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The Internet of Things (IoT) applications such as smart grids, smart agriculture, smart cities, and e-healthcare are popular nowadays. Generally, IoT end devices are extremely sensitive to the utilization of energy. The medium access control (MAC) layer is responsible for coordination and access of the IoT devices. It is essential to design an efficient MAC protocol for achieving high throughput in IoT. Duty cycling is a fundamental process in wireless networks and also an energy-saving necessity if nodes are required to operate for more than a few days. Numerous MAC protocols along with different objectives have been proposed for the IoT. However, to the best of our knowledge, only limited work has been performed dedicated to covering MAC and radio duty cycling (RDC). Therefore, in this study, we propose a systematic cataloging system and use if to organize the most important MAC and RDC proposals. In this catalog, each protocol has been categorized into main ideas, advantages, applications, limitations, innovative features, and potential future improvements. Our critical analysis is different from previous research studies, as we have fully covered all recent studies in this domain. We discuss challenges and future research directions. [ABSTRACT FROM AUTHOR]

An access control mechanism plays a critical role in new node deployment within a resource-constrained Wireless Sensor Networks. The deployment of a new node is inevitable either due to the outage of power or nodes getting compromised due to the adversary's attacks. The access control scheme prevents malicious node deployment and also allows a new node to establish a shared key with its neighbors for secure communication. Besides having low communication and computational overheads, an access control mechanism must suffice to specific security and functional requirements for their practical implementations. In this paper, a provable and practical access control scheme based on Elliptical Curve Cryptography (ECC) has been presented. The proposed access control scheme supports node privacy while addressing all other major functional and security requirements. The formal validation of the proposed scheme has been carried out using automated validation of internet security protocols and applications (AVISPA) and Scyther tools. A comparative study of the proposed scheme with the existing schemes has been carried out on various security and functional requirements suggesting a better trade-off. Finally, practical experimentation on TinyOS and MICAz motes has been carried out to provide detailed energy analysis and test-bed implementation of the proposed scheme. [ABSTRACT FROM AUTHOR]

Recent work in wireless embedded networked systems has followed heterogeneous designs, incorporating a mixture of elements from extremely constrained 8- or 16-bit “Motes” to less resource- constrained 32-bit embedded “Microservers”.Emstar is a software environment for developing and deploying complex applications on such heterogeneous networks. Emstar is designed to leverage the additional resources of Microservers by trading-off some performance for system robustness in sensor network applications. It enables fault isolation, fault tolerance, system visiblity, in-field debugging, and resource sharing across multiple applications.In order to accomplish these objectives, Emstar is designed to run as a multi-process system and consists of libraries that implement message-passing IPC primitives, services that support networking, sensing, and time synchronization, and tools that support simulation, emulation, and visualization of live systems, both real and simulated. We evaluate this work by discussing the Acoustic ENSBox, a platform for distributed acoustic sensing that we built using Emstar. We show that by leveraging existing Emstar services, we are able to significantly reduce development time while achieving a high degree of robustness. We also show that a sample application was developed much more quickly on this platform than it would have been otherwise.

Existing approaches used to develop compact low-power multichannel wireless neural recording systems range from creating custom-integrated circuits to assembling commercial-off-the-shelf (COTS) PC-based components. Custom-integrated-circuit designs yield extremely compact and low-power devices at the expense of high development and upgrade costs and turn-around times, while assembling COTS-PC-technology yields high performance at the expense of large system size and increased power consumption. To achieve a balance between implementing an ultra-compact custom-fabricated neural transceiver and assembling COTS-PC-technology, an overlay of a neural interface upon the TinyOS-based MICA2 platform is described. The system amplifies, digitally encodes, and transmits neural signals real-time at a rate of 9.6 kbps, while consuming less than 66 mW of power. The neural signals are received and forwarded to a client PC over a serial connection. This data rate can be divided for recording on up to 6 channels, with a resolution of 8 bits/sample. This work demonstrates the strengths and limitations of the TinyOS-based sensor technology as a foundation for chronic remote biological monitoring applications and, thus, provides an opportunity to create a system that can leverage from the frequent networking and communications advancements being made by the global TinyOS-development community.

Recently deployed Wireless Sensor Network systems (WSNs) are increasingly following heterogeneous designs, incorporating a mixture of elements with widely varying capabilities. The development and deployment of WSNs rides heavily on the availability of simulation, emulation, visualization and analysis support. In this work, we develop tools specifically to support heterogeneous systems, as well as to support the measurement and visualization of operational systems that is critical to addressing the inevitable problems that crop up in deployment. Our system differs from related systems in three key ways: in its ability to simulate and emulate heterogeneous systems in their entirety, in its extensive support for integration and interoperability between motes and microservers, and in its unified set of tools that capture, view, and analyze real time debugging information from simulations, emulations, and deployments.

