841 Matching Results

Search Results

Advanced search parameters have been applied.

Data Transmission in Quantized Consensus

Description: In the world of networked system, average consensus is an important dimension of co-ordinate control and cooperation. Since the communication medium is digital, real value cannot be transmitted and we need to perform quantization before data transmission. But for the quantization, error is introduced in exact value and initial average is lost. Based on this limitation, my 16 bit quantization method (sending MSB in 1-4 cycle and MSB+LSB in 5th cycle) reduces error significantly and preserves initial average. Besides, it works on all types of graphs (star, complete, ring, random geometric graph). My other algorithm, distributing averaging algorithm (PQDA) with probabilistic quantization also works on random geometric graph, star, ring and slow co-herency graph. It shows significant reduced error and attain strict consensus.
Date: May 2013
Creator: Parvez, Imtiaz
Partner: UNT Libraries

Final report for the virtual channel encryptor laboratory directed research and development project

Description: A workstation with a single physical connection to a data communications network may have a requirement for simultaneous `virtual` communication channels to more than one destination. This report describes the development of techniques based on the Data Encryption Standard (DES) which encrypt these virtual channels to secure the data being transmitted against unauthorized access. A software module has been developed for the UNIX operating system using these techniques for encryption, and some development has also been done on a hardware device to be included between the workstation and network which can also provide these functions. The material presented in this report will be useful to those with a need to protect information in data communications systems from unauthorized access.
Date: August 1, 1997
Creator: Gibson, D.J. & Sarfaty, R.A.
Partner: UNT Libraries Government Documents Department

Ultra-low-power, long-wavelength photoreceivers for massively-parllel optical data links

Description: An ultra-low-power, long-wavelength photoreceiver based on InGaAs/InP heterojunction bipolar transistors is reported. The photoreceivers were designed for massively parallel applications where low-power density is necessary for both electrical and thermal reasons. We demonstrate two-dimensional, four-by-four arrays of photoreceivers for free-space optical data links that interface directly with 3.3 V CMOS ASICs and dissipate less than 12 mW/channel; lower power is possible. Propagation delays of {approx}1 nsec were measured and large signal operation of 800 Mbits/sec is demonstrated. The array is on a 500 {mu}m pitch and can be easily scaled to much higher density. The photoreceivers can be utilized in both free-space and guided-wave applications.
Date: March 1, 1996
Creator: Lovejoy, M.L.; Patrizi, G.A.; Enquist, P.M.; Carson, R.F.; Craft, D.C. & Shul, R.J.
Partner: UNT Libraries Government Documents Department

Final Report for the Scaled Asynchronous Transfer Mode (ATM) Encryption Laboratory Directed Research and Development Project

Description: This effort studied the integration of innovative methods of key management crypto synchronization, and key agility while scaling encryption speed. Viability of these methods for encryption of ATM cell payloads at the SONET OC- 192 data rate (10 Gb/s), and for operation at OC-48 rates (2.5 Gb/s) was shown. An SNL-Developed pipelined DES design was adapted for the encryption of ATM cells. A proof-of-principle prototype circuit board containing 11 Electronically Programmable Logic Devices (each holding the equivalent of 100,000 gates) was designed, built, and used to prototype a high speed encryptor.
Date: January 1, 1999
Creator: Pierson, L.G. & Witzke, E.L.
Partner: UNT Libraries Government Documents Department

Carrier sense data highway system. [Patent for a two-way Data Transmission System]

Description: A data transmission system is disclosed which includes a transmission medium which has a certain propagation delay time over its length. A number of data stations are successively coupled to the transmission medium for communicating with one another. Each of the data stations includes a transmitter for originating signals, each signal beginning with a carrier of a duration which is at least the propagation delay time of the transmission medium. Each data station also includes a receiver which receives other signals from other data stations and inhibits operation of the transmitter at the same data station when a carrier of another signal is received.
Date: April 30, 1981
Creator: Frankel, R.
Partner: UNT Libraries Government Documents Department

A First Look at Modern Enterprise Traffic

Description: While wide-area Internet traffic has been heavily studied for many years, the characteristics of traffic inside Internet enterprises remain almost wholly unexplored. Nearly all of the studies of enterprise traffic available in the literature are well over a decade old and focus on individual LANs rather than whole sites. In this paper we present a broad overview of internal enterprise traffic recorded at a medium-sized site. The packet traces span more than 100 hours, over which activity from a total of several thousand internal hosts appears. This wealth of data--which we are publicly releasing in anonymized form--spans a wide range of dimensions. While we cannot form general conclusions using data from a single site, and clearly this sort of data merits additional in-depth study in a number of ways, in this work we endeavor to characterize a number of the most salient aspects of the traffic. Our goal is to provide a first sense of ways in which modern enterprise traffic is similar to wide-area Internet traffic, and ways in which it is quite different.
Date: June 1, 2005
Creator: Pang, Ruoming; Mark Allman, Mark; Bennett, Mike; Lee, Jason; Paxson, Vern & Tierney, Brian
Partner: UNT Libraries Government Documents Department

