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Pages
- Title
- A framework for distributed web services
- Creator
- Liu, Yew-Huey
- Date
- 1996
- Collection
- Electronic Theses & Dissertations
- Title
- A unified environment for distributed computing
- Creator
- Gendreau, Thomas Bernard
- Date
- 1987
- Collection
- Electronic Theses & Dissertations
- Title
- Adaptive key management for secure group communication
- Creator
- Bezawada, Bruhadeshwar
- Date
- 2005
- Collection
- Electronic Theses & Dissertations
- Title
- Autoconfiguration and security for wireless networks
- Creator
- Zhou, Hongbo
- Date
- 2005
- Collection
- Electronic Theses & Dissertations
- Title
- Capacity assurance in hostile networks
- Creator
- Li, Jian
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
-
Linear network coding provides a new communication diagram to significantly increase the network capacity by allowing the relay nodes to encode the incoming messages. However, this communication diagram is fragile to communication errors and pollution attacks. How to combat errors while maintaining the network efficiency is a challenging research problem. In this dissertation, we study how to combat the attacks in both fixed network coding and random network coding.For fixed network coding,...
Show moreLinear network coding provides a new communication diagram to significantly increase the network capacity by allowing the relay nodes to encode the incoming messages. However, this communication diagram is fragile to communication errors and pollution attacks. How to combat errors while maintaining the network efficiency is a challenging research problem. In this dissertation, we study how to combat the attacks in both fixed network coding and random network coding.For fixed network coding, we provide a novel methodology to characterize linear network coding through error control coding. We propose to map each linear network coding to an error control coding. Under this mapping, these two codes are essentially identical in algebraic aspects. Meanwhile, we propose a novel methodology to characterize a linear network coding through a series of cascaded linear error control codes, and to develop network coding schemes that can combat node compromising attacks. For random network coding, we propose a new error-detection and error-correction (EDEC) scheme to detect and remove malicious attacks. The proposed EDEC scheme can maintain throughput unchanged when moderate network pollution exists with only a slight increase in computational overhead. Then we propose an improved LEDEC scheme by integrating the low-density parity check (LDPC) decoding. Our theoretical analysis, performance evaluation and simulation results using ns-2 simulator demonstrate that the LEDEC scheme can guarantee a high throughput even for heavily polluted network environment.Distributed storage is a natural application of network coding. It plays a crucial role in the current cloud computing framework in that it can provide a design trade-off between security management and storage. Regenerating code based approach attracted unique attention because it can achieve the minimum storage regeneration (MSR) point and minimum bandwidth regeneration (MBR) point for distributed storage. Since then, Reed-Solomon code based regenerating codes (RS-MSR code and RS-MBR code) were developed. They can also maintain the MDS (maximum distance separable) property in code reconstruction. However, in the hostile network where the storage nodes can be compromised and the packets can be tampered with, the storage capacity of the network can be significantly affected.In this dissertation, we propose a Hermitian code based minimum storage regenerating (H-MSR) code and a Hermitian code based minimum bandwidth regenerating (H-MBR) code. We first prove that they can achieve the theoretical MSR bound and MBR bound respectively. We then propose data regeneration and reconstruction algorithms for the H-MSR code and the H-MBR code in both error-free networks and hostile networks. Theoretical evaluation shows that our proposed schemes can detect the erroneous decodings and correct more errors in the hostile network than the RS-MSR/RS-MBR code with the same code rate respectively.Inspired by the novel construction of Hermitian code based regenerating codes, a natural question is how to construct optimal regenerating codes based on the layered structure like Hermitian code in distributed storage. Compared to the Hermitian based code, these codes have simpler structures and are easier to understand and implement. We propose two optimal constructions of MSR codes through rate-matching in hostile networks: 2-layer rate-matched MSR code and m-layer rate-matched MSR code. For the 2-layer code, we can achieve the optimal storage efficiency for given system requirements. Our comprehensive analysis shows that our code can detect and correct malicious nodes with higher storage efficiency compared to the RS-MSR code. Then we propose the m-layer code by extending the 2-layer code and achieve the optimal error correction efficiency by matching the code rate of each layer's MSR code. We also demonstrate that the optimized parameter can achieve the maximum storage capacity under the same constraint. Compared to the RS-MSR code, our code can achieve much higher error correction efficiency. The optimized m-layer code also has better error correction capability than the H-MSR code.
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- Title
- Channel balancing strategies to optimize uplink utilization
- Creator
- Nalkund, Asok
- Date
- 2003
- Collection
- Electronic Theses & Dissertations
- Title
- Co-operative coded communication under network constraints
- Creator
- Misra, Kiran Mukesh
- Date
- 2010
- Collection
- Electronic Theses & Dissertations
- Title
- Communication performance of multicomputers
- Creator
- Chittor, Suresh Suryanarayana
- Date
- 1991
- Collection
- Electronic Theses & Dissertations
- Title
- Community detection in temporal multi-layer networks
- Creator
- Al-sharoa, Esraa Mustafa
- Date
- 2019
- Collection
- Electronic Theses & Dissertations
- Description
-
"Many real world systems and relational data can be modeled as networks or graphs. With the availability of large amounts of network data, it is important to be able to reduce the network's dimensionality and extract useful information from it. A key approach to network data reduction is community detection. The objective of community detection is to summarize the network by a set of modules, where the similarity within the modules is maximized while the similarity between different modules...
