An approach to understand network challenges of wireless sensor network in real-world environments

The demand for large-scale sensing capabilities and scalable communication networks to monitor and control entities within smart buildings have fuelled the exponential growth in Wireless Sensor Network (WSN). WSN proves to be an attractive enabler because of its accurate sensing, low installation cost and flexibility in sensor placement. While WSN offers numerous benefits, it has yet to realise its full potential due to its susceptibility to network challenges in the environment that it is deployed. Particularly, spatial challenges in the indoor environment are known to degrade WSN communication reliability and have led to poor estimations of link quality. Existing WSN solutions often generalise all link failures and tackle them as a single entity. However, under the persistent influence of spatial challenges, failing to provide precise solutions may cause further link failures and higher energy consumption of battery-powered devices. Therefore, it is crucial to identify the causes of spatial- related link failures in order to improve WSN communication reliability. This thesis investigates WSN link failures under the influence of spatial challenges in real-world indoor environments. Novel and effective strategies are developed to evaluate the WSN communication reliability. By distinguishing between spatial challenges such as a poorly deployed environment and human movements, solutions are devised to reduce link failures and improve the lifespans of energy constraint WSN nodes. In this thesis, WSN test beds using proprietary wireless sensor nodes are developed and deployed in both controlled and uncontrolled office environments. These test beds provide diverse platforms for investigation into WSN link quality. In addition, a new data extraction feature called Network Instrumentation (NI) is developed and implemented onto the communication stacks of wireless sensor nodes to collect ZigBee PRO parameters that are under the influence of environmental dynamics. To understand the relationships between WSN and Wi-Fi devices communications, an investigation on frequency spectrum sharing is conducted between IEEE 802.15.4 and IEEE 802.11 bgn standards. It is discovered that the transmission failure of WSN nodes under persistent Wi-Fi interference is largely due to channel access failure rather than corrupted packets. The findings conclude that both technologies can co- exist as long as there is sufficient frequency spacing between Wi-Fi and WSN communication and adequate operating distance between the WSN nodes, and between the WSN nodes and the Wi-Fi interference source. Adaptive Network-based Fuzzy Inference System (ANFIS) models are developed to predict spatial challenges in an indoor environment. These challenges are namely, “no failure”, “failure due to poorly deployed environment” and “failure due to human movement”. A comparison of models has found that the best-produced model represents the properties of signal strength, channel fluctuations, and communication success rates. It is recognised that the interpretability of ANFIS models have reduced due to the “curse of dimensionality”. Hence, Non-Dominated Sorting Genetic Algorithm (NSGA-II) technique is implemented to reduce the complexity of these ANFIS models. This is followed by a Fuzzy rule sensitivity analysis, where the impacts of Fuzzy rules on model accuracy are found to be dependent on factors such as communication range and controlled or uncontrolled environment. Long-term WSN routing stability is measured, taking into account the adaptability and robustness of routing paths in the real-world environments. It is found that routing stability is subjected to the implemented routing protocol, deployed environment and routing options available. More importantly, the probability of link failures can be as high as 29.9% when a next hop’s usage rate falls less than 10%. This suggests that a less dominant next hop is subjected to more link failures and is short-lived. Overall, this thesis brings together diverse WSN test beds in real-world indoor environments and a new data extraction platform to extract link quality parameters from ZigBee PRO stack for a representative assessment of WSN link quality. This produces realistic perspectives of the interactions between WSN communication reliability and the environmental dynamics, particularly spatial challenges. The outcomes of this work include an in-depth system level understanding of real-world deployed applications and an insightful measure of large-scale WSN communication performance. These findings can be used as building blocks for a reliable and sustainable network architecture built on top of resource–constrained WSN

Long-term routing stability of wireless sensor networks in a real-world environment

The reliability of a wireless sensor network (WSN) is often assessed on node-to-node communication performance through link characterization. Long-term routing stability is an aspect of a WSN that is often overlooked in routing protocol implementations. In this paper, we investigate the routing stability of ZigBee PRO implemented WSN nodes that are deployed in a real-world environment. Frequent changes in next hops along routing paths between source and destination nodes can result in an increase in undesired energy consumption of the WSN. Hence, the relative routing path usage count, usage rate of unique next hop and switching frequency count are proposed as routing stability indicators. Our findings show that routing stability is subjected to not only the quality of a link but also to the implemented routing protocols, deployed environment and routing options available. More importantly, next hops with low usage rates are shown to experience a higher probability of disconnection from the Neighbor Table of respective source nodes, causing them to be short-lived. The need to avoid these links shows the importance of evaluating routing stability and identifying network bottlenecks

