greedy and is therefore not necessarily the most eective one. Section 9 discusses power consumption issues, and Sec- tion 10 concludes this paper
Index Terms—Wirelessdisruption-tolerantnetworking, sensor
networking, biomedical monitoring
I. I NTRODUCTION
Wireless Biomedical Sensor Networks (WBSN) are a va- riety of wireless sensor networks (WSN) in which sensors are dedicated to the monitoring of health parameters, such as physiological , kinematics  and ambient  parameters. Such sensors open up new opportunities in health care, as they allow long-term, continuous monitoring of patients in clinical environment, but also that of ambulatory patients at home . In the latter case the cost and inconvenience of regular visits to the physician can be avoided, or at least significantly reduced. As a general rule one or several lightweight, battery- powered sensors are attached to the patient, and a wireless base station is installed in the patient’s surroundings. This base station can be configured so as to store the data received from the sensors. It can also forward these data directly to a remote site, such as a physician’s desktop computer or a hospital’s monitoring center. In any case, since the sensors are wireless the patient can move freely around the base station, while an endless stream of data flows from the sensors he/she is carrying to the base station. This freedom of movement is however limited by the short transmission range of the wireless sensors. Most sensors implement low-power radio transmission standards (such as Bluetooth or ZigBee), with which actual transmission ranges are usually between a few meters (indoor) and up to a hundred meters (outdoor).
The concept of Disruption-TolerantNetworking 3 (DTN) is a means to cope
with challenging situations where continuous transmissions cannot be guaran- teed. When considering a scenario involving mobile wireless devices, the general idea is to apply the store, carry, and forward principle: a device that is temporar- ily disconnected from the network can store data for a while in a local cache, carry these data while moving towards a location where network connectivity can be restored, and ultimately forward the data when circumstances permit.
classes, but also out of the campus (at home, during week-end trips, etc.). Several trials were conducted during that campaign, with du- rations ranging between a couple of weeks and 6 months.
The netbooks were Dell Inspiron Mini 9 and Mini 10, running an Ubuntu/Linux system. The Wi-Fi interface on each netbook was configured to operate by default in ad hoc mode, using an SSID dedicated to the experiment. The users were not allowed to switch this interface to managed mode, thus preventing wireless connec- tions to access points that may be present in their environment. However, they had the possibility to access the Internet sporadically using the builtin Ethernet interface, while wireless communication was reserved for opportunistic communication with DoDWAN.
Since deploying hundreds of base stations along a marathon route is hardly an option for organizational and nancial reasons, our approach is based on the premise that only a sparse coverage of the route needs to be ensured, using a reasonable number of base stations. A disruption-tolerant solution for data gath- ering must therefore be implemented, using the store-carry-and-forward princi- ple. This principle is the foundation of Disruption-TolerantNetworking (DTN): a mobile node that is temporarily disconnected from the rest of the network can store data (or messages) in a local cache, carry these data for a while, and for- ward them later when circumstances permit . In our scenario, the ECG sensor carried by a runner captures data continuously and transmits these data to the smartphone, which stores these data locally. Whenever the runner passes by a BS, a transient radio contact occurs between the smartphone and that BS. This contact is exploited by the smartphone to upload bundles of data to the BS, which in turn can forward these bundles to the monitoring center (see Fig. 1). The distance between successive base stations and the speed of the runner deter- mine how often fresh data can be sent to the monitoring center. According to cardiologists, a physician monitoring the cardiac activity of marathon runners should receive updated data for each runner at least every 5 to 10 minutes, in order to be able to detect arrhythmias and prevent incidents. Considering the pace of an average runner this implies that base stations should be placed about 1 to 2 km apart. With this approach, ten to twenty base stations are sucient to cover a marathon route satisfactorily.
Research Efforts on Information-Centric Networking
Hassine Moungla, Universit´e de Paris, LIPADE, F-75006 Paris, France (firstname.lastname@example.org)
I. I NTRODUCTION
Information-Centric Networking (ICN)  has been pro- posed as a new architecture for the future Internet, addressing many issues in the current IP-based networks, such as routing process, scalability issue, and content sharing performance. ICN integrates all network functionalities around the name of content rather than the address of the network, in a way to ensure efficient data dissemination and access.
For Cloud Networking, SAIL will develop networking functions for applica- tions with highly variable demands, integrating these functions with computing and storage, along with the necessary tools for management and security. In that way, the allocation of both computing and networking resources will be solved as only one optimisation problem. A prototype of the proposed solutions will be developed and reﬁned under the course of the project. The prototype will be hosted on some partners premises distributed across Europe. An iterative approach to research will be taken, whereby proposed solutions will be assessed through prototyping, providing feedback to the architecture, management, and security tasks of CloNe. Just as important, the workpackage will provide a mi- gration path whereby developed technologies will be deployed in the existing Internet and standardized.
Fig. 8: Efficiency of large-scale networks in presence of faults.
7 Conclusions and Perspectives
In this paper we have presented CoopStor that targets at achieving in a reliable data collection in fault and delay tolerantwireless networks. We have shown to what extent such a mechanism would be profitable during the data collection phase of a time-driven and event-driven monitoring application and even more, in many-to-one topologies where the congestion is prominent around the root of the tree. Our approach considerably improves the reliability in presence of faults. Even when the routing protocol has to reconstruct some routes with e.g. a local repair, the network infrastructure is able to store efficiently the packets to still provide high reliability. CoopStor reduces also the delay since it triggers a storing
In order to validate this implementation, a rigorous testing approach can be used. Au- tomatic failure injection is a general technique suitable for evaluating the effectiveness and robustness of the distributed applications against various and complex failure scenarios.
