UNIVERSIT`
A DI PISA
DIPARTIMENTO DI INGEGNERIA DELL’INFORMAZIONE
Dottorato di Ricerca in Ingegneria dell’Informazione
Activity Report by the Student Mike Oluwatayo OJO - I,II,III year of the
PhD Program, cycle XXXI
Tutor(s): Prof. Stefano Giordano, Prof. Michele Pagano and Ing. D. Adami
1. Research Activity First Year
The research activity of the doctoral student Mike Oluwatayo OJO during the first year is primarily focused on three research areas: Scheduling in IEEE 802.15.4-2015 Time Slotted Channel Hopping (TSCH) Networks, Performance Evaluation of Energy Saving MAC Protocols in WSN Operating Systems and lastly Software Defined Networking in Internet of Things.
The first phase of my research work involved the study of IEEE 2015 TSCH. IEEE 802.15.4-2015 standard is one of the leading standards in the Internet of Things, which is the third revision of the IEEE 802.15.4 Standard for Low Rate Wireless Networks. Among the operating modes defined in this standard is Time-Slotted Channel Hopping (TSCH), which is a Medium Access Control (MAC) protocol for low-power and reliable networking solutions in Low-Power Lossy Networks (LLNs). IEEE 802.15.4-2015 TSCH brings high reliability and low power consumption to various industrial applications running in harsh environments. The initial concept of TSCH emerges from the proprietary Time Synchronized Mesh Protocol (TSMP) in 2006, and to ensure interoperability, the concept has been applied to other industrial standards such as WirelessHart (IEC62591), ISA100.11a (ICE 62734), and IEEE 802.15.4e, and then wrapped up in the IEEE 802.15.4-2015 standard in 2016.
Despite its relevance, the standard leaves out its scope in defining how the schedule is built, updated and maintained. This is an open issue that still needs to be addressed. My first year research activity focused on developing a novel scheduling algorithm in IEEE 802.15.4-2015 TSCH networks. The work fo-cused on scheduling in a centralized manner where the gateway makes time and frequency slot allocation. We formulated the scheduling problem as throughput maximizing and delay minimizing. For solving the throughput maximization scheduling problem, a polynomial time algorithm was introduced by adopting a graph theoretical approach, which introduced a tractable equivalent integer linear programming formula-tion. The combinatorial properties of the scheduling problem are addressed by providing an equivalent maximum weighted bipartite matching (MWBM) problem to reduce the computational complexity and also adopting the Hungarian algorithm in polynomial time. For the delay minimization problem, this is said to be a non-linear binary integer programming problem known to be NP-hard and can be solved using Branch-and bound algorithms.
The other research area focused on the study of Software Defined Networks (SDN) and Network Func-tion VirtualizaFunc-tion (NFV) evoluFunc-tion and how it can be applied to WSN and Internet of Things (IoT) in general. It has been proposed that both SDN and NFV will be a key enabler for the IoT. The idea is to limit the functionality embedded in deployed sensors, and provide virtualized functions such as security, intelligence, computation and storage to the devices. This would take advantage of the scalable distribu-tion capabilities of NFV as well as the configuradistribu-tion flexibility of SDN. We proposed a multi-layered IoT architecture involving SDN and NFV and illustrate how the proposed architecture is able to cope with
-some of the challenges in IoT such as scalability, mobility etc. However, during the first year period, there were questions and open research areas that needed to be investigated such as the management of big amounts of IoT-generated data and methods of studying efficient ways of transporting (big) data over such softwarized networks, and whether current cloud data management applications such as Hadoop would be able to support the real time requirements in such environments. Some other open research areas we studied and investigated on are on how to relocate various IoT functions from hardware appliances to virtual machines and make them connected or chained together; how to abstract IoT’s behaviours by SDN concept?
The last research area during my first year was about the study and investigation of the MAC protocols in wireless sensor networks. We focused on the most recent and well known open source operating systems in the research community such as RIOT OS, OpenWSN OS, Contiki OS etc. At first, we studied the duty cycle mechanisms, which is considered as one of the most essential technique among other energy conservation technique due to its flexibility of implementation that does not require special capabilities of sensor node platforms. We also studied various simulators and emulators used in WSN which is used in analyzing and validating practices prior to deploying sensing and computational devices in the real world. For example, we made comparison between the RDC protocols in Contiki OS using Zolertia Z1 board as our hardware and COOJA as the simulator. We also demonstrated the power/energy consumption of a WSN node (OpenMote-CC2538) with experimental evaluation using direct measurement finding out the network life-time in WSN which is an important performance metric.
