Rapidly evolving wireless technologies enable devices to directly exchange information without infrastructural support. In these device-to-device (D2D) communication scenarios, it is often difficult to setup cryptographic keys to initialize the secure communication, especially when the D2D connections are mobile and dynamic. This paper proposes an application layer solution scheme to bootstrap secure communications using the inherent randomness in the wireless transmissions. The proposed scheme is lightweight, easy to deploy and compatible with many physical layer wireless technologies. This paper contains security analysis to the scheme and conducts experiments to demonstrate its practicality.

Temperature sensing and control systems are widely used in the closed-loop control of critical processes such as maintaining the thermal stability of patients, or in alarm systems for detecting temperature-related hazards. However, the security of these systems has yet to be completely explored, leaving potential attack surfaces that can be exploited to take control over critical systems.

Most recommendation algorithms mainly make use of user history interactions in the model, while these methods often suffer from the cold-start problem (user/item has no history information). On the other sides, content features help on cold-start scenarios for modeling new users or items. So it is essential to utilize content features to enhance different recommendation models. To take full advantage of content features, feature interactions such as cross features are used by some models and outperform than using raw features. However, in real-world systems, many content features are incomplete, e.g., we may know the occupation and gender of a user, but the values of other features (location, interests, etc.) are missing. This missing-feature-value (MFV) problem is harmful to the model performance, especially for models that rely heavily on rich feature interactions. Unfortunately, this problem has not been well studied previously.

Insulin pumps have been widely used by patients with diabetes. Insulin pump systems adopt wireless channel with few cryptographic mechanisms, which makes them vulnerable to many attacks. In this paper, we focus on the wireless channel between Carelink USB and insulin pump on which the attackers can launch message eavesdropping and/or therapy manipulation attacks, which may put the patient in a life-threatening situation. Some prior solutions such as certificate-based or token-based schemes need either complicated key management or additional devices. We propose a novel voiceprint-based access control scheme comprising anti-replay speaker verification and voiceprint-based key agreement to secure the channel between the Carelink USB and insulin pump. Our scheme does not need permanent key sharing or additional devices. The anti-replay speaker verification adopts cascaded fusion of speaker verification and anti-replay countermeasure to ensure the insulin pump can be accessed by Carelink USB only after the legitimate user passes the identity verification. The evaluation on ASVspoof 2017 datasets shows that our scheme achieves a 4.02% Equal Error Rate (EER) with the existence of replay impostors. Besides, our scheme uses energy-difference-based voiceprint extraction and secure multi-party computing to generate a common cryptography (temporary) key between the Carelink USB and insulin pump, which can be used to encrypt the subsequent communication, and protect the insulin pump from eavesdropping and therapy manipulation attacks. By appropriately setting the similarity threshold of voiceprints, our key agreement scheme allows the insulin pump to establish a secure channel only with the device in its close proximity.

The decoupled architecture and the fine-grained flow control feature of SDN limit the scalability of SDN network. In order to address this problem, some studies construct the flat control plane architecture, other studies build the hierarchical control plane architecture to improve the scalability of SDN. However, the two kinds of structure still have unresolved issues: the flat control plane structure can not solve the super-linear computational complexity growth of the control plane when SDN network scales to large size, the centralized abstracted hierarchical control plane structure brings path stretch problem. To address the two issues, we propose Orion, a hybrid hierarchical control plane for large-scale networks. Orion can effectively reduce the computational complexity growth of SDN control plane from super-linear to linear. Meanwhile, we design an abstracted hierarchical routing method to solve the path stretch problem. Further, Orion is implemented to verify the feasibility of the hybrid hierarchical approach. Finally, we verify the effectiveness of Orion both from the theoretical and experimental aspects.

Efficient transfer of bulk data requires routing that minimizes the net transfer time instead of providing flow level bandwidth guarantees. In this work, we consider a realistic scenario where available bandwidth for each link in a given network is time varying. In such a network and for a given file size, we provide an optimal algorithm that minimizes the total time required to transfer the file from source to destination. We further consider the problem where path shifting is allowed to increase the net throughput for bulk data transfer. For this problem, we provide a dynamic programming based optimal algorithm that minimizes the number of path shifts required to transfer the file in the specified time. Solution to the above problems addresses both the performance and scalability issues that arise in large bulk data transfer for long duration of time.

Faults in some sensor networks are likely to be localized. The conventional metric of fault-tolerance - connectivity of the network graph - fails to capture any notion of locality. This research introduces a new metric - region-based connectivity - that incorporates the notion of locality.

A large optical network may carry multiple traffic classes with different priorities and fault-tolerance requirement. Higher priority traffic may require having a back-up path so that the traffic can be switched quickly to this path in case of a failure in the primary path. The lower priority traffic classes may not have any such requirement. In the path protection schemes currently in use for the WDM networks, a backup path is computed for all traffic, whenever a primary path is established between a source-destination pair. The resource needed for communication using the backup path are reserved (or set aside) for data communication between a source-destination pair, and are utilized only when the primary path is unavailable due to a failure in the network. The traffic carrying capacity of a network can be increased, if the resources set aside for the backup paths are utilized for data communication. In this paper we propose a path protection scheme for networks with multiple classes of traffic. The key features of our scheme are (i) not all traffic classes have backup paths - only higher priority classes have backup paths, (ii) primary paths of lower priority share wavelengths with secondary paths of higher priority traffic, and (iii) lower priority traffic can be preempted by higher priority traffic in case of a failure. The sharing of a wavelength between a primary path of a lower priority communication with the secondary path of a higher priority communication allows the network to satisfy more call requests, thereby reducing the call blocking probability. We provide a mathematical programming formulation for computing the primary and backup paths for call requests in a dynamic environment. We also compute the call blocking probability of our scheme and compare it with the call blocking probability of the conventional scheme through simulation. Our experimental results show significant gain by the proposed scheme over the conventional scheme.

We consider the problem of routing the lightpaths of a logical topology of a WDM network on an arbitrary physical topology, such that the logical topology remains,connected even after the failure of a physical link. We focus our attention on the ring interconnection as the logical topology because it is widely used in many protection schemes. We first establish the necessary and sufficient condition for a ring logical topology to withstand failure of a single physical link. Next we show that the testing of this necessary and sufficient condition is an NP-complete problem. Finally, we give an algorithm for testing the necessary and sufficient condition and demonstrate the execution of the algorithm with the help of an example.

We consider the problem of routing the lightpaths of a logical topology of a WDM network on an arbitrary physical topology, such that the logical topology remains connected even after the failure of a physical link. In a previous paper Modiano et. al. (see Proc. IEEE INFOCOM'01, 2001) introduced the notion of survivable routing and established a necessary and sufficient condition for the existence survivable routes of a logical topology in a physical topology. In this paper we show that the problem of determining whether survivable routing is possible for a logical topology in a given physical topology is an NP-complete problem. Moreover we show that the problem remains NP-complete, even when the logical topology is restricted to be a ring with a specific ordering of the nodes.