In this research, the concept of piggybacking has been extended to concatenate Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) packets. In any given network scenario, voice (UDP) is given priority over data (TCP) packet. During high traffic load, a UDP packet is processed at a higher priority, thus accumulating the TCP packets and leading to congestion and retransmission of TCP packets. Because it is challenging to integrate UDP and TCP packets an efficient queuing model has been proposed to concatenate the packets without causing a negative impact on UDP or voice traffic. In this paper, we propose the algorithm and model to concatenate UDP and TCP packets into a single packet and obtain better throughput for TCP traffic, efficient utilization of network bandwidth. The concatenation is performed based on parameters such as priority, destination and MTU size. The concept of discrete-time Markov chain has been leveraged to analyze the router utilization and efficiently handle the concatenated packets. The PCATTCP tool has been used to study the performances of UDP and TCP packets traversing a LAN between two end hosts. These values have been used for the simulation of the problem. Discrete Event Simulation has also been performed to determine the optimal values and associated system parameters. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The growth of wireless technology has developed since the invention of wireless devices. With the recent introduction of smart phones and other latest mobile devices, the growing need for networking is limitless. This calls for a more efficient Adhoc network formed on the go. The goal is to improve the MANET type of Adhoc networks. This infrastructure less network has routing protocols to route the packets to the intended recipient in an organized manner. AODV protocol chooses the best path to the destination based on the hop count as metric it has no power, stability and bandwidth optimization. Considering the current need, the resource needs to be utilized in an efficient manner so that the requests are met in a timely manner. This research proposes a stable, energy aware ,bandwidth, optimized metric to load balance the traffic between available non-overlapping channels in 802.11[1] standards. The proposed protocol has proved to have 50% better performance. It has avoided additional overhead for the control packet and accounted for another important broadcast storm problem by avoiding HELLO (Used as keep alive) packets used to discover neighboring nodes. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering & Computer Science.

A multi-core system provides improved performance/power ratio than a single-core one. However, multi-core architecture suffers from thermal constraint and data inconsistency. Current multi-core system is not adequate to increase memory-level parallelism and cache performance due to its poor core-to-core interconnection topology. In some architecture, like MIT Raw, each node/core has computing and switching components. Switching component of such a node consumes power while the node is only computing and vice versa. In this paper, we propose a design methodology to reduce the number of switches in multi-core architecture without compromising the performance. According to this method, nodes are separated between computing cores and network switches. Using folded torus topology, we develop a scheme to connect the components (cores and switches) in the multi-core architecture. We use multi-core architectures with various numbers of nodes (cores and switches) to evaluate the proposed methodology. Using synthetic workload, we obtain the core-to-core communication delay and total power consumption for MIT RAW, Triplet Based Architecture (TriBA), Logic-Based Distributed Routing (LBDR), and the proposed architecture. Experimental results show that the proposed architecture outperforms Raw, TriBA, and LBDR by cutting down the need for the number of switches significantly. According to the results, proposed architecture reduces total power consumption approximately by 77% and average delay by 54%. Power reduction comes from the fact that number of switches is cut down. Average delay is decreased as each switch provides adequate communicate channels. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Lespedeza cuneata is an Asian legume introduced to the U.S. in the 1930s as erosion control and forage, but it can also have strong negative effects on native species and in some cases form dense monocultures. One proposed explanation for this invasive success is that L. cuneata produces allelopathic chemicals that either directly suppresses native species or indirectly alters soil chemistry or microbial communities in ways that give L. cuneata a competitive advantage. Additionally, L. cuneata may have competitive advantages over native species that operate independently or in conjunction with these allelopathic mechanisms. To test these hypotheses, I collected soil from a previous three-year field experiment in which L. cuneata was established in or excluded from randomly selected plots in a common soil type and site history. A series of greenhouse experiments were designed to isolate putative allelopathic effects, resource competition and effects of neighbor identity on native plants. Invaded soil had positive effects on L. cuneata biomass while native biomass decreased for several native species. Additionally, water manipulation resulted in significant interactions with soil history or neighbor identity for a subset of the native species, indicating that resource competition may impact invasive success of sericea. These results support the hypothesis that L. cuneata can create a positive feedback that may increase invasion potential, as well as directly impacting growth of natives,and these effects may be intensified by low water conditions. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Biology.