Second Year
The research activity undertaken during the second year was an extension of the scheduling algorithms in IEEE 802.15.4-2015 TSCH networks. We focused on scheduling in IEEE 802.15.4-2015 TSCH networks from the energy efficiency perspective in a centralized manner where the gateway makes frequency alloca-tions and time slot assignments. In terms of the energy efficiency (EE), the network throughput modeling was introduced by calculating the link capacity and the total throughput for a slot frame. We also outlined the components of energy dissipation in a TSCH network: transmission, reception, idling and sleeping. These components are very relevant in wireless networks and multi-channel networks. We formulated the centralized assignment problem as an Energy Efficiency (EE) maximization problem. The formulated problem is a Nonlinear Programming (NLP), which is mostly known to be computationally hard to solve. Therefore, we sought for computationally easier solutions. At first, due to the nonlinearity of the problem formulation of the EE maximization problem and identified as a Concave Fractional Programming (CFP), we transformed the EE maximization problem into a tractable problem by decomposing the problem into an Integer Linear Programming (ILP) problem using Charnes Cooper Transformation (CCT) to provide the optimal solution as the upper bound for energy efficiency. Secondly, a polynomial time heuristic algo-rithm was introduced labeled Energy Efficient Scheduler (EES) that provided maximum energy efficiency in a frame. Next, another heuristic scheduler (referred to as VAM-HSA) based on Vogel’s Approximation Method (VAM) was introduced that addressed the pitfalls of the greedy allocation in the EES algorithm. In addition, we adopted the Genetic Algorithm (GA) framework for solving the throughput maximization problem.
Third Year
My research activity undertaken during the third year focused on Scheduling in IEEE 802.15.4 – 2015 TSCH Networks. This work was a follow-up of the 1st and the 2nd year activity report, where an integer programming scheduling problem was formulated for the throughput maximization in TSCH networks. In the third year, a polynomial time algorithm for the throughput maximization problem was proposed and we elaborated on certain special cases of this problem and explored their combinatorial properties. We introduced a novel auction-based heuristic algorithm to address the throughput maximization scheduling problem. A first-price sealed-bid auction was used as the auction mechanism, and a time complexity
-analysis of the algorithm was also provided. We proceeded to formulate a max-min fair scheduling problem that provided throughput fairness. It considered the throughput historical information of the nodes in the past and used this information in the current scheduling problem. A heuristic approach based on greedy algorithm was proposed to address the max-min fair scheduling problem and the time complexity analysis of the heuristic algorithm was also provided.
Ensuring high quality of service and reliability are the key essential requirements in industrial type applications. Routing is an essential way in realizing these requirements as it determines the reliability, lifetime, end-to-end delay of a network. SDN delivers a promising solution to Wireless sensor networks (WSN) in providing flexibility in network management decisions such as routing, scheduling, just to mention a few. On the other hand, IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) is considered as the standardized routing protocol for industrial-type applications. Due to the rapid technological growth in WSN, which increases its challenges, a need to provide a detailed performance evaluation of SDN and RPL is consequential. During my third year, we investigated on the performance of SDN and RPL by providing a performance analysis on real-hardware based experimental measurements using OpenMote-CC2538. We also investigated on different ways of achieving a Quality of Service for deterministic industrial-type applications. One of the ways we looked at was about packet replication and elimination. We also looked at how overhearing mechanism can enhance end-to-end reliability by taking advantage of the nature of a wireless medium.
Lastly, we also focused on the development of Internet of Things application for crop protection to prevent animal intrusions in the crop field. A repelling and a monitoring system was provided to prevent potential damages in Agriculture, both from wild animal attacks and weather conditions. The repelling device, based on ATSAMD21G18A microprocessor took care of the frequency production and the networking operations. To improve the energy efficiency of the device, we made use of a Passive Infrared Sensor (PIR) sensor, which activated the driver responsible for the ultrasound generation and as well as the networking communication only when an animal is detected. The sound produced by the device is 120dB in approx. 1m distance and in a wide band of 20kHz - 40kHz that allowed us to tune the device according to the animal that is desired to be repelled. To transmit, process and store the information retrieved by the device, we used a Proxy software that collected the activity of animals from the device and forwards it to the back-end system.
