International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Packet Telemetry Ground Station which receives telemetry data from the Space Station must be able to receive and process various data types including high-rate video, audio, instrumentation, electronic mail, telecommand, and engineering. The Packet Telemetry Ground Station must also be flexible to accommodate changing missions and payloads. Computer simulations of the Packet Telemetry Ground Station provide information about device specifications required to achieve an acceptable level of performance under changing telemetry data traffic configurations. This paper describes a computer simulation model for a Packet Telemetry Ground Station Architecture which was tested using ten different traffic components randomly transmitting data. The Packet Telemetry Ground Station Simulation status and utilization plots are discussed in terms of interpreting the simulation results.

No description available.

Hung, Kwok-Wah. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1991. / Bibliography: leaves 109-111. / ACKNOWLEDGEMENTS / ABSTRACT / Chapter CHAPTER 1 --- Overview of Packet Radio Networks --- p.1 / Chapter 1.1 --- Introduction --- p.2 / Chapter 1.2 --- Network Structure --- p.3 / Chapter 1.3 --- Channel Access Protocol --- p.3 / Chapter 1.4 --- Spatial Reuse --- p.5 / Chapter 1.5 --- Spread Spectrum --- p.6 / Chapter 1.6 --- Thesis Introduction --- p.8 / Chapter CHAPTER 2 --- Design Algorithms for Networks with Directional Antennas --- p.12 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- Problems in The MTCD/MDA Protocol --- p.14 / Chapter 2.3 --- The Simple Tone Sense (STS) Protocol --- p.15 / Chapter 2.4 --- The Variable Power Tone Sense (YPTS) Protocol --- p.18 / Chapter 2.5 --- Network Design Algorithms --- p.19 / Chapter 2.6 --- Network Design Example --- p.25 / Chapter 2.7 --- Simulation Results --- p.28 / Chapter 2.8 --- Chapter Summary --- p.31 / Chapter CHAPTER 3 --- The Coded Tone Sense Protocol --- p.44 / Chapter 3.1 --- Introduction … --- p.45 / Chapter 3.2 --- System Model and Code Assignment Algorithm --- p.46 / Chapter 3.3 --- Protocol Description --- p.48 / Chapter 3.4 --- Simulation Results --- p.49 / Chapter 3.5 --- Chapter Summary --- p.51 / Chapter CHAPTER 4 --- An Efficient Spreading Code Assignment Algorithm --- p.54 / Chapter 4.1 --- Introduction … --- p.55 / Chapter 4.2 --- Code Assignment and Graph Coloring --- p.55 / Chapter 4.3 --- Algorithm Description --- p.57 / Chapter 4.4 --- Results and Discussion --- p.59 / Chapter 4.5 --- Chapter Summary --- p.60 / Chapter CHAPTER 5 --- Fair and Efficient Transmission Scheduling --- p.64 / Chapter 5.1 --- Introduction --- p.65 / Chapter 5.2 --- The Scheduling Problem --- p.67 / Chapter 5.3 --- The Scheduling Algorithm --- p.68 / Chapter 5.4 --- Performance Analysis --- p.70 / Chapter 5.5 --- Results and Discussion --- p.72 / Chapter 5.6 --- Chapter Summary --- p.74 / Chapter CHAPTER 6 --- Staggered Multicast Protocol with Collision-Free Acknowledgement --- p.79 / Chapter 6.1 --- Introduction --- p.80 / Chapter 6.2 --- System Model --- p.83 / Chapter 6.3 --- Protocol Description --- p.84 / Chapter 6.4 --- Staggered Relay Broadcasting --- p.90 / Chapter 6.5 --- Simulation Results --- p.91 / Chapter 6.6 --- Chapter Summary --- p.92 / Chapter CHAPTER 7 --- Conclusion --- p.104 / Chapter 7.1 --- Summary --- p.105 / Chapter 7.2 --- Topics for Future Research --- p.107 / REFERENCES --- p.109

In this thesis, we present a theoretical investigation of reactive processes involving the HeH$^+$ molecular ion, with applications in laboratory and astrophysical plasma physics. We consider in particular two processes, which are the charge transfer in H + He$^+$ collisions at low energy from a molecular approach and the photodissociation of HeH$^+$. At the molecular level, the cross section is the basic quantity that has to be determined in order to achieve an understanding of reactive processes. Its calculation will be based on the description of the reactions using an emph{ab initio}, quantum mechanical approach. In this work, we will rely on the Born-Oppenheimer approximation, which allows the molecular motion to be separated into an electronic and a nuclear motion. The evaluation of cross sections then follows two steps. The first is the determination of the electronic structure of the molecule. We will calculate the adiabatic potential energy curves of the excited electronic states as well as the dipole matrix elements between these states. The non-adiabatic radial and rotational couplings, which result from the breakdown of the Born-Oppenheimer approximation, are also estimated. The second step is to solve the nuclear motion, which we achieve using a time-dependent method based on the propagation of wave packets on the coupled electronic states. A particular emphasis will be put on the importance of the excited states and of the non-adiabatic couplings in the description of reactive processes. In the treatment of the charge transfer reaction between H and He$^+$ in excited states, it is well known that the non-adiabatic radial couplings cannot be neglected. However, we will show that the inclusion of the non-adiabatic rotational couplings is also necessary in order to obtain accurate state-to-state cross sections. In the description of the photodissociation of HeH$^+$ from its ground state, we will show the influence of the excited states on the rate constant and the role of the non-adiabatic radial couplings in the determination of partial cross sections. We will also consider the possible astrophysical applications of the first triplet state of HeH$^+$. We will show that this state is metastable by evaluating its lifetime, and calculate the cross sections and rate constants for the photodissociation and radiative association of HeH$^+$ in this state.

