Approved for public release, distribution is unlimited / In this thesis, the scalability issues of Simple Network Management Protocol (SNMP) in optical network management are explored. It is important to understand the effect of varying the number of nodes, the request inter-arrival times and the polling interval on the performance of SNMP and number of nodes that can be effectively managed. The current study explored the effect of varying these parameters in a controlled test environment using the OPNET simulation package. In addition, traffic analysis was performed on measured SNMP traffic and statistics were developed from the traffic analysis. With this understanding of SNMP traffic, an SNMPv1 model was defined and integrated into an OPNET network model to study the performance of SNMP. The simulation results obtained were useful in providing needed insight into the allowable number of nodes an optical network management system can effectively manage. / Civilian, Singapore Ministry of Defense

Approved for public release, distribution is unlimited / This thesis studies and discusses the development of the API, called the persistency API, for supporting the persistent data sessions. Without persistent session support, network applications often need to be restarted from the beginning when intermittent physical connection loss happens. Application programmers can use the persistency API to achieve the service continuity. The persistency API provides the interface that allows a program to continue retrieve data from the point the connection is lost after the physical connection is restored. The focus of this thesis is to develop a generalized persistency API that supports various types of applications. This thesis studies the persistent session support for two types of transport protocols, TCP and UDP, which are used by major network applications. An application that performs text file and video file transfer is implemented to demonstrate the persistent data transfer sessions for TCP and UDP, respectively. The study shows that the proposed APIs can support the data transfer continuity in the reconnection process. / Captain, Royal Thai Army

No description available.

M.Ing. (Electrical and Electronic Engineering) / With all the talk about the Information Highway and its construction, there is also a channel which is highly underestimated and thus almost ignored. On normal FM radio transmissions extra bandwidth exists, suitable for the transmission of audio and data. In this thesis the effects of interference on data transmission over the Supplementary Signal Transmission (SST) channel are analysed. The channel is characterized in terms of the Bit Error Rate (BER) versus field strength and distance from a transmitter ...

As quantum computers continue to develop, they pose a threat to cryptography since many popular cryptosystems will be rendered vulnerable. This is because the security of most currently used asymmetric systems requires the computational hardness of the integer factorization problem, the discrete logarithm or the elliptic curve discrete logarithm problem. However, there are still some cryptosystems that resist quantum computing. We will look at code-based cryptography in general and the McEliece cryptosystem specifically. Our goal is to understand the structure behind the McEliece scheme, including the encryption and decryption processes, and what some advantages and disadvantages are that the system has to offer. In addition, using the results from Courtois, Finiasz, and Sendrier's paper in 2001, we will discuss a digital signature scheme based on the McEliece cryptosystem. We analyze one classical algebraic attack against the security analysis of the system based on the distinguishing problem whether the public key of the McEliece scheme is generated from a generating matrix of a binary Goppa code or a random binary matrix. The idea of the attack involves solving an algebraic system of equations and we examine the dimension of the solution space of the linearized system of equations. With the assistance from a paper in 2010 by Faugere, Gauthier-Umana, Otmani, Perret, Tillich, we will see the parameters needed for the intractability of the distinguishing problem. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2015. / FAU Electronic Theses and Dissertations Collection

Data originating from non-voice sources is expected to play an increasingly important role in the next generation mobile communication services. To plan these networks, a detailed understanding of their traffic load is essential. Recent experimental studies have shown that network traffic originating from data applications can be self-similar, leading to a different queueing behavior than predicted by conventional traffic models. Heavy tailed probability distributions are appropriate for capturing this property, but including those random processes in a performance analysis makes it difficult and often impossible to find numerical results. In this thesis three related topics are addressed: It is shown that Markovian models with a large state space can be used to describe traffic which is self-similar over a large time scale, a Maximum Likelihood approach to fit parallel Erlang-k distributions directly to time series is developed, and the performance of a channel assignment procedure in a wireless communication network is evaluated using the above mentioned techniques to set up a Markovian model. Outcomes of the performance analysis are blocking probabilities and latency due to restrictions of the channel assignment procedure as well as estimations of the overall bandwidth that the system is required to offer in order to support a given number of users.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Includes bibliographical references. / by Susan Aileen Hall. / M.S.