2. Formation Activity
1. Konstantin Samouylov, Yuliya Gaidamaka - RUDN University, Moscow, Russia, ”Mathematical Mod-eling issues in the Future Multiservice Networks”, 20 hours (5 credits)
2. CLI, “Academic Writing and Presentation Skills for Engineering PhD Students”, (4 credits).
3. IEEE COMSOC Summer School, 20th June – 23rd June, 2016. Trento, Italy. - 22 hours (5 credits). 4. PhD Summer School in Information Engineering “Technologies for Internet of Things”, Bressanone,
Italy. 22 hours (5 credits).
5. Kishor Trivedi, Duke University, “Reliability, Availability and Performance of Data Centers and Clouds”, 14 - 18 Marzo 2016, (5 credits).
6. M. Luise, L. Sanguinetti, Univ. Pisa: “Game Theory and Optimization in communications and Networking”, 1-4 Febbraio 2016, (4 credits).
7. PHD + 2016: “Valorizzazione della Ricerca, Innovazione, Spirito Imprenditoriale”, 35 hours (9 credits).
8. Gianpaolo Coro, CNR, “Signal Processing and Mining of Big Data: Biological Data as Case Study”, 20 hours (5 credits).
TOTAL CREDITS: 42
-3. Publications
Include the list of publications appeared in the I,II,III year of the PhD program, according the following format:
International Journals :
[J1 ] M.O. Ojo, S. Giordano, G. Procissi and I. Seitanidis: ”A Review of Low-end, Middle-end and High-end IoT Devices”, IEEE Access, November 2018.
[J2 ] M.O. Ojo, S. Giordano, D. Adami and M. Pagano: ”Throughput Maximizing and Fair Scheduling Algorithms in Industrial Internet of Things Networks”, IEEE Transactions of Industrial Informatics. September 2018.
International Conferences/Workshops with Peer Review :
[C1 ] E. Tsapardakis, M. Ojo, P. Chatzimisios and S. Giordano: ”Performance Evaluation of SDN and RPL in Wireless Sensor Networks”, In Global Information Infrastructure and Networking Symposium (GIIS), (pp. 1-5), IEEE, October 2018.
[C2 ] M.O. Ojo, S. Giordano, D. Adami and M. Pagano: ”A Novel Auction Based Scheduling Algorithm in Industrial Internet of Things Networks”, In International Conference on Computer Networks, (pp. 103-114), Springer, Cham, June 2018.
[C3 ] S. Giordano, I. Seitanidis, M. Ojo, D. Adami and F. Vignoli: ”IoT Solutions for Crop Protection against Wild Animal Attacks”, In 2018 IEEE International Conference on Environmental Engineering (EE), (pp. 1-5), IEEE, March 2018.
[C4 ] M. Ojo, S. Giordano, G. Portaluri and D. Adami: ”Throughput Maximization Scheduling Algorithm in TSCH Networks with Deadline Constraints. In Globecom Workshops (GC Wkshps), (pp. 1-6), IEEE, December 2017.
[C5 ] M. Ojo, S. Giordano, G. Portaluri, D. Adami and M. Pagano: ”An Energy Efficient Centralized Scheduling Scheme in TSCH Networks”, In Communications Workshops (ICC Workshops), 2017 IEEE International Conference on, (pp. 570-575), IEEE, May 2017.
[C6 ] M. Ojo, D. Adami and S. Giordano: ”A SDN-IoT Architecture with NFV Implementation” In Globecom Workshops (GC Wkshps), (pp. 1-6), IEEE, December 2016.
[C7 ] M. Ojo and S. Giordano: ”An Efficient Centralized Scheduling Algorithm in IEEE 802.15.4e TSCH networks”. In Standards for Communications and Networking (CSCN), 2016 IEEE Conference on, (pp. 1-6), IEEE, October 2016
[C8 ] M. Ojo, D. Adami and S. Giordano: ”Performance Evaluation of Energy Saving MAC Protocols in WSN Operating Systems”. In Performance Evaluation of Computer and Telecommunication Systems (SPECTS), 2016 International Symposium on, (pp. 1-7), IEEE, July 2016.
Others :
[O1 ] M. Ojo and S. Giordano: “Centralized Scheduling in TSCH Newtorks for Energy Efficiency”, Italian Networking Workshop, January 2017