Recently, the Internet of Things (IoT) concept has attracted a lot of attention due to its capability to translate our physical world into a digital cyber world with meaningful information. The IoT devices are smaller in size, sheer in number, contain less memory, use less energy, and have more computational capabilities. These scarce resources for IoT devices are powered by small operating systems (OSs) that are specially designed to support the IoT devices' diverse applications and operational requirements. These IoT OSs are responsible for managing the constrained resources of IoT devices efficiently and in a timely manner. In this paper, discussions on IoT devices and OS resource management are provided. In detail, the resource management mechanisms of the state-of-the-art IoT OSs, such as Contiki, TinyOS, and FreeRTOS, are investigated. The different dimensions of their resource management approaches (including process management, memory management, energy management, communication management, and file management) are studied, and their advantages and limitations are highlighted.

In this article, we develop a system based on WSN platform to measure the data of crop parameters for the agriculturists aimed to enhance the quality and quality of the crops. The proposed system will minimize the exhaustive field visits of the farmers. This system will facilitate the precision agriculture by measuring three most key parameters (temperature, humidity and light) of the crops. The proposed system consists of IRIS motes MDA100CB data board, and MIB520 USB interface board. These are considered as sink and sensor nodes respectively. TinyOS is used to develop the code for WSN nodes, and GUI device is composed in Microsoft Visual Studio-2008 for displaying the measured data and stored in data base accordingly. ZigBee IEEE 802.15.4 and direct topology are utilized for the correspondence of sensor nodes with the base station

To solve the problem of the priorities of network traffic and improve the applicability of multi-access for communication systems, a two-level asymmetric polling control system was proposed, in which the central node adopts an exhaustive access policy and the normal nodes adopt an asymmetric 1-limited (K = 1) access policy. This model can distinguish network traffic priorities as well as guarantee fairness of the system. Using a probability generating function and embedded Markov chain, the system model was established. Through the accurate mathematical analysis of the system model, the mathematical analytical formulas of important system performance parameters, such as the mean queue length of nodes and the mean delay of information packets, were obtained. The model provides high-quality services for high-priority nodes while maintaining the quality of service at low-priority nodes. Finally, the polling access control strategy was implemented by Tinyos. [ABSTRACT FROM AUTHOR]

Advances in technology call for a parallel evolution in the software. New techniques are needed to support this dynamism, to track and guide its evolution process. This applies especially in the field of embedded systems, and certainly in Wireless Sensor Networks (WSNs), where hardware platforms and software environments change very quickly. Commonly, operating systems play a key role in the development process of any application. The most used operating system in WSNs is TinyOS, currently at its TinyOS 2.1.2 version. The evolution from TinyOS 1.x and TinyOS 2.x made the applications developed on TinyOS 1.x obsolete. In other words, these applications are not compatible out-of-the-box with TinyOS 2.x and require a porting action. In this paper, we discuss on the porting of embedded system (i.e., Wireless Sensor Networks) applications in response to operating systems’ evolution. In particular, using a model-based approach, we report the porting we did of Agilla, a Mobile-Agent Middleware (MAMW) for WSNs, on TinyOS 2.x, which we refer to as Agilla 2. We also provide a comparative analysis about the characteristics of Agilla 2 versus Agilla. The proposed Agilla 2 is compatible with TinyOS 2.x, has full capabilities and provides new features, as shown by the maintainability and performance measurement presented in this paper. An additional valuable result is the architectural modeling of Agilla and Agilla 2, missing before, which extends its documentation and improves its maintainability.

Although much work has been done since wireless sensor networks appeared, there is not a great deal of information available on real deployments that incorporate basic features associated with these networks, in particular multihop routing and long lifetimes features. In this article, an environmental monitoring application (Internet of Things oriented) is described, where temperature and relative humidity samples are taken by each mote at a rate of 2 samples/min and sent to a sink using multihop routing. Our goal is to analyse the different strategies to gather the information from the different motes in this context. The trade-offs between 'sending always' and 'buffering locally' approaches were analysed and validated experimentally, taking into account power consumption, lifetime, efficiency and reliability. When buffering locally, different options were considered such as saving in either local RAM or FLASH memory, as well different alternatives to reduce overhead with different packet sizes. The conclusion is that in terms of energy and durability, the best option is to reduce the overhead. Nevertheless, sending larger packets is not worthy when the probability of retransmission is high. If real-time monitoring is required, then sending always is better than buffering locally. [ABSTRACT FROM AUTHOR]