The Kentucky Mesonet is a high-density, mesoscale network of automated meteorological and climatological sensing platforms being developed across the commonwealth. Data communications, collection, processing, and delivery mechanisms play a critical role in such networks, and the World Meteorological Organization recognizes that “an observing system is not complete unless it is connected to other systems that deliver the data to the users.” This document reviews the implementation steps, decisions, and rationale surrounding communications and computing infrastructure development to support the Mesonet. A general overview of the network and technology-related research is provided followed by a review of pertinent literature related to in situ sensing network technology. Initial infrastructure design considerations are then examined followed by an in-depth review of the Mesonet communications and computing architecture. Finally, some general benefits of the Mesonet to the citizens of Kentucky are highlighted.

The objective of this dissertation is to investigate the performance of the recently proposed MIMO technology in real indoor environments based on channel measurements centered at 5.8 GHz. First, a MIMO channel measurement system is implemented based on the virtual antenna array infrastructure. This measurement testbed can acquire the wideband channel matrices of MIMO systems with arbitrary array geometries. The measurement system structure and measurement procedure are described in detail in the first part. The second part is about MIMO channel modeling. Two novel number-of-sources detection algorithms, which are more robust and suitable for practical applications than traditional methods, are proposed. The MIMO path parameters, including delay, DOA, and DOD are estimated from measured data by several estimation schemes based on the ESPRIT algorithm. The accuracies of these estimation schemes are evaluated in terms of the estimation error between the capacities of the directly measured and the reconstructed channels. Moreover, based on ray tracing and measurement results, the spherical wave model is suggested to replace conventional plane wave model in order to prevent the capacity underestimation of short-range MIMO channels. An important observation is that short-range MIMO can achieve full capacity in free space channel. A threshold distance is derived to determine whether the spherical wave model is necessary. In the final part, measurements conducted in the Residential Laboratory are used to investigate the impact of element spacing, LOS, interference, spatial correlation between the interfering and data links, and stream control. A capacity enhancement scheme, which improves the performance by adapting the element locations, is implemented using our measurement system. Finally, the performances of beam selection and antenna selection in combination with MIMO technologies are compared in both narrowband and wideband channels.

Parents and children increasingly spend time living apart due to marital separation and work travel. I investigated parent--child separation in both of these contexts to find that current technologies frequently do not meet the needs of families. The telephone is easy-to-use and ubiquitous but does not provide an engaging way of communicating with children. Videochat is more emotionally expressive and has a greater potential for engagement but is difficult to set up and cannot be used by a child without the help of an adult. Both telephone and videochat fail to meet the needs of remote parenting because they focus on conversation rather than care and play activities, which are the mechanism by which parents and children build closeness. I also saw that in both types of separation the motivation to connect at times conflicted with desire to reduce disruption of the remote household. To address some of these issues, I designed a system called the ShareTable, which provides easy-to-initiate videochat with a shared tabletop activity space. After an initial lab-based evaluation confirmed the promise of this approach, I deployed the ShareTable to four households (two sets of divorced families). I collected data about the families' remote interactions before and during the deployment. Remote communication more than doubled for each of these families while using the ShareTable and I saw a marked increase in the number of communication sessions initiated by the child. The ShareTable provided benefits over previous communication systems and supported activities that are impossible with other currently available technologies. One of the biggest successes of the system was in providing an overlapped video space that families appropriated to communicate metaphorical touch and a sense of closeness. However, the ShareTable also introduced a new source of conflict for parents and challenged the families as they tried to develop practices of using the system that would be acceptable to all involved. The families' approach to these challenges as well as explicit feedback about the system informs future directions for synchronous communication systems for separated families.