The Federal Networking and Information Technology Research and Development Program: Funding Issues and Activities

Description: This report discusses the federal government's role in the country's information technology (IT) research and development (R&D) activities. The government's support of IT R&D began because it had an important interest in creating computers and software that would be capable of addressing the problems and issues the government needed to solve and study.
Date: April 16, 2007
Creator: Figliola, Patricia Moloney
Partner: UNT Libraries Government Documents Department

Distributed sensor networks with collective computation

Description: Simulations of a network of N sensors have been performed. The simulation space contains a number of sound sources and a large number of sensors. Each sensor is equipped with an omni-directional microphone and is capable of measuring only the time of arrival of a signal. Sensors are able to wirelessly transmit and receive packets of information, and have some computing power. The sensors were programmed to merge all information (received packets as well as local measurements) into a 'world view' for that node. This world view is then transmitted. In this way, information can slowly diffuse across the network. One node was monitored in the network as a proxy for when information had diffused across the network. Simulations demonstrated that the energy expended per sensor per time step was approximately independent of N.
Date: January 1, 2001
Creator: Lanman, D. R. (Douglas R.)
Partner: UNT Libraries Government Documents Department

Overview and Issues for Implementation of the Federal Cloud Computing Initiative: Implications for Federal Information Technology Reform Management

Description: This report explains what cloud computing is, including cloud deployment models and service models, discusses issues that should be considered when adopting cloud services, and presents the federal government's planning for IT reform.
Date: January 20, 2015
Creator: Figliola, Patricia Moloney & Fischer, Eric A.
Partner: UNT Libraries Government Documents Department

Compact, low-crosstalk, WDM filter elements for multimode ribbon fiber data links

Description: We have been developing the optical components for a source-routed wavelength division multiplexed (WDM) computer interconnect fabric that uses multi-mode fiber ribbon cable as the transmission medium. We are developing wavelength selectable VCSEL transmitters, interference filters, and a compact broadcast element. Here we report on key results from our interference filter development activities. Our WDM filter approach is based upon post-market machining of the commercially available molded plastic �MT� fiber ribbon connector. We use III-IV semiconductors grown by MBE or MOCVD as the filter materials. The high indices of our thin film materials enable us to use multimode fiber and maintain narrow passbands without the need for micro-optics. We have fabricated both 2-port and 3-port devices based upon this approach. Our current work focuses on 2-port WDM filters suitable for a broadcast and select architecture. Our single-cavity Fabry- Perot (FP) filters have demonstrated insertion losses of < 2 dB for 4 nm passbands. The maximum crosstalk suppression for the single-cavity FP filters is 18dB To improve crosstalk suppression beyond that attainable with the Lorentzian lineshapes of the single-cavity FP we have investigated some multiple-cavity Fabry-Perot (MC-FP) designs which have a spectral response with a flatter top and sharper passband edges. Filter passband edge sharpness can be quantified by the ratio of the filter 3 dB bandwidth to 18 dB bandwidth This ratio is 0.48 for our multi-cavity filter, three times sharper than the single-cavity FP devices. This device provides a 5 nm tolerance window for component wavelength variations (at 1 dB excess loss) and is suitable for 10 nm channel spacing with 23 dB crosstalk suppression between adjacent channels. The average insertion loss for the MC-l? devices is 1.6 dB. (Average of insertion losses for the 12 fibers in a filter module.) Our current MC-FP filters have a 3-dB width ...
Date: January 1, 1999
Creator: Deri, R J; Emanuel, M A; Garrett, H H; Krol, D M; Larson, M Pocha, M D; Lowry, M E et al.
Partner: UNT Libraries Government Documents Department

The Target Data Breach: Frequently Asked Questions

Description: This report answers some frequently asked questions about the Target (store) data breach, including what is known to have happened in the breach, and what costs may result. It also examines some of the broader issues common to data breaches, including how the payment system works, how cybersecurity costs are shared and allocated within the payment system, who bears the losses in such breaches more generally, what emerging cybersecurity technologies may help prevent them, and what role the government could play in encouraging their adoption, as well as some of the legislation that the 113th Congress has introduced to deal with these issues.
Date: April 22, 2014
Creator: Weiss, N. E. & Miller, Rena S.
Partner: UNT Libraries Government Documents Department

Overview and Issues for Implementation of the Federal Cloud Computing Initiative: Implications for Federal Information Technology Reform Management