Current era of advancement in micro-electroniccommunication and networking has inspired researchers to analyse, design and develop cost effective integrated sensing, computing and communicating through Wireless Sensor Network (WSN). WSN is a group of lowpowered, tiny devices capable to sense the environment, gather and process that sensed data and communicating with each other to achieve certain results of common tasks. In this paper, the results and models of experiments supported and using the Wireless sensor equipment with distances extending from 80m to 100m are presented. The results illustrate that Short distance wireless sensor networks (SDWSN) are conceivable and the distance affect the quality of those links. [ABSTRACT FROM AUTHOR]

Wireless sensor networks are used to sample the environment in a distributed way. Therefore, it is mandatory for all of the measurements to be tightly synchronized in order to guarantee that every sensor is sampling the environment at the exact same instant of time. The synchronization drift gets bigger in environments suffering from temperature variations. Thus, this work is focused on improving time synchronization under deployments with temperature variations. The working hypothesis demonstrated in this work is that the clock skew of two nodes (the ratio of the real frequencies of the oscillators) is composed of a multiplicative combination of two main components: the clock skew due to the variations between the cut of the crystal of each oscillator and the clock skew due to the different temperatures affecting the nodes. By applying a nonlinear filtering, the homomorphic filtering, both components are separated in an effective way. A correction factor based on temperature, which can be applied to any synchronization protocol, is proposed. For testing it, an improvement of the FTSP synchronization protocol has been developed and physically tested under temperature variation scenarios using TelosB motes flashed with the IEEE 802.15.4 implementation supplied by TinyOS. [ABSTRACT FROM AUTHOR]

This paper deals with the distance estimation issue in 802.15.4 wireless sensor networks. On a basis of signal strength of received frames a distance between two sensor nodes using the log-normal shadowing radio propagation model (LNSM) is estimated. Basic problems of signal strength based systems are variation of RSSI parameter and correct calibration of coefficients for the LNSM model. For distance estimation in wireless networks, static and dynamic methods of calibration were already introduced. Static calibration has significant drawback in adaptation to the dynamical environment changes. Proposed work deals with an experimental validation of dynamic calibration method for distance estimation in wireless sensor networks. This method for dynamic estimation of radio environment parameters results in the significant improvements in the distance estimation accuracy in comparison with the known static methods.

In this paper we present the design and implementation of the Constrained Application Protocol (CoAP) for TinyOS, which we refer to as TinyCoAP. CoAP seeks to apply the same application transfer paradigm and basic features of HTTP to constrained networks, while maintaining a simple design and low overhead. The design constraints of Wireless Sensor Networks (WSNs) require special attention in the design process of the CoAP implementation. We argue that better performance and minimal resource consumption can be achieved developing a native library for the operating system embedded in the network. TinyOS already includes in its distribution an implementation of CoAP called CoapBlip. However, this is based on a library not originally designed to meet the requirements of TinyOS. We demonstrate the effectiveness of our approach by a comprehensive performance evaluation. In particular, we test and evaluate TinyCoAP and CoapBlip in a real scenario, as well as solutions based on HTTP. The evaluation is performed in terms of latency, memory occupation, and energy consumption. Furthermore, we evaluate the reliability of each solution by measuring the goodput obtained in a channel affected by Rayleigh fading. We also include a study on the effects that high workloads have on a server.

Although much research in the area of Wireless Multimedia Sensor Networks (WMSNs) has been done in recent years, the programming of sensor nodes is still time-consuming and tedious. It requires expertise in low-level programming, mainly because of the use of resource constrained hardware and also the low level API provided by current operating systems. The code of the resulting systems has typically no clear separation between application and system logic. This minimizes the possibility of reusing code and often leads to the necessity of major changes when the underlying platform is changed. In this paper, we present a service oriented middleware named SOMM to support application development for WMSNs. The main goal of SOMM is to enable the development of modifiable and scalable WMSN applications. A network which uses the SOMM is capable of providing multiple services to multiple clients at the same time with the specified Quality of Service (QoS). SOMM uses a virtual machine with the ability to support mobile agents. Services in SOMM are provided by mobile agents and SOMM also provides a t space on each node which agents can use to communicate with each other.

