Rajeev Piyare | University of Trento (original) (raw)

Papers by Rajeev Piyare

international conference on embedded wireless systems and networks, Feb 20, 2017

Radio communication remains the primary battery consuming activity in wireless systems. Advances ... more Radio communication remains the primary battery consuming activity in wireless systems. Advances in MAC protocols have enabled significant lifetime improvements, but in systems with low data rate, idle listening, and other communication artifacts can begin to dominate costs. One proposal to combat this is the addition of a second, extremely low power radio component that is always-on. As a consequence of the extremely low power, such radios are incapable of decoding general data, and thus are often delegated the task of listening for a trigger, leading to the terminology wake-up radio , as this extremely low power radio is used to wake up a higher power radio, which is then used for data communication. While wake-up technology has been steadily evolving over the last decade in the hardware arena, few protocols have been developed to exploit it. In this work, we present WaCo , our wake-up radio COOJA extension that allows exploration of the capabilities of the wake-up radio from the desktop environment. We also use our extended simulator to concretely show the potential benefits of the wake-up radio hardware with two, standard data collection protocols. Our results simultaneously confirm that wake-up technology has tremendous potential and that our simulator extension provides an effective mechanism for such exploration.

Low-power and long-range communication tech- nologies such as LoRa are becoming popular in IoT ap... more Low-power and long-range communication tech- nologies such as LoRa are becoming popular in IoT applications due to their ability to cover kilometers range with milliwatt of power consumption. One of the major drawbacks of LoRa is the data latency and the traffic congestion when the number of devices in the network increases. Especially, the latency arises due to the extreme duty cycling of LoRa end-nodes for reducing the overall energy consumption. To overcome this drawback, we propose a heterogeneous network architecture and an energy-efficient On-demand TDMA communication scheme improving both the device lifetime and the data latency of standard LoRa networks. We combine the capabilities of micro- watt wake-up receivers to achieve ultra-low power states and pure asynchronous communication together with the long-range connectivity of LoRa. Experimental results show a data reliability of 100 latency on the order of milliseconds with end devices dissipating less than 46 mJ when activ...

ArXiv, 2018

The performance of wake-up radios must be clearly measured and understood while designing and dev... more The performance of wake-up radios must be clearly measured and understood while designing and developing robust, dependable, and affordable systems, considering both benefits and shortcomings. State-of-the-art WURs display significant diversity in their architecture, processing capability, energy consumption, and receiver sensitivity. Standard methodologies for benchmarking are crucial for quantitatively evaluating the performance of this emerging technology, however, currently, no accepted standard for such quantitative measurement exists. Further, there is no consensus on what objective evaluation procedures and metrics should be used to understand the performance of whole systems exploiting this technology. This lack of standardization has prevented researchers from comparing results and leveraging previous work that could otherwise avoid duplication and speed up the validation process. This paper leads toward an evaluation framework, a benchmark, to enable accurate and repeatabl...

For the Internet of Things to flourish a long lasting energy supply for remotely deployed large- ... more For the Internet of Things to flourish a long lasting energy supply for remotely deployed large- scale sensor networks is of paramount importance. An uninterrupted power supply is required by these nodes to carry out tasks such as sensing, data processing, and data communication. Of these, radio communication remains the primary battery consuming activity in wireless systems. Advances in MAC protocols have enabled significant lifetime improvements by putting the main transceiver in sleep mode for extended periods. However, the sensor nodes still waste energy due to two main issues. First, the nodes periodically wake-up to sample the channel even when there is no data for it to receive, leading to idle listening cost. On the other side, the sending node must repeatedly transmit packets until the receiver wakes up and acknowledges receipt, leading to energy wastage due to over-transmission. In systems with the low data rate, idle listening and over-transmission can begin to dominate e...

Smartphones with built-in sensors promise a conducive, objective way to quantify everyday body mo... more Smartphones with built-in sensors promise a conducive, objective way to quantify everyday body movements and classify those movements into activities. Utilizing smartphone accelerometer data we estimate the following daily activities performed by the user: walking, jogging, using stairs, sitting, standing and lying down. The proposal is tested experimentally via evaluations on real data obtained from 50 test users. The evaluation indicates that the J48 classifier using a window size of 512 samples with 50% overlapping yields the highest accuracy (i.e., up to 96.02%). Keywords—daily activity recognition; feature extraction; WEKA; machine learning

Smartphones with built-in sensors promise a convenient, objective way to evaluate everyday moveme... more Smartphones with built-in sensors promise a convenient, objective way to evaluate everyday movements and recognize those movements into activities. Using accelerometer as a low level sensor data we estimate the following daily activities performed by the user: walking, jogging, walking up stairs, walking down stairs, sitting and standing. Among five common machines learning algorithms: Decision Tree (J48), Naïve Bayes (NB), Support Vector Machines (SVM), Neural Network (NN), and Logistic Regression. NN classifier was found to be the best choice with classification accuracy of more than 95%. It is shown that this method is appropriate and that the phone’s orientation information is not needed.

In this paper, performance analysis of ZigBee networks based on XBee ZB modules have been evaluat... more In this paper, performance analysis of ZigBee networks based on XBee ZB modules have been evaluated in terms of following performance metrics: received signal strength (RSSI), network throughput, packet delay, mesh routing recovery time and energy consumption in an indoor environment. Two main groups of network scenarios have been evaluated: (i) direct transmissions between the coordinator and the remote nodes, and (ii) transmissions with routers which relay the packet between the coordinator and the remote nodes. The wireless sensor node hardware designed for this experimentation consists of ZigBee (XBee S2 with 2mW wire antenna) wireless communication module from Digi International. X-CTU software is utilized for configuring and testing the ZigBee module of each sensor node. After configuration, the entire network is simulated in real time using Docklight V2.0 software. The results of this study are useful for building Wireless Home Area Network (WHAN) using the ZigBee where there...