After having validated the fault tolerant implementation, it is necessary to evaluate its performance, in order to adapt the best protocol suitable for an actual distributed system. Fault-Tolerant distributed applications are classically evaluated without failures. However, performances under a failure-prone environment is also a significant information to evaluate and tune a fault-tolerant distributed system. Automatic failure injection is desirable to evaluate fairly different heuristics or parameters under the same failure conditions.
Abstract. Recent researches in communication systems are leading to the multiplication of
communication technologies. Because of this trend there is now a very wide range of different kinds of networks from copper lines for telephony to high speed fibres, as well as satellite or wireless mobile networks. It would then be very useful to be capable of using all these new communication networks all together. We call this domain related to the use by an application of several different networks “multi-networking”. But the problematic of multi-networking is two folds: (1) First, it can be really interesting to have several network access and to be able to use them in parallel. For instance, it can consist, in the case of digital and interactive TV, of using digital satellite channels for broadcasting audio and video, and using the wire Internet or an ISDN (Integrated Services Data Network) network to send specific data to dedicated users. This is what we call “parallel multi-networking”. (2) The second folder of this problematic deals with guaranteeing Quality of Service (QoS) while connections cross several networks or domains, especially when there are firewalls or NAT (Network Address Translation) servers in between that break the end to end IP model. In addition, the introduction of wireless or satellite links that have high delays and loss ratio inside the Internet can lead to important QoS degradation as wire Internet protocols are not efficient on wireless and satellite links. This aspect of the problematic is called “serial multi-networking”. This second aspect has been much more addressed in a recent past than the first one. It lead to some specific solutions, most of the time application oriented, as caching for web application for instance. To cope with other problems, as the introduction of satellite links in the Internet, proxies system have been designed to handle data flows before entering the satellite link. Proxies are, there, in charge of performing some spoofing operations. But in any case, even if there are some application specific solutions, or some network dedicated approaches, none of them are able to handle live real time traffic.
within the computational environment: the hardware and standards on which our contemporary infrastructure is based on. So we have to recall that code is not only electronic: their effects extend to the physical world. Code and digital media are unstable because new uses are continuously foreseen. Design by disruption might respond to stabilizing practices with aesthetic provocations.
TABLE 4. Comparison of simulated displacement-tolerant performance.
FIGURE 8. Fabricated printed spiral resonator with capacitive plates: Top (Left); Bottom (Right).
0 till 1 refers to the ratio of lateral shift ax or ay to the axial distance. The corresponding simulated and measure- ment results as well as measurement setups are depicted in Fig. 11 and Fig. 12. Reasonable agreement between sim- ulated and measured results are observed for both plots. Table 5 summarizes displacement-tolerant performance of proposed design. Variation ratio, 1VR is used to assess the extent of PTE sustainability and computed as :
In this article, a new WSN platform termed LiveWSN is designed and implemented. LiveWSN tar- gets to address the current WSN challenges such as the memory constraint, the energy limitation, the remote reprogramming, and the fault tolerance. On one hand, some new design concepts are applied in LiveWSN, such as the hierarchical shared-stack scheduling and the pre-linked native-code reprogramming. With these mechanisms, the memory cost of the WSN platform can be decreased significantly. Moreover, the repro- gramming performance of the WSN nodes can be improved soundly. On the other hand, the new research approach which addresses the WSN challenges by com- bining both the software technique and the multi-core hardware technique (rather than only the software technique) is realized in LiveWSN. By means of the multi-core hardware infrastructure, the energy conser- vation and the fault-tolerant performance of the WSN nodes can be optimized efficiently. Due to the above mechanisms, LiveWSN becomes the WSN platform which is memory efficient, energy efficient, reprogram- mable, and fault tolerant.
In this paper, we investigate two different atomic topologies to highlight different problems that may occur in a wireless multi-hop mesh communication. The first one is a basic multi- hop linear topology, where all packet are forwarded from one source node S to a destination node D using relay nodes. In our case, we choose a topology where three nodes relay the frames from S to D (cf. Fig. 1(a)). The more relays are exploited, the higher the odds for the transmission to fail. Typ- ically, end-to-end communications exceeding four to five hops get difficult to implement in practice. The second topology investigated is the 2-relay/2-flow topology of Fig. 1(b). Here, the two relays have to forward packets that belong to two flows, simultaneously. The first flow is emitted by S 1 going to
In this paper, we present the concept of MB-OFDM for optical networking and analyze its potential compared to trend- setting technologies. This paper is ordered as follows. The second section introduces the technological principles of MB- OFDM technique. In the third section the different types of flexibility offered by the MB-OFDM are described and modeled. Finally, in a fourth section, we compare three simple scenarios, purely opaque node, purely transparent node and MB-OFDM node in terms of optical WDM channels and electrical interfaces numbers.
The rage of social media is taking over everyone nowadays. Billions of people use social media for learning, marketing, shopping and decision making. We will present its different uses:
1. Social media in education: Social media today made education anywhere and anytime, many studies have confirmed that the majority of students spend more time on social networking platforms which led institutions to integrate social media into the classroom curriculum to serve as useful tool to enhance students’ learning. This form of learning offers many benefits to both educators and students such as encouraging the real time student engagement in courses to enhance the connection between educators and students.