Oum-El-Kheir Aktouf

RFID System On-line Testing Based on the Evaluation of the Tags Read-Error-Rate

RFID systems are complex heterogeneous systems, consisting of analog and digital hardware components and software components. RFID technologies are often used into critical domains or within harsh environments. But as RFID systems are only based on low cost and low-performance equipments, they do not always ensure robust communications. All these points make the on-line testing of RFID systems a very complex task. This article proposes a new on-line testing approach allowing the detection of tags defects to enhance system reliability and availability. This approach is based on the characterization of a statistical system parameter, the tag Read-Error-Rate, to perform the on-line detection of faulty RFID components. As an introduction to RFID tags on-line testing, a Failure Modes and Effects Analysis first describes the effects of the potential defects on these systems. Second, a SystemC model of the RFID system is proposed as a way to evaluate the proposed test solutions. Then, our solution to enhance system reliability is presented. Finally, validation of our on-line test approach using system-level simulation is discussed.

Read-Error-Rate evaluation for RFID system on-line testing

RFID systems are complex hybrid systems, consisting of analog and digital hardware and software components. RFID technologies are often used into critical domains or into harsh environments. But RFID system is only based on low cost equipments which then do not allow achieving robust communications. All these points make the on-line testing of RFID systems a very complex task. Thus, this article proposes the on-line characterization of a statistical system parameter, the Read-Error-Rate, to perform the on-line detection of faulty RFID components. As an introduction to the on-line testing of RFID systems, a FMEA first describes the effects on these systems of potential defects impacting the communication part. Second, a SystemC model of the RFID system is discussed as a way to evaluate the proposed test solutions. Finally, the way the maximal Read-Error-Rate can be determined using system-level simulation is explained.

Monitoring of RFID failures resulting from LLRP misconfigurations

Radio frequency identification (RFID) technology is becoming a pervasive technology that is used in our daily lives and in a variety of domains, especially in critical domains such as medical field and transportation systems. Several standards are specified to support the use of this technology. LLRP protocol (Low Level Reader Protocol) is one of them. It is the communication protocol between RFID readers and a client (a middleware or an end user application). It uses several XML based specifications to set up a huge number of parameters in the readers configuration in order to perform a correct tag inventory. Since this protocol is relatively new, there is no significant fault-tolerant mechanism that takes in consideration the protocols behavior. In this paper we propose an approach that monitors RFID failures resulting from misconfiguration errors of LLRP protocol by using the logging system of this protocol.

An Extended LLRP Model for RFID System Test and Diagnosis

In recent years, radio frequency identification (RFID) systems have been increasingly used in critical domains such as medical field or real-time processing domains. Although important efforts have been made to make this technology more reliable and fault-tolerant, more research is needed to meet the increasing dependability requirements. In this article, we propose a dependability approach consisting in two steps. The first one is an analysis of RFID systems in order to identify potential failures of RFID middleware components and their effects on the whole system. The second one is the modelling of the communication behaviour of RFID systems (that is represented by Low Level Reader Protocol) as a finite state machine. This protocol FSM will be extended to take into consideration the failures identified in the first step and serves as a diagnosis and test tool for the RFID system.

Test Model and Coverage Analysis for Location-based Mobile Services

Location-based services (LBS) are very important mobile app services, which provide diverse mobility services for mobile users anywhere and anytime. This brings new demands, issues, and challenges in mobile application testing. Today, mobile applications provide location-based service functions based on dynamic location contexts, mobile users and their travel patterns to deliver location-based mobile data, and service actions. Current software testing methods do not consider location-based validation coverage. Hence, there is a lack of research results addressing location-based mobile application testing. This paper focuses on mobile LBS testing. A novel test object model is proposed for quality validation of location-based mobile information services. In addition, the related test coverage metrics are also presented. These metrics can be useful for test engineers in designing test cases. A case study based on student testers is reported to demonstrate the potential application of the proposed model.

Diagnosis service for embedded software component based systems

This paper studies the fault diagnosis of component-based applications, especially embedded ones. The principle of the proposed diagnosis technique is to implement inter-component tests in order to detect and locate faulty components without component replication. A diagnosis service for embedded software component based systems is developed. Its advantages are application autonomy, cost-effectiveness and better usage of system resources. Such advantages are very important for embedded systems.

Online data fault detection in wireless sensor networks

The critical applications of wireless sensor networks, the increased data faults and their impact on decision making reveal the importance of adopting online techniques for data fault detection and diagnosis. Keeping in mind the hardware limitations of sensors, this work focuses on complementary signal processing techniques (temporal, spatial correlation and self organizing map) in order to cover several types of data faults, reduce the misdetection rate and also isolate faults when possible by specifying the defaulting sensors. The methods applied to a real database show that 31.6% of data are faulty by applying SOM3D in conjunction with the spatial correlation. The combination of the above technique in addition to the temporal correlation reduces the misdetection by increasing the detection percentage by 17.6%. SOM3D model also helped identifying the least trustful sensors among the network sensors, this can be helpful when reconciling errors.

Read rate profile monitoring for defect detection in RFID Systems

RFID technologies are sometimes used into critical domains where the on-line detection of RFID system defects is a must. Moreover, as RFID systems are based on low cost tags which are often used into harsh environment, they do not always ensure robust functioning. This article proposes a new on-line monitoring approach allowing the detection of system defects to enhance system reliability and availability. This approach is based on the characterization of a statistical system parameter - the tag read rate profile - to perform the on-line detection of faulty RFID components. This monitoring approach is compared to classical monitoring approaches for a real case study and through several fault simulations. Results show that the proposed read rate profile monitoring is more efficient than the existing approaches. In addition, results show that this approach should be combined with an existing approach to maximize the fault detection.

A Fault Fuzzy-ontology for Large Scale Fault-tolerant Wireless Sensor Networks

Fault tolerance is a key research area for many of applications such as those based on sensor network technologies. In a large scale wireless sensor network (WSN), it becomes important to find new methods for fault-tolerance that can meet new application requirements like Internet of things, urbane intelligence and observation systems. The challenge is beyond the limit of a single wireless sensor network and concerns multiple widely interconnected sub networks. The domain of fault grows considerably because of this new configuration. In this context, the paper proposes a fault fuzzy-ontology (FFO) for large scale WSNs to be used within a Web service architecture for diagnosis and testing.

Test and diagnosis of wireless sensor networks applications

Safety critical applications, such as explosion prediction, require continuous and reliable operation of Wireless sensor networks (WSNs). However, validating that a WSN system will function correctly at run time is a hard problem. This is due to the numerous faults one may encounter in the resource-constrained nature of sensor platforms together with the unreliability of the wireless links networks. A holistic fault tolerance approach that addresses all fault issues does not exist. Existing fault tolerance work most likely misses some potential causes of system failures. In this paper, we propose an integrated fault tolerance framework (IFTF) that reduces the false negative by combining a network diagnosis service (component/element level monitoring) with an application testing service (system level monitoring). Thanks to these two complementary services, the maintenance operations will be more efficient leading to a more dependable WSN. From the design view, IFTF offers to the application many tunable parameters that make it suitable for various application needs. Simulation results show that the IFTF reduces the false negative rate of application level failures to 60% with an increase of 4% in power consumption (communication overhead) compared to using solely network diagnosis solutions.