This paper presents a low cost and flexible home control and monitoring system using an embedded ... more This paper presents a low cost and flexible home control and monitoring system using an embedded micro-web server, with IP connectivity for accessing and controlling devices and appliances remotely using Android based Smart phone app. The proposed system does not require a dedicated server PC with respect to similar systems and offers a novel communication protocol to monitor and control the home environment with more than just the switching functionality.

본 연구는 비감사서비스제공이 이익의 가치관련성에 영향을 미치는지, 그리고 그러한 영향이 기업지배구조에 따라 차이가 나는지를 분석하고자 하였다. 이를 위해 외부감사인에 의한 비... more 본 연구는 비감사서비스제공이 이익의 가치관련성에 영향을 미치는지, 그리고 그러한 영향이 기업지배구조에 따라 차이가 나는지를 분석하고자 하였다. 이를 위해 외부감사인에 의한 비감사서비스의 제공은 재무보고의 신뢰성에 대한 투자자의 인식에 부정적으로 영향을 미칠 것이며, 이러한 부정적 영향이 기업지배구조수준에 따라 완화 또는 강화될 것이라는 가설을 수립하였다. 기업지배구조 변수로는 이사회, 감사인, 소유구조를 고려하여 이사회 관련변수로 사외이사비율과 감사위원회설치여부, 감사인 관련변수로는 감사품질, 소유구조 관련변수로 대주주지분율을 사용하였다. 본 연구의 실증분석결과는 다음과 같다. 비감사서비스와 이익의 가치관련성 사이에는 유의한 음의 관련성이 있으며 이러한 음의 관계가 Big 4 감사인에 의해 감사받는 기업과 대주주지분율이 낮은 기업에 대해서는 약화되었으며 사외이사비율이 높은 기업과 감사위원회 설치기업에서는 그 유의성을 확인할 수 없었다. 따라서 비감사서비스가 비록 이익의 가치관련성을 감소시키더라도 몇 가지 주요한 기업지배구조는 이러한 영향을 완화시킬 수 있음을 알 수 있었다.

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

2017 IEEE 42nd Conference on Local Computer Networks Workshops (LCN Workshops), 2017

As a step toward sustainable wireless sensing, we present a proof of concept system that uses a P... more As a step toward sustainable wireless sensing, we present a proof of concept system that uses a Plant Microbial Fuel Cells (PMFC) as a power source. To match the very low power production capabilities of the PMFC, we couple it with an ultra-low power wake-up receiver used as a trigger for sampling and transmission of the sensed value. We demonstrate that this combination, with a new, receiver initiated MAC-level communication protocol, results in a sustainable system for reasonable data rates, shown to be 30s in our laboratory setting. This work offers the first steps toward large-scale wireless sensor networks in applications where the sensors are surrounded by living plants that can provide a green and perpetual power supply.

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

Sensors, 2018

Energy efficiency is crucial in the design of battery-powered end devices, such as smart sensors ... more Energy efficiency is crucial in the design of battery-powered end devices, such as smart sensors for the Internet of Things applications. Wireless communication between these distributed smart devices consumes significant energy, and even more when data need to reach several kilometers in distance. Low-power and long-range communication technologies such as LoRaWAN are becoming popular in IoT applications. However, LoRaWAN has drawbacks in terms of (i) data latency; (ii) limited control over the end devices by the gateway; and (iii) high rate of packet collisions in a dense network. To overcome these drawbacks, we present an energy-efficient network architecture and a high-efficiency on-demand time-division multiple access (TDMA) communication protocol for IoT improving both the energy efficiency and the latency of standard LoRa networks. We combine the capabilities of short-range wake-up radios to achieve ultra-low power states and asynchronous communication together with the long-...

IEEE Communications Surveys & Tutorials, 2017

Technology is a never ending process. To be able to design a product using the current technology... more Technology is a never ending process. To be able to design a product using the current technology that will be beneficial to the lives of others is a huge contribution to the community. This paper presents the design and implementation of Wireless Sensor tags which allows monitoring from anywhere with Internet access such as status of objects (open/close), movement and temperature of tagged items in your home or office. The tags can be set up to beep, once triggered through an Android or iOS app. Owners can receive alerts, push emails, read tweets through the app, once it monitors any changes in movement and temperature of tagged items. Keywords – Wireless sensor tags, ethernet tag manager, cloud based web service.

international conference on embedded wireless systems and networks, Feb 20, 2017

ArXiv, 2018

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

2017 IEEE 42nd Conference on Local Computer Networks Workshops (LCN Workshops), 2017

2018 14th International Conference on Wireless and Mobile Computing, Networking and Communications (WiMob), 2018

Sensors, 2018

IEEE Communications Surveys & Tutorials, 2017

Currently I am working on Human Activity & Context Recognition Using Smart Phone Sensors what I l... more Currently I am working on Human Activity & Context Recognition Using Smart Phone Sensors what I like to call, ubiquitous machine learning. The big question that motivates my work and studies is:

" What could we learn if we had access to all of the data collected by all of the electronic devices that every person on earth interacts with on a daily basis?"