A technology drift is currently taking place from traditional battery-powered sensor networks, which exhibit limited lifetime, to the new Energy-Harvesting Wireless Sensor Networks (EH-WSN), which open the way towards self-sustained operation. However, this emergent modality also brings up new challenges, especially due to the time-varying nature and unpredictability of ambient energy sources. Most proposals for implementing EH-WSN rely on heuristic approaches to redesign the duty-cycling mechanism at the MAC layer, with the ultimate goal of optimizing network performance while preserving self-sustained and continuous operation. In contrast to the common system-wide reduced duty cycle of battery-powered sensor networks, the duty cycle in EH-WSN is much larger and adapted to the energy harvesting rate and traffic load of each node in the network. In this paper, we focus on solar-based EH-WSN devoted to environmental monitoring. In contrast to current works, we follow an analytical approach, which results into closed-form expressions for the duty cycle and initial energy storage that guarantee self-sustained operation to any node in a solar-based EH-WSN. To center the analysis, we consider TinyOS sensor nodes, though we postulate that the essential components of the obtained formulation will contribute to further develop duty cycle adaptation schemes for TinyOS and other software platforms.

In this paper four wireless sensor network operating systems are compared in terms of power consumption. The analysis takes into account the most common operating systems—TinyOS v1.0, TinyOS v2.0, Mantis and Contiki—running on Tmote Sky and MICAz devices. With the objective of ensuring a fair evaluation, a benchmark composed of four applications has been developed, covering the most typical tasks that a Wireless Sensor Network performs. The results show the instant and average current consumption of the devices during the execution of these applications. The experimental measurements provide a good insight into the power mode in which the device components are running at every moment, and they can be used to compare the performance of different operating systems executing the same tasks.

This paper presents the design of a new wireless sensor node (GAIA Soil-Mote) for precision horticulture applications which permits the use of precision agricultural instruments based on the SDI-12 standard. Wireless communication is achieved with a transceiver compliant with the IEEE 802.15.4 standard. The GAIA Soil-Mote software implementation is based on TinyOS. A two-phase methodology was devised to validate the design of this sensor node. The first phase consisted of laboratory validation of the proposed hardware and software solution, including a study on power consumption and autonomy. The second phase consisted of implementing a monitoring application in a real broccoli (Brassica oleracea L. var Marathon) crop in Campo de Cartagena in south-east Spain. In this way the sensor node was validated in real operating conditions. This type of application was chosen because there is a large potential market for it in the farming sector, especially for the development of precision agriculture applications.

Currently, the first-come-first-service (FCFS) non-preempting strategy is adopted in TinyOS task scheduling system, which is not able to give emergency tasks quick response. In this study, a new preempting two-level priority strategy based on least laxity first (LLF) in TinyOS. In the strategy, the hard real-time tasks in the highest priority queue could preempt the task in soft real-time, which met system requirement for the real-time response and improved processor's response speed; soft real-time tasks in the secondary priority queue was served FCFS scheduling algorithm without extra overhead. The TinyOS test result indicated this strategy can improve the response of TinyOS to real-time tasks with little energy consumption and storage space. [ABSTRACT FROM AUTHOR]

Wireless Sensor Networks (WSNs) are often deployed in remote and hostile environments to monitor the mission critical tasks. In such environments, cooperation among nodes plays a vital role for successful execution of protocol operations. However, node cooperation may not be guaranteed when malicious activities are present in the WSNs. Trust management based security has received considerable attention to use along with cryptography based security to improve the cooperation among nodes in the presence of malicious activities in the network. This paper proposes the self-adaptive trust model for cooperative geographic routing in WSNs. Unlike existing trust models, nodes running the proposed trust model systematically observe the behavior of their neighboring nodes and evaluate the trust values with adaptive weight assessment. The proposed method has been integrated with conventional Greedy Perimeter Stateless Routing (GPSR) protocol. Further, it has been coded with nesC programming in TinyOS environment and evaluated on a WSN testbed consisting of 15 Telosb sensor nodes. The experimental results show that the proposed method significantly improved the packet delivery ratio in the presence of packet dropping and modification attacks. [ABSTRACT FROM AUTHOR]

In this paper, we face the implementation of a non-linear kernel method for regression on a wireless sensor network (WSN) based on MICAz motes. The operating system used is TinyOS 2.1.1. The algorithm estimates the value of some magnitude from the measurements of the motes in a distributed approach where information and computations are performed asynchronously. This proposal includes a research on the potential problems encountered along with the developed solutions. Namely, matrix and floating computations, acknowledgement mechanisms and data loss. [ABSTRACT FROM AUTHOR]