Show more"Many real world systems and relational data can be modeled as networks or graphs. With the availability of large amounts of network data, it is important to be able to reduce the network's dimensionality and extract useful information from it. A key approach to network data reduction is community detection. The objective of community detection is to summarize the network by a set of modules, where the similarity within the modules is maximized while the similarity between different modules is minimized. Early work in graph based community detection methods focused on static or single layer networks. This type of networks is usually considered as an oversimplification of many real world complex systems, such as social networks where there may be different types of relationships that evolve with time. Consequently, there is a need for a meaningful representation of such complex systems. Recently, multi-layer networks have been used to model complex systems where the objects may interact through different mechanisms. However, there is limited amount of work in community detection methods for dynamic and multi-layer networks. In this thesis, we focus on detecting and tracking the community structure in dynamic and multi-layer networks. Two particular applications of interest are considered including temporal social networks and dynamic functional connectivity networks (dFCNs) of the brain. In order to detect the community structure in dynamic single-layer and multi-layer networks, we have developed methods that capture the structure of these complex networks. In Chapter 2, a low-rank + sparse estimation based evolutionary spectral clustering approach is proposed to detect and track the community structure in temporal networks. The proposed method tries to decompose the network into low-rank and sparse parts and obtain smooth cluster assignments by minimizing the subspace distance between consecutive time points, simultaneously. Effectiveness of the proposed approach is evaluated on several synthetic and real social temporal networks and compared to the existing state-of-the-art algorithms. As the method developed in Chapter 2 is limited to dynamic single-layer networks and can only take limited amount of historic information into account, a tensor-based approach is developed in Chapter 3 to detect the community structure in dynamic single-layer and multi-layer networks. The proposed framework is used to track the change points as well as identify the community structure across time and multiple subjects of dFCNs constructed from resting state functional magnetic resonance imaging (rs-fMRI) data. The dFCNs are summarized into a set of FC states that are consistent over time and subjects. The detected community structures are evaluated using a consistency measure. In Chapter 4, an information-theoretic approach is introduced to aggregate the dynamic networks and identify the time points that are topologically similar to combine them into a tensor. The community structure of the reduced network is then detected using a tensor based approach similar to the one described in Chapter 3. In Chapter 5, a temporal block spectral clustering framework is introduced to detect and track the community structure of multi-layer temporal networks. A set of intra- and inter-adjacency matrices is constructed and combined to create a set of temporal supra-adjacency matrices. In particular, both the connections between nodes of the network within a time window, i.e. intra-layer adjacency, as well as the connections between nodes across different time windows, i.e. inter-layer adjacency are taken into account. The community structure is then detected by applying spectral clustering to these supra-adjacency matrices. The proposed approach is evaluated on dFCNs constructed from rs-fMRI across time and subjects revealing dynamic connectivity patterns between the resting state networks (RSNs)."--Pages ii-iii.
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- Title
- Comparative analysis of user experience with centralized vs. decentralized management of academic computing, administrative computing and telecommunication functions within an institution of higher education
- Creator
- Nogy, Jerry A.
- Date
- 1992
- Collection
- Electronic Theses & Dissertations
- Title
- Complex network problems in physics, computer science and biology
- Creator
- Cojocaru, Radu Ionut
- Date
- 2006
- Collection
- Electronic Theses & Dissertations
- Title
- Computer-mediated versus face-to-face communication in hierarchical team decision making
- Creator
- Hedlund, Jennifer
- Date
- 1993
- Collection
- Electronic Theses & Dissertations
- Title
- Cooperative resource sharing by integrating cellular and mobile Ad Hoc networks
- Creator
- Zhu, Danyu
- Date
- 2005
- Collection
- Electronic Theses & Dissertations
- Title
- Distributed parallel computing architecture for monitoring and control of large physical processes
- Creator
- Siebert, James Eugene
- Date
- 1977
- Collection
- Electronic Theses & Dissertations
- Title
- Dynamic process migration for load balancing in distributed systems
- Creator
- Xu, Chong-Wei
- Date
- 1986
- Collection
- Electronic Theses & Dissertations
- Title
- Economic gain-aware routing protocols for device-to-device content dissemination
- Creator
- Hajiaghajani Memar, Faezeh
- Date
- 2017
- Collection
- Electronic Theses & Dissertations
- Description
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"The objective of this dissertation is to investigate Device-to-Device content dissemination protocols for maximizing the economic gain of dissemination for given combinations of commercial and network parameters. " -- Abstract.
