Cryptography is the art of protecting information by encrypting the original message into an unreadable format. A cryptographic hash function is a hash function which takes an arbitrary length of the text message as input and converts that text into a fixed length of encrypted characters which is infeasible to invert. The values returned by the hash function are called as the message digest or simply hash values. Because of its versatility, hash functions are used in many applications such as message authentication, digital signatures, and password hashing [Thomsen and Knudsen, 2005]. The purpose of this study is to apply Huffman data compression algorithm to the SHA-1 hash function in cryptography. Huffman data compression algorithm is an optimal compression or prefix algorithm where the frequencies of the letters are used to compress the data [Huffman, 1952]. An integrated approach is applied to achieve new compressed hash function by integrating Huffman compressed codes in the core functionality of hashing computation of the original hash function.

Campus networks have recently experienced a proliferation of devices ranging from personal use devices (e.g. smartphones, laptops, tablets), to special-purpose network equipment (e.g. firewalls, network address translation boxes, network caches, load balancers, virtual private network servers, and authentication servers), as well as special-purpose systems (badge readers, IP phones, cameras, location trackers, etc.). To establish directives and regulations regarding the ways in which these heterogeneous systems are allowed to interact with each other and the network infrastructure, organizations typically appoint policy writing committees (PWCs) to create acceptable use policy (AUP) documents describing the rules and behavioral guidelines that all campus network interactions must abide by. While users are the audience for AUP documents produced by an organization's PWC, network administrators are the responsible party enforcing the contents of such policies using low-level CLI instructions and configuration files that are typically difficult to understand and are almost impossible to show that they do, in fact, enforce the AUPs. In other words, mapping the contents of imprecise unstructured sentences into technical configurations is a challenging task that relies on the interpretation and expertise of the network operator carrying out the policy enforcement. Moreover, there are multiple places where policy enforcement can take place. For example, policies governing servers (e.g., web, mail, and file servers) are often encoded into the server's configuration files. However, from a security perspective, conflating policy enforcement with server configuration is a dangerous practice because minor server misconfigurations could open up avenues for security exploits. On the other hand, policies that are enforced in the network tend to rarely change over time and are often based on one-size-fits-all policies that can severely limit the fast-paced dynamics of emerging research workflows found in campus networks. This dissertation addresses the above problems by leveraging recent advances in Software-Defined Networking (SDN) to support systems that enable novel in-network approaches developed to support an organization's network security policies. Namely, we introduce PoLanCO, a human-readable yet technically-precise policy language that serves as a middle-ground between the imprecise statements found in AUPs and the technical low-level mechanisms used to implement them. Real-world examples show that PoLanCO is capable of implementing a wide range of policies found in campus networks. In addition, we also present the concept of Network Security Caps, an enforcement layer that separates server/device functionality from policy enforcement. A Network Security Cap intercepts packets coming from, and going to, servers and ensures policy compliance before allowing network devices to process packets using the traditional forwarding mechanisms. Lastly, we propose the on-demand security exceptions model to cope with the dynamics of emerging research workflows that are not suited for a one-size-fits-all security approach. In the proposed model, network users and providers establish trust relationships that can be used to temporarily bypass the policy compliance checks applied to general-purpose traffic -- typically by network appliances that perform Deep Packet Inspection, thereby creating network bottlenecks. We describe the components of a prototype exception system as well as experiments showing that through short-lived exceptions researchers can realize significant improvements for their special-purpose traffic.

Most systems in HPC make use of hierarchical designs that allow multiple levels of parallelism to be exploited by programmers. The use of multiple multi-core/multi-processor computers to form a computer cluster supports both fine-grain and large-grain parallel computation. Aggregate function communications provide an easy to use and efficient set of mechanisms for communicating and coordinating between processing elements, but the model originally targeted only fine grain parallel hardware. This work shows that a hierarchical implementation of aggregate functions is a viable alternative to MPI (the standard Message Passing Interface library) for programming clusters that provide both fine grain and large grain execution. Performance of a prototype implementation is evaluated and compared to that of MPI.