Description: This report explains what cloud computing is -- including cloud deployment models and service models -- discusses issues that should be considered when adopting cloud services, and presents the federal government's planning for IT reform. It also provides information on assessments that have been conducted on agency cloud adoption and discusses both the challenges and drivers of cloud adoption. Finally, the report provides possible mechanisms for Congress to monitor agencies as they implement cloud computing.
Date: February 3, 2014
Creator: Figliola, Patricia Moloney & Fischer, Eric A.
Partner: UNT Libraries Government Documents Department

Performance Evaluation of MPLS on Quality of Service in Voice Over IP (VoIP) Networks

Description: The transmission of voice data over Internet Protocol (IP) networks is rapidly gaining acceptance in the field of networking. The major voice transmissions in the IP networks are involved in Internet telephony, which is also known as IP telephony or Voice Over IP (VoIP). VoIP is undergoing many enhancements to provide the end users with same quality as in the public switched telephone networks (PSTN). These enhancements are mostly required in quality of service (QoS) for the transmission of voice data over the IP networks. As with recent developments in the networking field, various protocols came into market to provide the QoS in IP networks - of them, multi protocol label switching (MPLS) is the most reliable and upcoming protocol for working on QoS. The problem of the thesis is to develop an IP-based virtual network, with end hosts and routers, implement MPLS on the network, and analyze its QoS for voice data transmission.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: December 2002
Creator: Chetty, Sharath
Partner: UNT Libraries

Wireless Mine-Wide Telecommunications Technology, Quarterly Report: October - December 2002

Description: We added data transmission to the through-the-earth communications system using quadrature synchronous detection. The results are adequate for computer-to-computer communication as well as for sensor data transmission. We added a feature to the in-mine communications system that allows a person to call an individual, rather than broadcasting, by dialing an identification number before speaking.
Date: January 2003
Creator: Meiksin, Zvi H.
Partner: UNT Libraries Government Documents Department

Development of Radar Navigation and Radio Data Transmission for Microhole Coiled Tubing Bottom Hole Assemblies

Description: This Final Technical Report summarizes the research and development (R&amp;D) work performed by Stolar Research Corporation (Stolar) under U.S. Department of Energy (DOE) Contract Number DE-FC26-04NT15477. This work involved the development of radar navigation and radio data transmission systems for integration with microhole coiled tubing bottom hole assemblies. Under this contract, Stolar designed, fabricated, and laboratory and field tested two advanced technologies of importance to the future growth of the U.S. oil and gas industry: (1) real-time measurement-while-drilling (MWD) for guidance and navigation of coiled tubing drilling in hydrocarbon reservoirs and (2) two-way inductive radio data transmission on coiled tubing for real-time, subsurface-to-surface data transmission. The operating specifications for these technologies are compatible with 3.5-inch boreholes drilled to a true vertical depth (TVD) of 5,000 feet, which is typical of coiled tubing drilling applications. These two technologies (i.e., the Stolar Data Transmission System and Drill String Radar) were developed into pre-commercial prototypes and tested successfully in simulated coiled tubing drilling conditions. Integration of these two technologies provides a real-time geosteering capability with extremely quick response times. Stolar is conducting additional work required to transition the Drill String Radar into a true commercial product. The results of this advanced development work should be an important step in the expanded commercialization of advanced coiled tubing microhole drilling equipment for use in U.S. hydrocarbon reservoirs.
Date: March 25, 2007
Creator: Stolarczyk, Larry G.; Stolarczyk, Gerald L.; Icerman, Larry; Howard, John & Tehrani, Hooman
Partner: UNT Libraries Government Documents Department

Dispersion-reduction technique using subcarrier multiplexing

Description: We have developed a novel dispersion-reduction technique using subcarrier multiplexing (SCM) which permits the transmission of multiple 2.5 Gbit/s data channels over hundreds of kilometers of conventional fiber-optic cable with negligible dispersion. Using a lithium niobate external modulator having a modulation bandwidth of 20 GHz, we are able to multiplex several high-speed data channels at a single wavelength. At the receiving end, we demultiplex the data and detect each channel using a 2-GHz bandwidth optical detector. All of the hardware in our system consists of off-the-shelf components and can be integrated to reduce the overall cost. We demonstrated our dispersion-reduction technique in a recent field trial by transmitting two 2.5 Gbit/s data channels over 90 km of commercially-installed single-mode fiber, followed by 210 km of spooled fiber. For comparison, we substituted the 300 km of fiber with equivalent optical attenuation. We also ran computer simulations to evaluate link behavior. Technical details and field trial results will be presented.
Date: October 18, 1995
Creator: Sargis, P. D.; Haigh, R. E. & McCammon, K. G.
Partner: UNT Libraries Government Documents Department