CRIMINALIZING PRIMARY COPYRIGHT INFRINGEMENT IN SINGAPORE: WHO ARE THE REAL ONLINE CULPRITS

It is axiomatic in the international copyright arena for the law to impose criminal liability on secondary acts of copyright infringement. Such acts of infringement (which may also attract civil liability) typically entail the commercial exploitation of infringing copies of copyright material by unlicensed vendors. Take, for example, the ubiquitous street vendor in Bangkok’s hugely-popular Patpong district who, on a daily basis, hawks pirated CDs and DVDs to throngs of foreign tourists. Although street scenes such as these are fairly commonplace and representative of the livelihoods of numerous other unlicensed vendors the world over, the law clearly frowns upon such practices and, for some time now, has imposed penal sanctions on these secondary infringers of copyright.1 The use of the criminal law under such circumstances to aid in the effective enforcement of intellectual property rights is understandable, because the sale of each unauthorised copy of music, film or software will, correspondingly, deprive the relevant copyright owner of the economic benefits of a legitimate transaction. Yet the fact remains that many of these so-called copyright pirates have continued to operate under the present legal environment simply because of high consumer demand; there is, after all, a sizeable global market for illegitimate products of intellectual property. The irony, of course, is this: that whilst it is a criminal offence to trade in illegitimate copies of copyright material, it is – at least under copyright law – not a crime nor an actionable civil wrong to purchase or acquire such copies for private and domestic use.2 However, in light of the rapid advancements in computer, digital and Internet technologies, consumers and other end-users have begun to take things into their own hands. Instead of purchasing illegitimate copies of copyright material from the street vendor, they now discover that it is far more efficient and cost-effective to acquire digital copies for themselves in the privacy of their own rooms from certain Internet websites or through peer-to-peer (P2P) file-sharing networks. They may further decide to share these digital copies with others in the Internet or P2P file-sharing community. In the process, however, they inadvertently expose themselves to civil action for having committed primary acts of copyright infringement, and, in Singapore at least, they may also face criminal prosecution if primary infringers like themselves are found guilty of wilful infringements of copyright. Against this backdrop, the authors will, in this paper, examine the newly introduced criminal provisions in Singapore’s copyright legislation which target primary acts of copyright infringement and will consider, in particular, the consequences of prosecuting offenders pursuant to these provisions in the context of a number of hypothetical scenarios involving acts of infringement committed on the Internet. These Internet-based scenarios are particularly relevant and timely in the present discussion in light of recent reports in the local media concerning – (1) the various measures taken by the Intellectual Property Office of Singapore (and other local agencies) to encourage all companies and businesses to use legal or licensed software in the conduct of their day-to-day business; as well as (2) the recent arrest and prosecution of two individuals in Singapore for allegedly distributing unauthorised music files via an Internet chat program.3 This paper therefore aims to offer an academic perspective of the various types of online activity which, in the authors’ view, will likely attract criminal liability under the new provisions (as well as those which ought not to)

Quality of Assessment in Connected Vehicles

In recent years, there has been a huge interest in Machine-to-Machine connectivity under the umbrella of Internet of Things (IoT). With the UK Government looking to trial autonomous (driverless) cars this year, connected vehicles will play a key part in improving and managing existing road safety and congestion, leading to a new generation of intelligent transport systems. This is also well aligned to the current initiatives by the automotive industry to improve the driver’s experience on-board. However, the wireless channels most suitable for this application have not been standardized. In this paper, we review the wireless channels suitable for vehicle-2-vehicle (V2V) and Vehicle–to-x (V2x) connectivity. We further present preliminary analysis on the factors that impact the Quality of Service (QoS) of connected vehicles. We use the open access GEMV2 data to carry out Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) on the link quality and found that both line of sight and non line of sight has a significant impact on the link quality. The work presented here will help in the development of connected vehicle network (CVN) prediction model and control for V2V and V2x connectivity. It will further contribute towards unfolding and testing key research questions in the context of connected vehicles which may otherwise be overlooked

Quality of Assessment in Connected Vehicles

In recent years, there has been a huge interest in Machine-to-Machine connectivity under the umbrella of Internet of Things (IoT). With the UK Government looking to trial autonomous (driverless) cars this year, connected vehicles will play a key part in improving and managing existing road safety and congestion, leading to a new generation of intelligent transport systems. This is also well aligned to the current initiatives by the automotive industry to improve the driver’s experience on-board. However, the wireless channels most suitable for this application have not been standardized. In this paper, we review the wireless channels suitable for vehicle-2-vehicle (V2V) and Vehicle–to-x (V2x) connectivity. We further present preliminary analysis on the factors that impact the Quality of Service (QoS) of connected vehicles. We use the open access GEMV2 data to carry out Analysis of Variance (ANOVA) and Principal Component Analysis (PCA) on the link quality and found that both line of sight and non line of sight has a significant impact on the link quality. The work presented here will help in the development of connected vehicle network (CVN) prediction model and control for V2V and V2x connectivity. It will further contribute towards unfolding and testing key research questions in the context of connected vehicles which may otherwise be overlooked