To get the best prices, sweet cherry growers must supply blemish-free fruit. Unfortunately, mature cherries have a fragile composition, rendering them susceptible to damage from heat, wind, birds, and rain. Rain is particularly devastating, because cherries split when they absorb too much water. Since rainstorms are common in the otherwise arid regions where most cherries are grown, growers must have a system for quickly deploying rain removal methods. The current industry solution relies on human observation and implementation, which is error-prone and costly. This project proposes an automated cherry wetness system using a Decagon Devices leaf wetness sensor (LWS) and a wireless sensor network (WSN). The research consists of analyzing industry and literature for uses of WSNs and LWSs in orchards and testing a LWS in a prototype WSN. The system will be evaluated for its potential to provide a precision-agriculture solution to the problem of remote cherry wetness detection.

In recent years, mobile devices have played a significant role in daily life. As a result, Mobile Applications have become very popular. An increasing number of people are using mobile applications to handle an increasing number of personal tasks, as well as for amusement. To date, there are thousands of mobile applications available for a variety of purposes. However, there are very few specifically designed for local church use. Mobile applications are potentially more convenient and easier to operate than normal website for parishioners. Designing and implementing a mobile application for Crest Community Church, in Riverside, based on Android Developer Tools (ADT) and Android Software Development Kit (Android SDK) is this project’s primary objective. The objective of this project is to provide a communications platform where members of Crest Community Church can share news, discuss coming church events, promote and enhance the connectivity of this worship community, and provide mobile access to information not available on their present systems. A distinct feature of this project allows for communication between mobile application and webserver by creating a HTTP URL Connection. As a result, church members can publish news and events in a discussion forum as well as a dialog with other church members in a near real time format. The Crest users can also indicate that posted prayer request has been prayed for. In addition, this new application displays general church information, and provides the address and driving direction for potential visitors. Church members can also check the church’s calendar of events, special meetings and information about the Passion Center for Children ministry. This project has the ability to store and track pertinent information about each user, the content of all discussions, and retains member’s key contact data. This project successfully implemented a church mobile application. It demonstrated that a tailored mobile application can enhance the sense of community via internet for this congregation. It feather shows that mobile applications can greatly assist churches in community with members as well as visitors. The application also expanded the internet footprint of Crest Community Church, and offers other churches an avenue to improve their connectivity for the future.

The main aim of the project is to launch multiple processes and have those processes communicate with each other using peer to peer communication to eliminate the problems of multiple processes running on a single server, and multiple processes running on inhomogeneous servers as well as the problems of scalability. This entire process is done using MPICH which is a high performance and portable implementation of Message Passing Interface standard. The project involves setting up the passwordless authentication between two local servers with the help of SSH connection. By establishing a peer to peer communication and by using a unique shell script which is written using MPICH and its derivatives, I am going to demonstrate the process of inter-process communication between the servers.

Aim: To evaluate the ability of a publicly available facial recognition application program interface (API) to calculate similarity scores for pre- and post-surgical photographs of patients undergoing orthognathic surgeries. Our primary objective was to identify which surgical procedure(s) had the greatest effect(s) on similarity score. Methods: Standard treatment progress photographs for 25 retrospectively identified, orthodontic-orthognathic patients were analyzed using the API to calculate similarity scores between the pre- and post-surgical photographs. Photographs from two pre-surgical timepoints were compared as controls. Both relaxed and smiling photographs were included in the study to assess for the added impact of facial pose on similarity score. Surgical procedure(s) performed on each patient, gender, age at time of surgery, and ethnicity were recorded for statistical analysis. Nonparametric Kruskal-Wallis Rank Sum Tests were performed to univariately analyze the relationship between each categorical patient characteristic and each recognition score. Multiple comparison Wilcoxon Rank Sum Tests were performed on the subsequent statistically significant characteristics. P-Values were adjusted for using the Bonferroni correction technique. Results: Patients that had surgery on both jaws had a lower median similarity score, when comparing relaxed expressions before and after surgery, compared to those that had surgery only on the mandible (p = 0.014). It was also found that patients receiving LeFort and bilateral sagittal split osteotomies (BSSO) surgeries had a lower median similarity score compared to those that received only BSSO (p = 0.009). For the score comparing relaxed expressions before surgery versus smiling expressions after surgery, patients receiving two-jaw surgeries had lower scores than those that had surgery on only the mandible (p = 0.028). Patients that received LeFort and BSSO surgeries were also found to have lower similarity scores compared to patients that received only BSSO when comparing pre-surgical relaxed photographs to post-surgical smiling photographs (p = 0.036). Conclusions: Two-jaw surgeries were associated with a statistically significant decrease in similarity score when compared to one-jaw procedures. Pose was also found to be a factor influencing similarity scores, especially when comparing pre-surgical relaxed photographs to post-surgical smiling photographs.

