Processing missing power data in wireless sensor networks

Izgledi za primjenom bežičnih senzorskih mreža - wireless sensor networks (WSN) vrlo su veliki zbog njihovih karakteristika – praktičnosti, niske cijene, točnosti. Moguće ih je primijeniti u mnogim područjima kao što su poslovanje, inteligentni kućni uređaji, industrija. Smatra ih se jednom od najutjecajnijih tehnologija danas. Električna energija se ne odnosi samo na zaradu za život pojedinaca već i na nacionalnu sigurnost. Trenutno je razvoj energetske industrije stigao do uskog grla. Jedna od metoda za razbijanje uskog grla u razvoju energetike je kombiniranje bežičnih senzorskih mreža s elektroindustrijom i izgradnja inteligentne mreže. Zbog raznih se razloga mogu izgubiti podaci koje generiraju bežične senzorske mreže i ti će nestali podaci imati veliki utjecaj na pronalaženje podataka o energiji i izgradnju inteligentne mreže. Podaci o energiji koje generiraju bežične senzorske mreže imaju i temporalnost i prostornost. U ovom radu predlažemo fuzijski algoritam koji se bavi podacima koji nedostaju u bežičnim senzorskim mrežama. Eksperimentalni podaci pokazuju da se predloženim algoritmom mogu učinkovito procijeniti podaci o energiji koji nedostaju u bežičnim senzorskim mrežama.The application prospects of wireless sensor networks (WSN) are very broad due to their characteristics of convenience, low cost, accuracy. Wireless sensor networks have potential applications in many fields, such as business, smart home appliances, industry. Wireless sensor networks are considered to be one of the most influential technologies today. The power industry is not only related to the livelihood of individuals, but also to national security. At present, the development of the power industry has reached a bottleneck. One of the methods to break through the bottleneck of the development of the electric power industry is by combining the wireless sensor networks with the electric power industry and building a smart grid. Due to various reasons, the data generated by the wireless sensor networks may be lost, and the missing data will have a great impact on the detection of power data and the construction of the smart grid. The power data generated by the wireless sensor networks has both temporality and spatiality. In this paper, we propose a fusion algorithm to deal with the missing data in wireless sensor networks. Experimental results show that the proposed algorithm can effectively estimate the missing power data in wireless sensor networks

Self-organising smart grid architectures for cyber-security

PhD ThesisCurrent conventional power systems consist of large-scale centralised generation and unidirectional power flow from generation to demand. This vision for power system design is being challenged by the need to satisfy the energy trilemma, as the system is required to be sustainable, available and secure. Emerging technologies are restructuring the power system; the addition of distributed generation, energy storage and active participation of customers are changing the roles and requirements of the distribution network. Increased controllability and monitoring requirements combined with an increase in controllable technologies has played a pivotal role in the transition towards smart grids. The smart grid concept features a large amount of sensing and monitoring equipment sharing large volumes of information. This increased reliance on the ICT infrastructure, raises the importance of cyber-security due to the number of vulnerabilities which can be exploited by an adversary. The aim of this research was to address the issue of cyber-security within a smart grid context through the application of self-organising communication architectures. The work examined the relevance and potential for self-organisation when performing voltage control in the presence of a denial of service attack event. The devised self-organising architecture used techniques adapted from a range of research domains including underwater sensor networks, wireless communications and smart-vehicle tracking applications. These components were redesigned for a smart grid application and supported by the development of a fuzzy based decision making engine. A multi-agent system was selected as the source platform for delivering the self-organising architecture The application of self-organisation for cyber-security within a smart grid context is a novel research area and one which presents a wide range of potential benefits for a future power system. The results indicated that the developed self-organising architecture was able to avoid control deterioration during an attack event involving up to 24% of the customer population. Furthermore, the system also reduces the communication load on the agents involved in the architecture and demonstrated wider reaching benefits beyond performing voltage control

Towards More Reliable MAC and PHY Layer Designs for High QoS Achievements for Safety Messaging in DSRC Systems

Broadcast communications are widely proposed for safety messaging. In the case of highway vehicular networks and constantly communicating safety messages inevitably cause the well-known hidden terminal problem. Three existing leading repetition-based broadcasting protocols have shown to meet the reliability and delay requirements for Dedicated Short Range Communications (DSRC) safety systems. We propose a quantitative model to evaluate the quality of service (QoS) of DSRC systems using these three leading repetition-based protocols under hidden terminals and highway scenarios. The performance of our model is analyzed by means of probability of success and delay performances. We also present three new Medium Access Control (MAC) layer design protocols for safety messaging applications. The main protocol we introduce is known as Passive Cooperative Collision Warning (PCCW) protocol for repetition based vehicular safety message reception reliability improvement in DSRC. The PCCW protocol and jointly proposed Enhanced-PCCW (EPCCW) and emergency-PCCW (ePCCW) protocols variants can work on top of existing repetition protocols for serving as a passive collision warning mechanism in the MAC Layer. A full analytical derivation of the relative reliability and delay performances for all three PCCW, EPCCW and ePCCW protocols are provided, serving as intuitive performance evaluators. EPCCW employs the physical (PHY) layer to create sub-slots for the purpose of further increasing reliability by both avoiding and minimizing probability of collision at slots that would nominally fail. Analytical and simulation results of PCCW and EPCCW agree, and show a significant reduction in message failure rate versus the leading repetition protocols, especially under high collision scenarios up to 40% at optimal, and 80% at higher repetitions. Additionally, an improvement in average timeslots delay is observed, which facilitates improved vehicular safety messaging. ePCCW is particularly useful for emergency vehicle (EV) communications. This enhancement makes meeting stringent quality of service (QoS) requirements particularly prevalent in safety applications of DSRC systems. ePCCW show up to 77% reliability improvement relative to a leading alternative is realized. Additionally, the proposed system is shown to have a decreased average timeslots delay that is well within acceptable delay threshold, and provides the best reliability in its class, which is key to safety messaging. In all our simulation results, we use our accurate Orthogonal Frequency Division (OFDM) MAC and physical (PHY) layer designs. The PHY layer simulator is a new object-oriented simulation environment, and is achieved using high-level design, parallelism and usability for the simulation environment. A high-level design and GUI layouts of the proposed simulator is shown in details. This can serve as a learning/research tool for students or practiced professionals to investigate particular designs. In addition, we provide a simple technique to implement simulation partitioning for increased parallel performance of reconfigurable object-oriented OFDM simulators. This simple technique applies to scenarios where there is disproportionate simulation duration between different OFDM configurations. It is shown to decrease total simulation time considerably. Additionally, we present a study on different demapping schemes at the PHY level. We propose the use of a linear demapper over a recently proposed non-linear demapper. The study is also presented under different decoding schemes of DSRC receivers. We also propose the use of equalization concepts in frequency domain that exploit the frequency domain channel matrix to combat inter-carrier interference (ICI) instead of inter-symbol interference (ISI) in DSRC systems. It is shown that the DSRC system with the frequency-domain equalization scheme achieves a considerable performance enhancement compared to both the conventional and the Viterbi-aided channel estimation schemes that try to combat ISI in terms of both Packet Error Rate (PER) and Bit Error Rate (BER) at relatively high and low velocities