The introduction of a new technology High Speed Downlink Packet Access (HSDPA) in the Release 5 of the 3GPP specifications raises the question about its performance capabilities. HSDPA is a promising technology which gives theoretical rates up to 14.4 Mbits. The main objective of this thesis is to discuss the system level performance of HSDPAMainly the thesis exploration focuses on the Packet Scheduler because it is the central entity of the HSDPA design. Due to its function, the Packet Scheduler has a direct impact on the HSDPA system performance. Similarly, it also determines the end user performance, and more specifically the relative performance between the users in the cell.The thesis analyzes several Packet Scheduling algorithms that can optimize the trade-off between system capacity and end user performance for the traffic classes targeted in this thesis.The performance evaluation of the algorithms in the HSDPA system are carried out under computer aided simulations that are assessed under realistic conditions to predict the results as precise on the algorithms efficiency. The simulation of the HSDPA system and the algorithms are coded in C/C++ language

Several demands relied on high-performance computing come up with the advanced technologies, like Satellite Imaging, Genetic Engineering, Global Weather Forecast, Nuclear Explosion Emulation, and in the meantime, the amount of data usually approaches the rank of Tera-Bytes, even Peta-Bytes. Besides, we need practical image application in our daily life, such as Game, 3D Display, High-Definition Video, etc. These requirements of high-performance computing are rigorous challenge to current devices. The performance of GPU (Graphic Processing Unit) is growing up rapidly in recent years. GPU doubles its computing power every year, which is far superior to CPU (Central Processing Unit) performance based on Moore¡¦s Law. Nowadays, the computing power of GPU on the single-precision floating-point operations is ten times than that of CPU. Furthermore, CUDA (Compute Unified Device Architecture) is a parallel computing architecture proposed by NVIDIA at 2007, and it is the first C-like language software development environment without Graphics API. In this research, we use GPU to assist network devices in filtering packets of the network flow, whose quantity is becoming more and more large. Due to the popularization of network, people pay attention to different types of network attacks or safety problems. Therefore, it is important to remove malicious packets from normal ones without degrading the network performance.

With the growing of Internet, people use network frequently. Many PC applications have moved to the network-based environment, such as text processing, calendar, photo management, and even user can develop applications on the network. Google is a company providing web services. Its popular services are search engine and gmail which attracts people by short response time and lots amount of data storage. It also charges businesses to place their own advertisements. Another hot social network is Facebook which is also a popular website. It processes huge instant messages and social relationships between users. The magic power of doing this depends on the new technique, Could Computing. Cloud computing has ability to keep high-performance processing and short response time, and its kernel components are distributed data storage and distributed data processing. Because of the new concept, there are fewer application, such as pattern searching and log file analysis, related to the cloud computing. Therefore, we use the technique to perform the packet analysis and packet dissection. The packet data are placed by distributed file system, and further process according to different requirements, which acts as IPS (Intrusion Protection System).

Packet classification plays an important role in next generation networks. Packet classification is important to fulfill the requirements for many applications including firewalls, multimedia services, intrusion detection services, and differentiated services to name just a few. Hardware solutions such as CAM/TCAM do not scale well in space. Current software-based packet classification algorithms exhibit relatively poor performance, prompting many researchers to concentrate on novel frameworks and architectures that employ both hardware and software components. In this thesis we propose two novel algorithms, Packet Classification with Incremental Update (PCIU) and Group Based Search packet classification Algorithm (GBSA), that are scalable and demonstrate excellent results in terms of preprocessing and classification. The PCIU algorithm is an innovative and efficient packet classification algorithm with a unique incremental update capability that demonstrates powerful results and is accessible for many different tasks and clients. The algorithm was further improved and made more available for a variety of applications through its implementation in hardware. Four such implementations are detailed and discussed in this thesis. A hardware accelerator based on an ESL approach, using Handel-C, resulted in a 22x faster classification than a pure software implementation running on a state of the art Xeon processor. An ASIP implementation achieved on average a 21x quicker classification. We also propose another novel algorithm, GBSA, for packet classification that is scalable, fast and efficient. On average the algorithm consumes 0.4 MB of memory for a 10k rule set. In the worst case scenario, the classification time per packet is 2 μs, and the pre-processing speed is 3M Rule/sec, based on a CPU operating at 3.4 GHz. The proposed algorithm was evaluated and compared to state-of-the-art techniques, such as RFC, HiCut, Tuple, and PCIU, using several standard benchmarks. The obtained results indicate that GBSA outperforms these algorithms in terms of speed, memory usage and pre-processing time. The algorithm, furthermore, was improved and made more accessible for a variety of applications through implementation in hardware. Three approaches using this algorithm are detailed and discussed in this thesis. The first approach was implemented using an Application Specific Instruction Processor (ASIP), while the others were pure RTL implementations using two different ESL flows (Impulse-C and Handel-C). The GBSA ASIP implementation achieved, on average, a 18x faster running speed than a pure software implementation operating on a Xeon processor. Conversely, the hardware accelerators (based on the ESL approaches) resulted in 9x faster processing.

No description available.

No description available.