Quadrature amplitude modulation (QAM) is a highly bandwidth efficient transmission technique for digital communications. It makes use of multiple signal phase and amplitude levels to carry multiple bits per symbol. This requires accurate and robust carrier phase and frequency estimation in the receiver. / Thesis (PhDElectronicEngineering)--University of South Australia, 2002

This thesis examines the sampling and jitter specifications and considerations for Global Navigation Satellite Systems (GNSS) software receivers. Software Radio (SWR) technologies are being used in the implementation of communication receivers in general and GNSS receivers in particular. With the advent of new GPS signals, and a range of new Galileo and GLONASS signals soon becoming available, GNSS is an application where SWR and software-defined radio (SDR) are likely to have an impact. The sampling process is critical for SWR receivers where it occurs as close to the antenna as possible. One way to achieve this is by BandPass Sampling (BPS), which is an undersampling technique that exploits aliasing to perform downconversion. In this thesis, the allowable sampling frequencies are calculated and analyzed for the multiple frequency BPS software radio GNSS receivers. The SNR degradation due to jitter is calculated and the required jitter standard deviation allowable for wach GNSS band of interest is evaluated and a basic jitter budget is calculated that could assist in the design of multiple frequency SWR GNSS receivers. Analysis shows that psec-level jitter specifications are required in order to keep jitter noise well below the thermal noise for software radio satellite navigation receivers. However, analysis of a BPSK system shows that large errors occur if the jittered sample crosses a data bit boundary. However, the signal processing techniques required to process the BOC modulation are much more challenging than those for traditional BPSK. BOC and AltBOC have more transitions per chip of spreading code and hence jitter creates greater SNR degradation. This work derives expressions for noise due to jitter taking into account the transition probability in QPSK, BOC, AltBOC systems. Both simulations and analysis are used to give a better understanding of jitter effects on Software Radio GNSS receivers.

Wireless ATM plays a key role in the realization of broadband wireless networks. The transmission of various classes of traffic and the provision of bandwidth on demand over a wireless channel poses a number of new technical challenges. This thesis addresses the design of a low cost adaptive transmitter for fixed wireless ATM/B-ISDN systems with emphasis on optimum use of wireless network resources. A new architecture for a direct microwave wireless ATM transmitter is proposed. The transmitter capacity adaptation is implemented by using an admission control metric and an M-QAM modulator. The two main components of the transmitter are: an M-QAM control unit and a direct microwave QAM modulator unit. The M-QAM control unit is used to select an optimum modulation level for the QAM modulator. The modulation level is adjusted based on the bandwidth demand, QoS requirements, and outage conditions of the wireless ATM link. The direct microwave QAM modulator unit transforms the broadband traffic to a modulated microwave signal that is suitable for transmission over a wireless network. The required bandwidth of the broadband traffic is estimated using an effective bandwidth metric. An analytical relation, called the capacity reduction factor, is derived to represent the performance degradation due to the wireless channel and channel fading in a B-ISDN network. Using the effective bandwidth metric and the capacity reduction factor, a QoS metric for the wireless broadband network is introduced. This metric is termed as, modified effective bandwidth. This metric is used to adapt the M-QAM modulator. Another significant contribution of this research work is a new architecture for the direct QAM modulator. This is based on use of PIN diode reflection attenuators. The PIN diodes operate in forward bias condition thereby overcoming the speed limitation problem due to charge storage. Using residue theory, analytical results to model the large signal forward bias operation of PIN diodes are presented. This theory also examines the transition time of a PIN diode with bias changes from a reverse bias to a forward bias. The direct microwave QAM modulator implementation using MIC and silicon MMIC technologies is examined. While a realization using MIC is simple and straightforward, a silicon MMIC realization offers a very cost effective solution. A system study was conducted to examine the operation of the adaptive direct microwave M-QAM modulator in the wireless channel with ATM traffic. The operation has been examined for different wireless channels and for various classes of traffic. The call acceptance and outage performance are compared with those for a fixed QAM modulator. The results show that the proposed system can be used for implementation of cost effective adaptive transmitters for broadband wireless applications.