Low-power modular parallel photonic data links

Description: Many of the potential applications for parallel photonic data links could benefit from a bi-directional Optoelectronic Multi-Chip Module (OEMCM), where the optical transmitter, receiver, and first-level interface electronics are combined into a single package. It would be desirable for such a module to exhibit low power consumption, have a simple electronic interface that can operate at a variety of speeds, and possess a capability to use interchangeable optics for a variety of external connections. Here, we describe initial results for a parallel photonic link technology that exhibits those properties. This link uses high-efficiency, back-emitting, two-dimensional Vertical Cavity Surface-Emitting Laser (VCSEL) arrays operating at 980 nm. The lasers are matched, via integrated microlenses, to corresponding monolithically-integrated photoreceiver arrays that are constructed in a InGaAs/InP Heterojunction Bipolar Transistor (HBT) technology. In initial breadboard-level tests, the photonic data channels built with these devices have been demonstrated with direct (3.3 V) CMOS drive of the VCSELs and a corresponding CMOS interface at the photoreceiver outputs. These links have shown electrical power consumption as low as 42 mW per channel for a 50% average duty cycle while operating at 100 Mb/s.
Date: March 1, 1996
Creator: Carson, R.F.; Lovejoy, M.L.; Lear, K.L.; Warren, M.E.; Seigal, P.K.; Patrizi, G.A. et al.
Partner: UNT Libraries Government Documents Department

Security technologies and protocols for Asynchronous Transfer Mode networks

Description: Asynchronous Transfer Mode (ATM) is a new data communications technology that promises to integrate voice, video, and data traffic into a common network infrastructure. In order to fully utilize ATM`s ability to transfer real-time data at high rates, applications will start to access the ATM layer directly. As a result of this trend, security mechanisms at the ATM layer will be required. A number of research programs are currently in progress which seek to better understand the unique issues associated with ATM security. This paper describes some of these issues, and the approaches taken by various organizations in the design of ATM layer security mechanisms. Efforts within the ATM Forum to address the user communities need for ATM security are also described.
Date: June 1, 1996
Creator: Tarman, T.D.
Partner: UNT Libraries Government Documents Department

Performance analysis of ATM ABR service under self-similar traffic in the presence of background VBR traffic

Description: Recent empirical studies of traffic measurements of packet switched networks have demonstrated that actual network traffic is self-similar, or long range dependent, in nature. That is, the measured traffic is bursty over a wide range of time intervals. Furthermore, the emergence of high-speed network backbones demands the study of accurate models of aggregated traffic to assess network performance. This paper provides a method for generation of self-similar traffic, which can be used to drive network simulation models. The authors present the results of a simulation study of a two-node ATM network configuration that supports the ATM Forum`s Available Bit Rate (ABR) service. In this study, the authors compare the state of the queue at the source router at the edge of the ATM network under both Poisson and self-similar traffic loading. These findings indicate an order of magnitude increase in queue length for self-similar traffic loading as compared to Poisson loading. Moreover, when background VBR traffic is present, self-similar ABR traffic causes more congestion at the ATM switches than does Poisson traffic.
Date: May 1, 1996
Creator: Benke, G.; Brandt, J.; Chen, H.; Dastangoo, S. & Miller, G.J.
Partner: UNT Libraries Government Documents Department

The effects of user mobility on usage parameter control (UPC) in wireless ATM systems

Description: Wireless Asynchronous Transfer Mode (WATM) networks pose new traffic management problems. One example is the effect of user mobility on Usage Parameter Control (UPC). If the UPC algorithm resets after each handoff between wireless-cells, then users can cheat on their traffic contract. This paper derives explicit relationships between a user`s traffic parameters (Peak Cell Rate, Sustained Cell Rate and Maximum Burst Size), their transit time per wireless-cell, their maximum sustained cheating-rate and the Generic Cell Rate Algorithm`s (GCRA`s) Limit (L) parameter. It also shows that the GCRA can still effectively police Constant Bit Rate (CBR) traffic, but not some types of realistic Variable Bit Rate (VBR) traffic.
Date: July 1, 1997
Creator: Sholander, P.; Martinez, L.; Tolendino, L. & Mah, B.A.
Partner: UNT Libraries Government Documents Department

Writing World-Wide Web CGI scripts in the REXX language

Description: This talk is aimed at people who have experience with REXX and are interested in using it to write WWW CGI scripts. As part of this, the author describes several functions that are available in a library of REXX functions that simplify writing WWW CGI scripts. This library is freely available at //www.slac.standard.edu/slac/www/tool/cgi-rexx/.
Date: March 1, 1996
Creator: Cottrell, R.L.A.
Partner: UNT Libraries Government Documents Department