Predicting Types of Failures in Wireless Sensor Networks Using an Adaptive Neuro-fuzzy Inference System

In this paper, Adaptive Neuro-Fuzzy Interference System (ANFIS) technique is used to develop models to predict two conditions commonly found in a Wireless Sensor Network's deployment; these conditions are failure due to (i) poorly deployed environment and (ii) human movements. ANFIS models are trained using parameters obtained from actual ZigBee PRO nodes' Neighbour Table experimented under the influence of associated network challenges. These parameters are Mean RSSI, Standard Deviation RSSI, Average Coefficient of Variation RSSI and Neighbour Table Connectivity. The individual and combined effects of parameters are investigated in-depth. Results showed the mean RSSI is a critical parameter and the combination of mean RSSI, ACV RSSI and NTC produced the best prediction results (~92%) for all ANFIS models

Growth performance of brown-golden marine microalga, Isochrysis sp., cultivated in alternative algal culture media

The present study aimed to evaluate the suitability of introduced algal culture media as an alternative to the general enriched seawater media in the laboratory cultivation of Isochrysis sp., a marine microalga commonly cultivated for aquaculture purposes. Isochrysis sp. was established into culture in three replications using three experimental algal culture media (Walne’s medium as a control, China-contributed culture medium (CCM) and CCM supplemented with vitamins (CCM + Vit)). The experiment was performed with a continuous illumination for a period of seven days at 25±1°C. The effect of introduced algal culture media (CCM and CCM + Vit) on the growth performance of Isochrysis sp. was highlighted. CCM demonstrated promising results for the cultivation of Isochrysis sp. A maximum cell density of 9.16×106 ± 5.40×105 cells mL-1, which corresponded to an instantaneous growth rate (r) of 0.21 cell day-1 and a doubling time (T2) of 3.29 days, was observed in Isochrysis sp. cultivated in CCM. In view of its potential and reduced preparation labour, CCM may be recommended as an alternative to the general enriched seawater media in the cultivation of Isochrysis sp. in laboratories with basic facility as well as small- and medium-scale aquaculture hatcheries

Length-weight relationship and relative condition factor of pearl oyster, Pinctada fucata martensii, cultured in the Tieshangang Bay of the Beibu Gulf, Guangxi Province, China

Tieshangang Bay in the Beibu Gulf, Guangxi of China, is a strategic location for pearl farming. Although water pollution has been reported in this bay but the general health of the pearl oyster, Pinctada fucata martensii,farmed there has never been assessed. The present study examined the condition of P. fucata martensii farmed in the Tieshangang Bay by analyzing its length-weight relationship (LWR) and relative condition factor (RCF). A total of 111 specimens were sampled for measuring their shell height and total weight for determining the LWR and RCF. The coefficient of correlation of the LWR was high (R2= 0.93), significant at 0.01 level. Negative allometric growth (b= 2.7048) was observed. However, P.fucata martensiiachieved the expected growth in terms of weight, as determined through the RCF (mean 1.13). Negative allometric growth is commonly reported on the wild Pinctadaspp. collected from different regions. Apparently, the water pollution in the Tieshangang Bay did not compromise the general health of the pearl oyster cultured there. Nevertheless, further study on the farm’s surrounding water quality and plankton availability is necessary to investigate the interaction between the growth of the oyster and its culture environment. In conclusion, the P. fucata martensiifarmed in the Tieshangang Bay was considered healthy and the bay is still suitable for pearl oyster farming

Oceans and COVID-19: perspectives, reflections, recovery and regulatory frameworks

COVID-19 pandemic has created an unprecedented public health crisis, taken about 1.4 million lives so far, infected almost 70 million people around the world, battered the global economy and paralyzed the normal activity. This situation is evolving so rapidly that the data on numbers of infections and deaths are changing daily and the economic impacts are difficult to evaluate at this stage and probably will not be exactly known in the near future. It is important to determine the genesis of the outbreak to understand the root causes of COVID-19 and to prevent such pandemics from occurring in the future. It is believed that the virus originated in a seafood market in Wuhan (China) that was also trading in wildlife for human consumption. Such practices are associated with the habitat degradation and biodiversity loss, leading to an imbalance of the natural ecosystems. The zoonotic spillover of this infectious outbreak is a reflection of the impairment of natural systems. Scientific and anecdotal evidences demonstrate the significance of marine critical habitats in combating and containing human diseases. There are many other ways in which the oceans can help in human health. In addition to providing an analysis of the COVID-19 outbreak, this paper also suggests knowledge-based and informed measures that need to be applied to prevent a repeat of such catastrophic events while highlighting the role of oceans in this context. Plans and strategies for recovering the global economy and ensuring its resilience will require incorporating nature-based solutions and ecosystem restoration. The sustainability of the ocean is a key consideration in the development of a framework for post-COVID-19 recovery and this aspect is the major focus of this paper