- Title
- Estimating available bandwidth for real-time supermedia applications
- Creator
- Chobanyan, Alexander
- Date
- 2007
- Collection
- Electronic Theses & Dissertations
- Title
- Flexible spectrum use in channel bonding wireless networks
- Creator
- Yang, Xi (Software engineer)
- Date
- 2014
- Collection
- Electronic Theses & Dissertations
- Description
-
Channel bonding, which assembles multiple narrow channels into one logical channel, can speed up data transmission and achieve better bandwidth utilization in wireless networks. Since introduced in 802.11n, channel bonding has been extended continually to support wider channels, making low-lag high-speed wireless communication possible. However, different radio technologies have different requirements on channel width. Devices that use different channel widths coexist in a contention domain...
Show moreChannel bonding, which assembles multiple narrow channels into one logical channel, can speed up data transmission and achieve better bandwidth utilization in wireless networks. Since introduced in 802.11n, channel bonding has been extended continually to support wider channels, making low-lag high-speed wireless communication possible. However, different radio technologies have different requirements on channel width. Devices that use different channel widths coexist in a contention domain may cause inefficiency and unfairness issues. For example, narrowband devices are easier to obtain medium access opportunities because they do not need to wait for the entire wide band to be idle. Therefore, although wideband devices can provide higher transmission speed, they are at an unfavorable position in contentions with narrowband devices.To this end, we propose a flexible spectrum use channel bonding (FSUB) protocol in which a node is allowed to start a transmission whenever there are some idle narrow channels and gradually increases the channel width during transmission. Because a node dynamically adjusts the channel width in a communication, we use a convolution method to achieve fast spectrum agreement between the transmitter and the receiver. To address contentions between devices in a wide band of spectrum, we introduce a compound preamble to make the collisions detectable in the frequency domain and use a parallel bitwise arbitration mechanism to quickly determine the winner. We implement and evaluate the proposed protocol through both the GNU Radio/USRP platform and ns-2 simulations. The results show that the proposed protocol well addresses the inefficiency and unfairness issues caused by heterogeneous radio coexistence. Channel bonding devices usingFSUB have more medium access opportunities and can aggregate wider channels than using other channel bonding protocols in presence of narrowband interference. The FSUB enables a device to always benefit from channel bonding without concerns about narrowband interference level.
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- Title
- Impacts of interactivity from computer-mediated communication in an organizational setting : a study of electronic mail
- Creator
- Ku, Linlin
- Date
- 1992
- Collection
- Electronic Theses & Dissertations
- Title
- Implementation of a high throughput low power MAC protocol in wireless sensor networks
- Creator
- Liu, Chin-Jung
- Date
- 2011
- Collection
- Electronic Theses & Dissertations
- Description
-
This thesis presents the design, implementation, and evaluation of TATD-MAC, a TDMA-based low duty cycle synchronous MAC protocol that improves throughput by increasing channel uti- lization with a traffic-adaptive time slot scheduling method. Conventional time division multiple access (TDMA) introduces significant end-to-end packet delivery delay and its throughput is lim- ited. TATD-MAC achieves higher throughput by improving TDMA with a novel traffic-adaptive mechanism that assigns time...
Show moreThis thesis presents the design, implementation, and evaluation of TATD-MAC, a TDMA-based low duty cycle synchronous MAC protocol that improves throughput by increasing channel uti- lization with a traffic-adaptive time slot scheduling method. Conventional time division multiple access (TDMA) introduces significant end-to-end packet delivery delay and its throughput is lim- ited. TATD-MAC achieves higher throughput by improving TDMA with a novel traffic-adaptive mechanism that assigns time slots only to nodes that are expecting traffic. Our traffic-adaptive mechanism is a two-phase design, which decomposes the DATA period into traffic notification part and data transmission scheduling part. The two-phase design enables TATD-MAC to optimize the control packets and improve their energy efficiencies according to the characteristics of each phase. The source nodes inform all nodes on the routing path that these sources have outgoing traffic by transmitting traffic notification packets in a "pulse" fashion. With traffic notification packets, ev- ery node on the routing path claims time slots in data transmission part. Therefore, TATD-MAC is able to forward a packet over multiple hops in a single cycle and thus reduce the end-to-end delay. The data transmission scheduling mechanism only assigns time slots to nodes with traf- fic through an ordered schedule negotiation scheme. This innovative traffic-adaptive scheduling mechanism assigns time slots based on traffic and totally eliminates the idle listening slots on nodes with no traffic. Moreover, if any other nodes need more time slots, they are able to claim them, which further improves channel utilization and achievable throughput. We implemented a TATD-MAC prototype on Tmote-Sky running TinyOS 2.1.0. Performance evaluation shows that TATD-MAC significantly improves throughput compared to conventional TDMA and achieves the same throughput as TDMA with slot stealing while having 70% less power consumption.
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