For this exploratory study, flight data of a Bell Model 205A-1 helicopter, flying under contract to the United States Forest Service, is analyzed to investigate its operational conditions. Usage of the helicopter, specifically the missions performed, and phases occurring within those missions, is determined; as well as finding the magnitude and classification of vertical loads that occurred in the course of operation. As a result, it is determined that the helicopter was required to carry out seven distinguishable types of missions; and within those missions, the helicopter performed ten flight phase types, three of which were mission specific. A program code is written to determine these phases and mission types. Data is presented to show the flight usage of the helicopter for all mission types, as well as the specific phases occurring within those missions. Due to placement of the accelerometers in the nose of the aircraft, separation of gust and maneuver loads is difficult. A method is presented to classify vertical loads into three categories based upon roll and pitch rates of the helicopter. Flight load data is presented to help understand the loading the helicopter experiences through its overall flights along with the maximum and minimum loads experienced in individual flight phases. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.

The study of energy-absorbing behavior in sandwich beams under static loading has become the basis for the design of crashworthy structure in automobile applications. Unlike metals, composite sandwich materials display little or no plastic deformation. Research has shown that foam-cored sandwich beam has significantly higher energy absorption than low carbon/high carbon steel used in automobiles.This thesis is aimed at developing a structural component that provides better kinetic energy absorption, than the existing car front bumper. Occupants of motor vehicles are injured or killed in several different types of crash situations. These are frontal, side, rear, and rollover. The most severe accident situations are frontal impact. The car front bumper is a major structural component, and it carries most of the impact load in crash events. Therefore, in order to improve the front bumper performance, an attempt is made in this study to use sandwich material in the front bumper. And for that, a study is carried out to arrive at a combination of core and face sheet that offers maximum energy absorption. A Finite Element (FE) model of a Ford Taurus is first utilized and validated, using the LS-Dyna FE software. Frontal crash analysis is then performed on the car with sandwich bumper model according to the Federal Motor Vehicle Safety Standard 208 (FMVSS 208) and the New Car Assessment Program (NCAP). The vehicle displacements, energy absorption, and deceleration levels are compared for both the steel and sandwich models. Occupant injuries are then evaluated for frontal impact sled test at 35 mph, using the LS-Dyna, for both steeel and the new composite models. The injury levels including, head, neck and chest injuries are evaluated and compared for the both models. It is demonstrated that foam-cored sandwich beam with carbon/epoxy face sheet is more effective than the present steel car bumper. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

