Automated System to Debug Under-performing Network Flows in Wide Area Networks

Locating the cause of performance losses in large high performance Wide Area Networks (WAN) is an extremely challenging problem. This is because WANs comprise several distributed sub-networks (Autonomous Networks), with their own independent network monitoring systems. Each individual monitoring system has limited or no access to network devices outside its own network. Moreover, conventional network monitoring systems are designed only to provide information about the health of individual network devices, and do not provide sufficient information to monitor endto- end performance – thus, adding severe overhead on debugging end-toend performance issues. In this thesis, an automated tool is designed that requires no special access to network devices and no special software installations on the network devices or end hosts. The system detects performance losses and locates the most likely problem nodes (routers/links) in the network. A key component of this system is the novel hybrid network monitoring/data collection system. The monitoring/data collection sub-system is designed to obtain the best of both active and passive monitoring techniques. Then, pattern analysis algorithms are designed. They locate the causes of performance loss using the data collected from above sub-system. This system is being tested on the GLORIAD (Global Ring Network for Advanced Application Development) network. One of the future goals is to in tegrate this system into the GLORIAD’s network monitoring tool set, to provide end-to-end network monitoring and problem mitigation capabilities

Performance evaluations of adaptive dynamic source routing protocol for mobile ad hoc network / Zuraida Abdullah Hani

Mobile Ad Hoc Network (MANET) is a collection of wireless mobile nodes forming a temporary network without the use of any existing network infrastructure or centralized administration. The topology of the network is dynamic and the changes are often unpredictable. Nodes in ad hoc network find the routes themselves; thus, routing poses a big challenge. Many routing protocol had been proposed in literature. Dynamic Source Routing (DSR) protocol which is an on demand base routing, seems to have good performance and more reliable in dynamic environment. However the routing overhead of DSR needs to be improved. To overcome the weakness, instead of improving the features in the protocol, active source is introduced. This active source is an independent module and does not change any existing aspect of the DSR module. In active source, active packet is deployed. This active packet roams around the network and collects network topology information in its cache. By checking all the contents in active packet when it passes through networks nodes, route cache of network nodes is updates. In this research, both DSR and active source are implemented and combined in OPNET simulation software. The results show the deployment of this active source reduces up to 49 percent routing overhead and reduces end-to- end delay until 20.5 percent. The frequent update of route cache in network nodes, make network nodes always ready with valid route. These contributions improve the routing overhead and end-to-end delay

Дослідження динаміки навантаженості рами двигуна коренезбиральної машини КС-6Б

This article studies five Swedish cities, their membership in international city networks, the different motivations for such membership, and their administrations’ expected and perceived benefits. Particular focus is put on sustainability, environmental technology, and municipal companies as potential beneficiaries of such network membership. This study is motivated by the fact that city networks can potentially contribute to global sustainability goals by accelerating the diffusion of innovations, giving members access to bidirectional information flows, improving the user-producer relationship, and providing legitimacy in the potential recipient regimes. The study relies on a documentation review, the collection of data from the websites of the studied cities and numerous international city networks, and interviews with city officials responsible for international city networks. It was found that four of the five studied cities are active members of international networks for sustainability, but also that there are large gaps between the two largest cities and the rest when it comes to the number of memberships and the geographical outreach they have through the networks they belong to. Some city officials claim that it is easier to be active in national networks than in international networks, due to time requirements and coordination among so many members. However, city officials see benefits for their municipal companies when they are members of international networks, and these companies are usually independent when it comes to choosing and administering their memberships. It was found that it is difficult to measure direct benefits from network membership, and link improvements in the studied cities to participation in a particular network (with the exception of groups created for a specific infrastructure project, reported as “networks” by the administrations). In addition, there is no apparent direct correlation between membership and diffusion of environmental solutions from municipal companies. However, the administrations expect indirect benefits such as gaining legitimacy and access to milieus where they can share information and best practices, which could lead to the improvement of both local and global environmental conditions.Funding agencies: Swedish Governmental Agency for Innovation Systems (VINNOVA); Swedish Energy Agency; Tekniska Verken AB</p

Handling Emergent Conflicts in Adaptable Rule-based Sensor Networks

This thesis presents a study into conflicts that emerge amongst sensor device rules when such devices are formed into networks. It describes conflicting patterns of communication and computation that can disturb the monitoring of subjects, and lower the quality of service. Such conflicts can negatively affect the lifetimes of the devices and cause incorrect information to be reported. A novel approach to detecting and resolving conflicts is presented. The approach is considered within the context of home-based psychiatric Ambulatory Assessment (AA). Rules are considered that can be used to control the behaviours of devices in a sensor network for AA. The research provides examples of rule conflict that can be found for AA sensor networks. Sensor networks and AA are active areas of research and many questions remain open regarding collaboration amongst collections of heterogeneous devices to collect data, process information in-network, and report personalised findings. This thesis presents an investigation into reliable rule-based service provisioning for a variety of stakeholders, including care providers, patients and technicians. It contributes a collection of rules for controlling AA sensor networks. This research makes a number of contributions to the field of rule-based sensor networks, including areas of knowledge representation, heterogeneous device support, system personalisation, and in particular, system reliability. This thesis provides evidence to support the conclusion that conflicts can be detected and resolved in adaptable rule-based sensor networks

Ants Sleep, Plants do not: The Variation in Species’ Activity Influences the Topology of Interaction Networks

The emergence of graph theory allowed using the complex network approach to aggregate detailed information about interactions between species. Although the use of the complex network approach has improved the understanding about community structuring, few aspects such as the temporal variation in the species’ activity pattern in the networks’ topology were explored so far. The current study used the ecological network approach to investigate ants interacting in the extrafloral nectary (EFN) of plants in order to test the hypothesis that the temporal variation in the foraging behavior of these animals affects the networks’ topology. In order to assess the temporal effect on the interaction networks, 24-hour collections divided in two 12-hour shifts (day and night) were performed in 20 plots, thus totaling 288 collection hours over 6 months. The ant-plant interaction networks presented similarity among the topological metrics assessed throughout the day. Different ant species presented distinct foraging times. Thus, two modules referring to the day and night shifts emerged from the network and presented specific species at each foraging shift. On the other hand, the plants kept on providing the resource (active EFNs) throughout the day. The results found in the current study have shown that ecological networks keep their structures constant; however, the ecological processes ruling these networks can better respond to the effects caused, for example, by the temporal variation in species’ activity. Therefore, it is worth always taking into consideration the importance of ecological processes at the time to analyze interactions in the nature

Actively learning a Bayesian matrix fusion model with deep side information

High-dimensional deep neural network representations of images and concepts can be aligned to predict human annotations of diverse stimuli. However, such alignment requires the costly collection of behavioral responses, such that, in practice, the deep-feature spaces are only ever sparsely sampled. Here, we propose an active learning approach to adaptively sampling experimental stimuli to efficiently learn a Bayesian matrix factorization model with deep side information. We observe a significant efficiency gain over a passive baseline. Furthermore, with a sequential batched sampling strategy, the algorithm is applicable not only to small datasets collected from traditional laboratory experiments but also to settings where large-scale crowdsourced data collection is needed to accurately align the high-dimensional deep feature representations derived from pre-trained networks

Identity-based access control for pro-active message's DTN

Pro-active message's delay tolerant networks (DTNs) are based on the usage of mobile code to obtain messages that contain their own routing code. This architecture allows applications to use the same network in different ways. The keystone of this type of heterogeneous network is a collection of contextual and application-related information that it is stored in every node and accessed by the messages' routing code. Access to that information must be protected in order to make the whole architecture feasible; the operation of the network has to be secure, and attacks of information poisoning have to be avoided. We propose an identity-based access control system for pro-active message's DTN based on tools that are available in DTN networks, like symmetric key encryption and hashes. Our system grants confidentiality and integrity to the contextual information and solves the question of messages needing to use distributed information stored in nodes to route properly. The proof of concept of identity-based access control in a certain kind of application demonstrates the feasibility of the proposal. The comparison between our proposal and other access control systems shows that identity-based access control is the only system that fits well with the special characteristics of pro-active message's DTN. Copyright © 2016 John Wiley & Sons, Ltd

Stealthy attacks and defense strategies in competing sensor networks

The fundamental objective of sensor networks underpinning a variety of applications is the collection of reliable information from the surrounding environment. The correctness of the collected data is especially important in applications involving societal welfare and safety, in which the acquired information may be utilized by end-users for decision-making. The distributed nature of sensor networks and their deployment in unattended and potentially hostile environments, however, renders this collection task challenging for both scalar and visual data. In this work we propose and address the twin problem of carrying out and defending against a stealthy attack on the information gathered by a sensor network at the physical sensing layer as perpetrated by a competing hostile network. A stealthy attack in this context is an intelligent attempt to disinform a sensor network in a manner that mitigates attack discovery. In comparison with previous sensor network security studies, we explicitly model the attack scenario as an active competition between two networks where difficulties arise from the pervasive nature of the attack, the possibility of tampering during data acquisition prior to encryption, and the lack of prior knowledge regarding the characteristics of the attack. We examine the problem from the perspective of both the hostile and the legitimate network. The interaction between the networks is modeled as a game where a stealth utility is derived and shown to be consistent for both players in the case of stealthy direct attacks and stealthy cross attacks. Based on the stealth utility, the optimal attack and defense strategies are obtained for each network. For the legitimate network, minimization of the attacker’s stealth results in the possibility of attack detection through established paradigms and the ability to mitigate the power of the attack. For the hostile network, maximization of the stealth utility translates into the optimal attack avoidance. This attack avoidance does not require active communication among the hostile nodes but rather relies on a level of coordination which we quantify. We demonstrate the significance and effectiveness of the solution for sensor networks acquiring scalar and multidimensional data such as surveillance sequences and relate the results to existing image sensor networks. Finally we discuss the implications of these results for achieving secure event acquisition in unattended environments

Understanding the role of contrasting urban contexts in healthy aging: an international cohort study using wearable sensor devices (the CURHA study protocol).

BACKGROUND: Given the challenges of aging populations, calls have been issued for more sustainable urban re-development and implementation of local solutions to address global environmental and healthy aging issues. However, few studies have considered older adults' daily mobility to better understand how local built and social environments may contribute to healthy aging. Meanwhile, wearable sensors and interactive map-based applications offer novel means for gathering information on people's mobility, levels of physical activity, or social network structure. Combining such data with classical questionnaires on well-being, physical activity, perceived environments and qualitative assessment of experience of places opens new opportunities to assess the complex interplay between individuals and environments. In line with current gaps and novel analytical capabilities, this research proposes an international research agenda to collect and analyse detailed data on daily mobility, social networks and health outcomes among older adults using interactive web-based questionnaires and wearable sensors. METHODS/DESIGN: Our study resorts to a battery of innovative data collection methods including use of a novel multisensor device for collection of location and physical activity, interactive map-based questionnaires on regular destinations and social networks, and qualitative assessment of experience of places. This rich data will allow advanced quantitative and qualitative analyses in the aim to disentangle the complex people-environment interactions linking urban local contexts to healthy aging, with a focus on active living, social networks and participation, and well-being. DISCUSSION: This project will generate evidence about what characteristics of urban environments relate to active mobility, social participation, and well-being, three important dimensions of healthy aging. It also sets the basis for an international research agenda on built environment and healthy aging based on a shared and comprehensive data collection protocol