In this thesis, the bit error rate (BER) performance of a relay network using both a partial compute-and-forward (PCF) strategy and a decode-and-forward (DF) strategy is studied. The system model considered is a relay network, which has multiple sources, multiple relay nodes, and one destination. First, in this thesis, BER performance of the relay network is analyzed using a decode-and-forward strategy. Second, another approach, called a partial compute-and-forward strategy, is proposed. The key idea here is to add dither, to the transmitted messages, then encode and forward the messages to the relay nodes like lattice codes. Once the relay nodes receive the linear combination of transmitted signals, they first remove the dithered signal and then map it to a linear combination of the transmitted message. This linear combination of the message is forwarded to the destination under a power constraint at the relay. Results show that the BER performance of the partial compute-and-forward strategy is better than the decode-and-forward strategy applied at the relay nodes. This thesis also analyzes the BER performance of a four-user physical-layer network coding (PNC), the implementation of which enhances the throughput and routing capabilities of a relay network. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The Tian Shan region was identified as the source of Permian fluvial-lacustrine fills in the greater Turpan-Junggar basin. Thin-section petrographic study of thirty-six fine to very coarse lithic arenites from Upper Permian-Basal Triassic Wutonggou low-order cycle suggests both distant Tian Shan and local intrabasinal rift shoulders were sources. Two petrofacies are identified on the basis of QFL composition. Petrofacies A (mean Q2F4L94, Qm2F4Lt94, Qm42P57K1, and Qp0Lv49Ls51) occurs in the lower Wutonggou low-order cycle, which is characterized by repetitive shifts between fluvial and deltaic depositional cycles. Petrofacies B (mean Q26F9L65, Qm17F9Lt74, Qm65P25K10, and Qp13Lv55Ls32) occurs in the upper Wutonggou low-order cycle, which is dominated by deltaic depositional cycles. Abundant mudrock and basaltic lithics in Petrofacies A suggest intrabasinal rift shoulders were the primary source for the lower Wutonggou low-order cycle. During the deposition of lower Wutonggou, the greater Turpan-Junggar Basin was probably composed of highly partitioned grabens and half-grabens, similar to the Quaternary Basin and Range Province of the western U.S. The abrupt increase in quartz and decrease in basaltic lithics, coupled with changes in paleocurrents and depositional style in the upper Wutonggou low-order cycle, suggest a different catchment with a larger drainage fed the Wutonggou lake. The grabens and half-grabens during the deposition of upper Wutonggou were more interconnected, receiving sediments derived from both distant Tian Shan and local rift shoulders. The documented data best support a rift model, but the underlying cause of rifting remains to be examined. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Geology.

The cure kinetics of an epoxy resin with surface modified silica filler (Nanopox F 400 resin) and without silica filler (DGEBA resin), cured with an amine curing agent, DDS at an N-H/epoxy molar ratio of 1.1:1 was studied by Dynamic Scanning Calorimetry in two basic modes; Dynamic temperature scanning and Isothermal temperature scanning. Dynamic temperature scanning analysis suggests that the addition of surface modified silica nanoparticles in the epoxy resin increases the rate of reaction by acting as a catalyst. The hydroxyl groups in silica nanoparticles catalyze the cure reaction by shifting the exothermic peak towards the lower temperature. Under dynamic temperature scanning, the glass transition temperature (Tg) was lower for the Nanopox F 400 system than the unfilled control system. The glass transition temperature and changes in the Tg found in DSC analysis were in line with TMA analysis and DMA analysis. Isothermal scanning analysis shows that the control system follows the Kamal autocatalytic model whereas Nanopox F 400 system follows the modified Kamal autocatalytic model. The model parameters were determined by a nonlinear multiple regression method. The mechanical properties of Nanopox F 400 resin and control resin both cured with DDS at an N-H/epoxy molar ratio of 1.1:1 were examined by tensile testing. The tensile results showed increase in modulus and decrease in tensile strength for 40 wt. % surface modified Nanopox F 400 system compared to the control system. The effect of processing technique and silica content on the tensile properties of silica reinforced epoxy resin was further analyzed. The structure of Nanopox F 400 resin was characterized by FT-IR spectroscopy and 1H NMR spectroscopy. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry.

A production system converts raw materials into finished goods by various processes. The processes could occur parallel in order to reduce the time taken to complete the processes. Critical path in production systems is the maximum time taken to complete processes occurring in parallel. Identifying critical paths are important because, in order to improve the cycle time emphasis needs to be given to the critical path. Critical path is usually a single path in deterministic processing times. Due to variability more than one path might tend to be critical within the same system. The initial part of this research focuses on identifying changes in critical paths in variable processing times and prioritization of paths. Several metrics such as critical path severity index, all path severity indexes, probability of critical path beyond standard time are used to identify the criticality of paths. Next, suitable tools are implemented within these paths in order to improve the probability of completion and reduce the costs due to delay. An economic analysis for using lean tools within the paths is done. The allocation of improvement tools is based on the variability of each process and the processing time / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering.