Quantum internet using code division multiple access

Science.gov (United States)

Zhang, Jing; Liu, Yu-xi; Özdemir, Şahin Kaya; Wu, Re-Bing; Gao, Feifei; Wang, Xiang-Bin; Yang, Lan; Nori, Franco

2013-01-01

A crucial open problem inS large-scale quantum networks is how to efficiently transmit quantum data among many pairs of users via a common data-transmission medium. We propose a solution by developing a quantum code division multiple access (q-CDMA) approach in which quantum information is chaotically encoded to spread its spectral content, and then decoded via chaos synchronization to separate different sender-receiver pairs. In comparison to other existing approaches, such as frequency division multiple access (FDMA), the proposed q-CDMA can greatly increase the information rates per channel used, especially for very noisy quantum channels. PMID:23860488

Wavelet based multicarrier code division multiple access ...

African Journals Online (AJOL)

This paper presents the study on Wavelet transform based Multicarrier Code Division Multiple Access (MC-CDMA) system for a downlink wireless channel. The performance of the system is studied for Additive White Gaussian Noise Channel (AWGN) and slowly varying multipath channels. The bit error rate (BER) versus ...

On the upgrade of an optical code division PON with a code-sense ethernet MAC protocol

NARCIS (Netherlands)

Huiszoon, B.; Waardt, de H.; Khoe, G.D.; Koonen, A.M.J.

2007-01-01

We propose, for the first time, optical code-sense multiple access / collision detection to upgrade an optical code division passive optical network with minor modifications to transparently deploy Ethernet (or packet) based services.

Diagonal Eigenvalue Unity (DEU) code for spectral amplitude coding-optical code division multiple access

Science.gov (United States)

Ahmed, Hassan Yousif; Nisar, K. S.

2013-08-01

Code with ideal in-phase cross correlation (CC) and practical code length to support high number of users are required in spectral amplitude coding-optical code division multiple access (SAC-OCDMA) systems. SAC systems are getting more attractive in the field of OCDMA because of its ability to eliminate the influence of multiple access interference (MAI) and also suppress the effect of phase induced intensity noise (PIIN). In this paper, we have proposed new Diagonal Eigenvalue Unity (DEU) code families with ideal in-phase CC based on Jordan block matrix with simple algebraic ways. Four sets of DEU code families based on the code weight W and number of users N for the combination (even, even), (even, odd), (odd, odd) and (odd, even) are constructed. This combination gives DEU code more flexibility in selection of code weight and number of users. These features made this code a compelling candidate for future optical communication systems. Numerical results show that the proposed DEU system outperforms reported codes. In addition, simulation results taken from a commercial optical systems simulator, Virtual Photonic Instrument (VPI™) shown that, using point to multipoint transmission in passive optical network (PON), DEU has better performance and could support long span with high data rate.

Optical code division multiple access secure communications systems with rapid reconfigurable polarization shift key user code

Science.gov (United States)

Gao, Kaiqiang; Wu, Chongqing; Sheng, Xinzhi; Shang, Chao; Liu, Lanlan; Wang, Jian

2015-09-01

An optical code division multiple access (OCDMA) secure communications system scheme with rapid reconfigurable polarization shift key (Pol-SK) bipolar user code is proposed and demonstrated. Compared to fix code OCDMA, by constantly changing the user code, the performance of anti-eavesdropping is greatly improved. The Pol-SK OCDMA experiment with a 10 Gchip/s user code and a 1.25 Gb/s user data of payload has been realized, which means this scheme has better tolerance and could be easily realized.

Development of authentication code for multi-access optical code division multiplexing based quantum key distribution

Science.gov (United States)

Taiwo, Ambali; Alnassar, Ghusoon; Bakar, M. H. Abu; Khir, M. F. Abdul; Mahdi, Mohd Adzir; Mokhtar, M.

2018-05-01

One-weight authentication code for multi-user quantum key distribution (QKD) is proposed. The code is developed for Optical Code Division Multiplexing (OCDMA) based QKD network. A unique address assigned to individual user, coupled with degrading probability of predicting the source of the qubit transmitted in the channel offer excellent secure mechanism against any form of channel attack on OCDMA based QKD network. Flexibility in design as well as ease of modifying the number of users are equally exceptional quality presented by the code in contrast to Optical Orthogonal Code (OOC) earlier implemented for the same purpose. The code was successfully applied to eight simultaneous users at effective key rate of 32 bps over 27 km transmission distance.

Utility subroutine package used by Applied Physics Division export codes

International Nuclear Information System (INIS)

Adams, C.H.; Derstine, K.L.; Henryson, H. II; Hosteny, R.P.; Toppel, B.J.

1983-04-01

This report describes the current state of the utility subroutine package used with codes being developed by the staff of the Applied Physics Division. The package provides a variety of useful functions for BCD input processing, dynamic core-storage allocation and managemnt, binary I/0 and data manipulation. The routines were written to conform to coding standards which facilitate the exchange of programs between different computers

Performance enhancement of optical code-division multiple-access systems using transposed modified Walsh code

Science.gov (United States)

Sikder, Somali; Ghosh, Shila

2018-02-01

This paper presents the construction of unipolar transposed modified Walsh code (TMWC) and analysis of its performance in optical code-division multiple-access (OCDMA) systems. Specifically, the signal-to-noise ratio, bit error rate (BER), cardinality, and spectral efficiency were investigated. The theoretical analysis demonstrated that the wavelength-hopping time-spreading system using TMWC was robust against multiple-access interference and more spectrally efficient than systems using other existing OCDMA codes. In particular, the spectral efficiency was calculated to be 1.0370 when TMWC of weight 3 was employed. The BER and eye pattern for the designed TMWC were also successfully obtained using OptiSystem simulation software. The results indicate that the proposed code design is promising for enhancing network capacity.

Polarization diversity scheme on spectral polarization coding optical code-division multiple-access network

Science.gov (United States)

Yen, Chih-Ta; Huang, Jen-Fa; Chang, Yao-Tang; Chen, Bo-Hau

2010-12-01

We present an experiment demonstrating the spectral-polarization coding optical code-division multiple-access system introduced with a nonideal state of polarization (SOP) matching conditions. In the proposed system, the encoding and double balanced-detection processes are implemented using a polarization-diversity scheme. Because of the quasiorthogonality of Hadamard codes combining with array waveguide grating routers and a polarization beam splitter, the proposed codec pair can encode-decode multiple code words of Hadamard code while retaining the ability for multiple-access interference cancellation. The experimental results demonstrate that when the system is maintained with an orthogonal SOP for each user, an effective reduction in the phase-induced intensity noise is obtained. The analytical SNR values are found to overstate the experimental results by around 2 dB when the received effective power is large. This is mainly limited by insertion losses of components and a nonflattened optical light source. Furthermore, the matching conditions can be improved by decreasing nonideal influences.

Inclusive bit error rate analysis for coherent optical code-division multiple-access system

Science.gov (United States)

Katz, Gilad; Sadot, Dan

2002-06-01

Inclusive noise and bit error rate (BER) analysis for optical code-division multiplexing (OCDM) using coherence techniques is presented. The analysis contains crosstalk calculation of the mutual field variance for different number of users. It is shown that the crosstalk noise depends deeply on the receiver integration time, the laser coherence time, and the number of users. In addition, analytical results of the power fluctuation at the received channel due to the data modulation at the rejected channels are presented. The analysis also includes amplified spontaneous emission (ASE)-related noise effects of in-line amplifiers in a long-distance communication link.

Measurements of stimulated-Raman-scattering-induced tilt in spectral-amplitude-coding optical code-division multiple-access systems

Science.gov (United States)

Al-Qazwini, Zaineb A. T.; Abdullah, Mohamad K.; Mokhtar, Makhfudzah B.

2009-01-01

We measure the stimulated Raman scattering (SRS)-induced tilt in spectral-amplitude-coding optical code-division multiple-access (SAC-OCDMA) systems as a function of system main parameters (transmission distance, power per chip, and number of users) via computer simulations. The results show that SRS-induced tilt significantly increases as transmission distance, power per chip, or number of users grows.

China Dimensions Data Collection: GuoBiao (GB) Codes for the Administrative Divisions of the Peoples Republic of China

Data.gov (United States)

National Aeronautics and Space Administration — GuoBiao (GB) Codes for the Administrative Divisions of the People's Republic of China consists of geographic codes for the administrative divisions of China. The...

Ultrafast all-optical code-division multiple-access networks

Science.gov (United States)

Kwong, Wing C.; Prucnal, Paul R.; Liu, Yanming

1992-12-01

In optical code-division multiple access (CDMA), the architecture of optical encoders/decoders is another important factor that needs to be considered, besides the correlation properties of those already extensively studied optical codes. The architecture of optical encoders/decoders affects, for example, the amount of power loss and length of optical delays that are associated with code sequence generation and correlation, which, in turn, affect the power budget, size, and cost of an optical CDMA system. Various CDMA coding architectures are studied in the paper. In contrast to the encoders/decoders used in prime networks (i.e., prime encodes/decoders), which generate, select, and correlate code sequences by a parallel combination of fiber-optic delay-lines, and in 2n networks (i.e., 2n encoders/decoders), which generate and correlate code sequences by a serial combination of 2 X 2 passive couplers and fiber delays with sequence selection performed in a parallel fashion, the modified 2n encoders/decoders generate, select, and correlate code sequences by a serial combination of directional couplers and delays. The power and delay- length requirements of the modified 2n encoders/decoders are compared to that of the prime and 2n encoders/decoders. A 100 Mbit/s optical CDMA experiment in free space demonstrating the feasibility of the all-serial coding architecture using a serial combination of 50/50 beam splitters and retroreflectors at 10 Tchip/s (i.e., 100,000 chip/bit) with 100 fs laser pulses is reported.

Experimental demonstration of 2.5 Gbit/S incoherent two-dimensional optical code division multiple access system

International Nuclear Information System (INIS)

Glesk, I.; Baby, V.; Bres, C.-S.; Xu, L.; Rand, D.; Prucnal, P.R.

2004-01-01

We demonstrated error-free operation of 4 simultaneous users in a fast frequency-hopping time-spreading optical code division multiple access system operating at 2.5 Gbit/s a Star architecture. Effective power penalty was ≤0.5dB. Novel optical code division multiple access receiver based on Terahertz Optical Asymmetric Demultiplexer was demonstrated to eliminate multiple access interference (Authors)

Average Likelihood Methods of Classification of Code Division Multiple Access (CDMA)

Science.gov (United States)

2016-05-01

subject to code matrices that follows the structure given by (113). [⃗ yR y⃗I ] = √ Es 2L [ GR1 −GI1 GI2 GR2 ] [ QR −QI QI QR ] [⃗ bR b⃗I ] + [⃗ nR n⃗I... QR ] [⃗ b+ b⃗− ] + [⃗ n+ n⃗− ] (115) The average likelihood for type 4 CDMA (116) is a special case of type 1 CDMA with twice the code length and...AVERAGE LIKELIHOOD METHODS OF CLASSIFICATION OF CODE DIVISION MULTIPLE ACCESS (CDMA) MAY 2016 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE

Spatial-phase code-division multiple-access system with multiplexed Fourier holography switching for reconfigurable optical interconnection

Science.gov (United States)

Takasago, Kazuya; Takekawa, Makoto; Shirakawa, Atsushi; Kannari, Fumihiko

2000-05-01

A new, to our knowledge, space-variant optical interconnection system based on a spatial-phase code-division multiple-access technique with multiplexed Fourier holography is described. In this technique a signal beam is spread over wide spatial frequencies by an M -sequence pseudorandom phase code. At a receiver side a selected signal beam is properly decoded, and at the same time its spatial pattern is shaped with a Fourier hologram, which is recorded by light that is encoded with the same M -sequence phase mask as the desired signal beam and by light whose spatial beam pattern is shaped to a signal routing pattern. Using the multiplexed holography, we can simultaneously route multisignal flows into individually specified receiver elements. The routing pattern can also be varied by means of switching the encoding phase code or replacing the hologram. We demonstrated a proof-of-principle experiment with a doubly multiplexed hologram that enables simultaneous routing of two signal beams. Using a numerical model, we showed that the proposed scheme can manage more than 250 routing patterns for one signal flow with one multiplexed hologram at a signal-to-noise ratio of 5.

Secure Communications in High Speed Fiber Optical Networks Using Code Division Multiple Access (CDMA) Transmission

Energy Technology Data Exchange (ETDEWEB)

Han, I; Bond, S; Welty, R; Du, Y; Yoo, S; Reinhardt, C; Behymer, E; Sperry, V; Kobayashi, N

2004-02-12

This project is focused on the development of advanced components and system technologies for secure data transmission on high-speed fiber optic data systems. This work capitalizes on (1) a strong relationship with outstanding faculty at the University of California-Davis who are experts in high speed fiber-optic networks, (2) the realization that code division multiple access (CDMA) is emerging as a bandwidth enhancing technique for fiber optic networks, (3) the realization that CDMA of sufficient complexity forms the basis for almost unbreakable one-time key transmissions, (4) our concepts for superior components for implementing CDMA, (5) our expertise in semiconductor device processing and (6) our Center for Nano and Microtechnology, which is where the majority of the experimental work was done. Here we present a novel device concept, which will push the limits of current technology, and will simultaneously solve system implementation issues by investigating new state-of-the-art fiber technologies. This will enable the development of secure communication systems for the transmission and reception of messages on deployed commercial fiber optic networks, through the CDMA phase encoding of broad bandwidth pulses. CDMA technology has been developed as a multiplexing technology, much like wavelength division multiplexing (WDM) or time division multiplexing (TDM), to increase the potential number of users on a given communication link. A novel application of the techniques created for CDMA is to generate secure communication through physical layer encoding. Physical layer encoding devices are developed which utilize semiconductor waveguides with fast carrier response times to phase encode spectral components of a secure signal. Current commercial technology, most commonly a spatial light modulator, allows phase codes to be changed at rates of only 10's of Hertz ({approx}25ms response). The use of fast (picosecond to nanosecond) carrier dynamics of semiconductors

Free-space optical code-division multiple-access system design

Science.gov (United States)

Jeromin, Lori L.; Kaufmann, John E.; Bucher, Edward A.

1993-08-01

This paper describes an optical direct-detection multiple access communications system for free-space satellite networks utilizing code-division multiple-access (CDMA) and forward error correction (FEC) coding. System performance is characterized by how many simultaneous users operating at data rate R can be accommodated in a signaling bandwidth W. The performance of two CDMA schemes, optical orthogonal codes (OOC) with FEC and orthogonal convolutional codes (OCC), is calculated and compared to information-theoretic capacity bounds. The calculations include the effects of background and detector noise as well as nonzero transmitter extinction ratio and power imbalance among users. A system design for 10 kbps multiple-access communications between low-earth orbit satellites is given. With near- term receiver technology and representative system losses, a 15 W peak-power transmitter provides 10-6 BER performance with seven interfering users and full moon background in the receiver FOV. The receiver employs an array of discrete wide-area avalanche photodiodes (APD) for wide field of view coverage. Issues of user acquisition and synchronization, implementation technology, and system scalability are also discussed.

System performances of optical space code-division multiple-access-based fiber-optic two-dimensional parallel data link.

Science.gov (United States)

Nakamura, M; Kitayama, K

1998-05-10

Optical space code-division multiple access is a scheme to multiplex and link data between two-dimensional processors such as smart pixels and spatial light modulators or arrays of optical sources like vertical-cavity surface-emitting lasers. We examine the multiplexing characteristics of optical space code-division multiple access by using optical orthogonal signature patterns. The probability density function of interference noise in interfering optical orthogonal signature patterns is calculated. The bit-error rate is derived from the result and plotted as a function of receiver threshold, code length, code weight, and number of users. Furthermore, we propose a prethresholding method to suppress the interference noise, and we experimentally verify that the method works effectively in improving system performance.

Simulative Investigation on Spectral Efficiency of Unipolar Codes based OCDMA System using Importance Sampling Technique

Science.gov (United States)

Farhat, A.; Menif, M.; Rezig, H.

2013-09-01

This paper analyses the spectral efficiency of Optical Code Division Multiple Access (OCDMA) system using Importance Sampling (IS) technique. We consider three configurations of OCDMA system namely Direct Sequence (DS), Spectral Amplitude Coding (SAC) and Fast Frequency Hopping (FFH) that exploits the Fiber Bragg Gratings (FBG) based encoder/decoder. We evaluate the spectral efficiency of the considered system by taking into consideration the effect of different families of unipolar codes for both coherent and incoherent sources. The results show that the spectral efficiency of OCDMA system with coherent source is higher than the incoherent case. We demonstrate also that DS-OCDMA outperforms both others in terms of spectral efficiency in all conditions.

Performance enhancement of successive interference cancellation scheme based on spectral amplitude coding for optical code-division multiple-access systems using Hadamard codes

Science.gov (United States)

Eltaif, Tawfig; Shalaby, Hossam M. H.; Shaari, Sahbudin; Hamarsheh, Mohammad M. N.

2009-04-01

A successive interference cancellation scheme is applied to optical code-division multiple-access (OCDMA) systems with spectral amplitude coding (SAC). A detailed analysis of this system, with Hadamard codes used as signature sequences, is presented. The system can easily remove the effect of the strongest signal at each stage of the cancellation process. In addition, simulation of the prose system is performed in order to validate the theoretical results. The system shows a small bit error rate at a large number of active users compared to the SAC OCDMA system. Our results reveal that the proposed system is efficient in eliminating the effect of the multiple-user interference and in the enhancement of the overall performance.

Testbed for Multi-Wavelength Optical Code Division Multiplexing Based on Passive Linear Unitary Filters

National Research Council Canada - National Science Library

Yablonovitch, Eli

2000-01-01

.... The equipment purchased under this grant has permitted UCLA to purchase a number of broad-band optical components, including especially some unique code division multiplexing filters that permitted...

Image transmission in multicore-fiber code-division multiple access network

Science.gov (United States)

Yang, Guu-Chang; Kwong, Wing C.

1997-01-01

Recently, two-dimensional (2-D) signature patterns were proposed to encode binary digitized image pixels in optical code-division multiple-access (CDMA) networks with 'multicore' fiber. The new technology enables parallel transmission and simultaneous access of 2-D images in multiple-access environment, where these signature patterns are defined as optical orthogonal signature pattern codes (OOSPCs). However, previous work on OOSPCs assumed that the weight of each signature pattern was the same. In this paper, we construct a new family of OOSPCs with the removal of this assumption. Since varying the weight of a user's signature pattern affects that user's performance, this approach is useful for CDMA optical systems with multiple performance requirements.

High-Speed Turbo-TCM-Coded Orthogonal Frequency-Division Multiplexing Ultra-Wideband Systems

Directory of Open Access Journals (Sweden)

Wang Yanxia

2006-01-01

Full Text Available One of the UWB proposals in the IEEE P802.15 WPAN project is to use a multiband orthogonal frequency-division multiplexing (OFDM system and punctured convolutional codes for UWB channels supporting a data rate up to 480 Mbps. In this paper, we improve the proposed system using turbo TCM with QAM constellation for higher data rate transmission. We construct a punctured parity-concatenated trellis codes, in which a TCM code is used as the inner code and a simple parity-check code is employed as the outer code. The result shows that the system can offer a much higher spectral efficiency, for example, 1.2 Gbps, which is 2.5 times higher than the proposed system. We identify several essential requirements to achieve the high rate transmission, for example, frequency and time diversity and multilevel error protection. Results are confirmed by density evolution.

Performance analysis of multiple interference suppression over asynchronous/synchronous optical code-division multiple-access system based on complementary/prime/shifted coding scheme

Science.gov (United States)

Nieh, Ta-Chun; Yang, Chao-Chin; Huang, Jen-Fa

2011-08-01

A complete complementary/prime/shifted prime (CPS) code family for the optical code-division multiple-access (OCDMA) system is proposed. Based on the ability of complete complementary (CC) code, the multiple-access interference (MAI) can be suppressed and eliminated via spectral amplitude coding (SAC) OCDMA system under asynchronous/synchronous transmission. By utilizing the shifted prime (SP) code in the SAC scheme, the hardware implementation of encoder/decoder can be simplified with a reduced number of optical components, such as arrayed waveguide grating (AWG) and fiber Bragg grating (FBG). This system has a superior performance as compared to previous bipolar-bipolar coding OCDMA systems.

Cascaded holographic polymer reflection grating filters for optical-code-division multiple-access applications.

Science.gov (United States)

Kostuk, Raymond K; Maeda, Wendi; Chen, Chia-Hung; Djordjevic, Ivan; Vasic, Bane

2005-12-10

We evaluate the use of edge-illuminated holographic Bragg filters formed in phenanthrenequinone-doped poly(methyl methacrylate) for optical-code-division multiple-access (OCDMA) coding and decoding applications. Experimental cascaded Bragg filters are formed to select two different wavelengths with a fixed distance between the gratings and are directly coupled to a fiber-measurement system. The configuration and tolerances of the cascaded gratings are shown to be practical for time-wavelength OCDMA applications.

Channel coding techniques for wireless communications

CERN Document Server

Deergha Rao, K

2015-01-01

The book discusses modern channel coding techniques for wireless communications such as turbo codes, low-density parity check (LDPC) codes, space–time (ST) coding, RS (or Reed–Solomon) codes and convolutional codes. Many illustrative examples are included in each chapter for easy understanding of the coding techniques. The text is integrated with MATLAB-based programs to enhance the understanding of the subject’s underlying theories. It includes current topics of increasing importance such as turbo codes, LDPC codes, Luby transform (LT) codes, Raptor codes, and ST coding in detail, in addition to the traditional codes such as cyclic codes, BCH (or Bose–Chaudhuri–Hocquenghem) and RS codes and convolutional codes. Multiple-input and multiple-output (MIMO) communications is a multiple antenna technology, which is an effective method for high-speed or high-reliability wireless communications. PC-based MATLAB m-files for the illustrative examples are provided on the book page on Springer.com for free dow...

Survey Of Lossless Image Coding Techniques

Science.gov (United States)

Melnychuck, Paul W.; Rabbani, Majid

1989-04-01

Many image transmission/storage applications requiring some form of data compression additionally require that the decoded image be an exact replica of the original. Lossless image coding algorithms meet this requirement by generating a decoded image that is numerically identical to the original. Several lossless coding techniques are modifications of well-known lossy schemes, whereas others are new. Traditional Markov-based models and newer arithmetic coding techniques are applied to predictive coding, bit plane processing, and lossy plus residual coding. Generally speaking, the compression ratio offered by these techniques are in the area of 1.6:1 to 3:1 for 8-bit pictorial images. Compression ratios for 12-bit radiological images approach 3:1, as these images have less detailed structure, and hence, their higher pel correlation leads to a greater removal of image redundancy.

Reduction of the near-far effect in mobile communication systems with Code-Division Multiple-Access

Science.gov (United States)

Purchla, Magdalena

2006-02-01

In this paper the basic methods for reducing Multiple Access Interference (MAI) and combating the near-far effect in Direct-Sequence Code-Division Multiple-Access (DS-CDMA) mobile communication systems are presented. MAI and the near-far effect are inevitable in DS-CDMA systems with quasi-orthogonal spreading sequences. An effective method of reducing MAI can increase the capacity of the system that is why so many researchers are working in this field. In this article three most important techniques of decreasing MAI are presented: power control, multiuser detection and space-time processing. There is a short introduction to each topic and one or more examples found in literature of algorithms suitable for practical applications (although not all algorithms are yet used in existing systems).

Filter multiplexing by use of spatial Code Division Multiple Access approach.

Science.gov (United States)

Solomon, Jonathan; Zalevsky, Zeev; Mendlovic, David; Monreal, Javier Garcia

2003-02-10

The increasing popularity of optical communication has also brought a demand for a broader bandwidth. The trend, naturally, was to implement methods from traditional electronic communication. One of the most effective traditional methods is Code Division Multiple Access. In this research, we suggest the use of this approach for spatial coding applied to images. The approach is to multiplex several filters into one plane while keeping their mutual orthogonality. It is shown that if the filters are limited by their bandwidth, the output of all the filters can be sampled in the original image resolution and fully recovered through an all-optical setup. The theoretical analysis of such a setup is verified in an experimental demonstration.

Fiber Bragg grating for spectral phase optical code-division multiple-access encoding and decoding

Science.gov (United States)

Fang, Xiaohui; Wang, Dong-Ning; Li, Shichen

2003-08-01

A new method for realizing spectral phase optical code-division multiple-access (OCDMA) coding based on step chirped fiber Bragg gratings (SCFBGs) is proposed and the corresponding encoder/decoder is presented. With this method, a mapping code is introduced for the m-sequence address code and the phase shift can be inserted into the subgratings of the SCFBG according to the mapping code. The transfer matrix method together with Fourier transform is used to investigate the characteristics of the encoder/decoder. The factors that influence the correlation property of the encoder/decoder, including index modulation and bandwidth of the subgrating, are identified. The system structure is simple and good correlation output can be obtained. The performance of the OCDMA system based on SCFBGs has been analyzed.

Tailoring Chirped Moiré Fiber Bragg Gratings for Wavelength-Division-Multiplexing and Optical Code-Division Multiple-Access Applications

Science.gov (United States)

Chen, Lawrence R.; Smith, Peter W. E.

The design and fabrication of chirped Moiré fiber Bragg gratings (CMGs) are presented, which can be used in either (1) transmission as passband filters for providing wavelength selectivity in wavelength-division-multiplexed (WDM) systems or (2) reflection as encoding/decoding elements to decompose short broadband pulses in both wavelength and time in order to implement an optical code-division multiple-access (OCDMA) system. In transmission, the fabricated CMGs have single or multiple flattened passbands ( 12 dB isolation and near constant in-band group delay. It is shown that these filters do not produce any measurable dispersion-induced power penalties when used to provide wavelength selectivity in 2.5 Gbit/s systems. It is also demonstrated how CMGs can be used in reflection to encode/decode short pulses from a wavelength-tunable mode-locked Er-doped fiber laser.

Distributed magnetic field positioning system using code division multiple access

Science.gov (United States)

Prigge, Eric A. (Inventor)

2003-01-01

An apparatus and methods for a magnetic field positioning system use a fundamentally different, and advantageous, signal structure and multiple access method, known as Code Division Multiple Access (CDMA). This signal architecture, when combined with processing methods, leads to advantages over the existing technologies, especially when applied to a system with a large number of magnetic field generators (beacons). Beacons at known positions generate coded magnetic fields, and a magnetic sensor measures a sum field and decomposes it into component fields to determine the sensor position and orientation. The apparatus and methods can have a large `building-sized` coverage area. The system allows for numerous beacons to be distributed throughout an area at a number of different locations. A method to estimate position and attitude, with no prior knowledge, uses dipole fields produced by these beacons in different locations.

Catalogue of nuclear fusion codes - 1976

International Nuclear Information System (INIS)

1976-10-01

A catalogue is presented of the computer codes in nuclear fusion research developed by JAERI, Division of Thermonuclear Fusion Research and Division of Large Tokamak Development in particular. It contains a total of about 100 codes under the categories: Atomic Process, Data Handling, Experimental Data Processing, Engineering, Input and Output, Special Languages and Their Application, Mathematical Programming, Miscellaneous, Numerical Analysis, Nuclear Physics, Plasma Physics and Fusion Research, Plasma Simulation and Numerical Technique, Reactor Design, Solid State Physics, Statistics, and System Program. (auth.)

Adaptable recursive binary entropy coding technique

Science.gov (United States)

Kiely, Aaron B.; Klimesh, Matthew A.

2002-07-01

We present a novel data compression technique, called recursive interleaved entropy coding, that is based on recursive interleaving of variable-to variable length binary source codes. A compression module implementing this technique has the same functionality as arithmetic coding and can be used as the engine in various data compression algorithms. The encoder compresses a bit sequence by recursively encoding groups of bits that have similar estimated statistics, ordering the output in a way that is suited to the decoder. As a result, the decoder has low complexity. The encoding process for our technique is adaptable in that each bit to be encoded has an associated probability-of-zero estimate that may depend on previously encoded bits; this adaptability allows more effective compression. Recursive interleaved entropy coding may have advantages over arithmetic coding, including most notably the admission of a simple and fast decoder. Much variation is possible in the choice of component codes and in the interleaving structure, yielding coder designs of varying complexity and compression efficiency; coder designs that achieve arbitrarily small redundancy can be produced. We discuss coder design and performance estimation methods. We present practical encoding and decoding algorithms, as well as measured performance results.

Impact of optical hard limiter on the performance of an optical overlapped-code division multiple access system

Science.gov (United States)

Inaty, Elie; Raad, Robert; Tablieh, Nicole

2011-08-01

Throughout this paper, a closed form expression of the multiple access interference (MAI) limited bit error rate (BER) is provided for the multiwavelength optical code-division multiple-access system when the system is working above the nominal transmission rate limit imposed by the passive encoding-decoding operation. This system is known in literature as the optical overlapped code division multiple access (OV-CDMA) system. A unified analytical framework is presented emphasizing the impact of optical hard limiter (OHL) on the BER performance of such a system. Results show that the performance of the OV-CDMA system may be highly improved when using OHL preprocessing at the receiver side.

Novel security enhancement technique against eavesdropper for OCDMA system using 2-D modulation format with code switching scheme

Science.gov (United States)

Singh, Simranjit; Kaur, Ramandeep; Singh, Amanvir; Kaler, R. S.

2015-03-01

In this paper, security of the spectrally encoded-optical code division multiplexed access (OCDMA) system is enhanced by using 2-D (orthogonal) modulation technique. This is an effective approach for simultaneous improvement of the system capacity and security. Also, the results show that the hybrid modulation technique proved to be a better option to enhance the data confidentiality at higher data rates using minimum utilization of bandwidth in a multiuser environment. Further, the proposed system performance is compared with the current state-of-the-art OCDMA schemes.

Preliminary In-vivo Results For Spatially Coded Synthetic Transmit Aperture Ultrasound Based On Frequency Division

DEFF Research Database (Denmark)

Gran, Fredrik; Hansen, Kristoffer Lindskov; Jensen, Jørgen Arendt

2006-01-01

This paper investigates the possibility of using spatial coding based on frequency division for in-vivo synthetic transmit aperture (STA) ultrasound imaging. When using spatial encoding for STA, it is possible to use several transmitters simultaneously and separate the signals at the receiver....... This increases the maximum transmit power compared to conventional STA, where only one transmitter can be active. The signal-to-noise-ratio can therefore he increased and better penetration can be obtained. For frequency division, the coding is achieved by designing a number of transmit waveforms with disjoint...... spectral support, spanning the passband of the ultrasound transducer. The signals can therefore he separated at the receiver using matched filtering. The method is tested using a commercial linear array transducer with a center frequency of 9 MHz and 68% fractional bandwidth. In this paper, the transmit...

Dynamic divisive normalization predicts time-varying value coding in decision-related circuits.

Science.gov (United States)

Louie, Kenway; LoFaro, Thomas; Webb, Ryan; Glimcher, Paul W

2014-11-26

Normalization is a widespread neural computation, mediating divisive gain control in sensory processing and implementing a context-dependent value code in decision-related frontal and parietal cortices. Although decision-making is a dynamic process with complex temporal characteristics, most models of normalization are time-independent and little is known about the dynamic interaction of normalization and choice. Here, we show that a simple differential equation model of normalization explains the characteristic phasic-sustained pattern of cortical decision activity and predicts specific normalization dynamics: value coding during initial transients, time-varying value modulation, and delayed onset of contextual information. Empirically, we observe these predicted dynamics in saccade-related neurons in monkey lateral intraparietal cortex. Furthermore, such models naturally incorporate a time-weighted average of past activity, implementing an intrinsic reference-dependence in value coding. These results suggest that a single network mechanism can explain both transient and sustained decision activity, emphasizing the importance of a dynamic view of normalization in neural coding. Copyright © 2014 the authors 0270-6474/14/3416046-12$15.00/0.

Time-division optical interconnects for local-area and micro-area networks

Science.gov (United States)

Krol, Mark F.; Boncek, Raymond K.; Johns, Steven T.; Stacy, John L.

1991-12-01

This report describes the development of an optical Time-Division Multiple-Access (TDMA) interconnect suitable for applications in local-area and micro-area networks. The advantages of using time-division techniques instead of frequency-division, wavelength-division, or code-division techniques in a shared-medium environment are discussed in detail. Furthermore, a detailed description of the TDMA architecture is presented along with various experiments pertaining to the actual components needed to implement the system. Finally, experimental data is presented for an actual optical TDMA test bed. The experimental data demonstrates the feasibility of the architecture, and shows that currently the system has the capability to accommodate up to 50 channels. The bit-error-rate per channel was measured to be less than 10(exp -9) for pseudo-random bit-sequences.

Huffman-based code compression techniques for embedded processors

KAUST Repository

Bonny, Mohamed Talal

2010-09-01

The size of embedded software is increasing at a rapid pace. It is often challenging and time consuming to fit an amount of required software functionality within a given hardware resource budget. Code compression is a means to alleviate the problem by providing substantial savings in terms of code size. In this article we introduce a novel and efficient hardware-supported compression technique that is based on Huffman Coding. Our technique reduces the size of the generated decoding table, which takes a large portion of the memory. It combines our previous techniques, Instruction Splitting Technique and Instruction Re-encoding Technique into new one called Combined Compression Technique to improve the final compression ratio by taking advantage of both previous techniques. The instruction Splitting Technique is instruction set architecture (ISA)-independent. It splits the instructions into portions of varying size (called patterns) before Huffman coding is applied. This technique improves the final compression ratio by more than 20% compared to other known schemes based on Huffman Coding. The average compression ratios achieved using this technique are 48% and 50% for ARM and MIPS, respectively. The Instruction Re-encoding Technique is ISA-dependent. It investigates the benefits of reencoding unused bits (we call them reencodable bits) in the instruction format for a specific application to improve the compression ratio. Reencoding those bits can reduce the size of decoding tables by up to 40%. Using this technique, we improve the final compression ratios in comparison to the first technique to 46% and 45% for ARM and MIPS, respectively (including all overhead that incurs). The Combined Compression Technique improves the compression ratio to 45% and 42% for ARM and MIPS, respectively. In our compression technique, we have conducted evaluations using a representative set of applications and we have applied each technique to two major embedded processor architectures

A reflexive exploration of two qualitative data coding techniques

Directory of Open Access Journals (Sweden)

Erik Blair

2016-01-01

Full Text Available In an attempt to help find meaning within qualitative data, researchers commonly start by coding their data. There are a number of coding systems available to researchers and this reflexive account explores my reflections on the use of two such techniques. As part of a larger investigation, two pilot studies were undertaken as a means to examine the relative merits of open coding and template coding for examining transcripts. This article does not describe the research project per se but attempts to step back and offer a reflexive account of the development of data coding tools. Here I reflect upon and evaluate the two data coding techniques that were piloted, and discuss how using appropriate aspects of both led to the development of my final data coding approach. My exploration found there was no clear-cut ‘best’ option but that the data coding techniques needed to be reflexively-aligned to meet the specific needs of my project. This reflection suggests that, when coding qualitative data, researchers should be methodologically thoughtful when they attempt to apply any data coding technique; that they do not assume pre-established tools are aligned to their particular paradigm; and that they consider combining and refining established techniques as a means to define their own specific codes. DOI: 10.2458/azu_jmmss.v6i1.18772DOI: 10.2458/azu_jmmss.v6i1.18772

Constructing a two bands optical code-division multiple-access network of bipolar optical access codecs using Walsh-coded liquid crystal modulators

Science.gov (United States)

Yen, Chih-Ta; Huang, Jen-Fa; Chih, Ping-En

2014-08-01

We propose and experimentally demonstrated the two bands optical code-division multiple-access (OCDMA) network over bipolar Walsh-coded liquid-crystal modulators (LCMs) and driven by green light and red light lasers. Achieving system performance depends on the construction of a decoder that implements a true bipolar correlation using only unipolar signals and intensity detection for each band. We took advantage of the phase delay characteristics of LCMs to construct a prototype optical coder/decoder (codec). Matched and unmatched Walsh signature codes were evaluated to detect correlations among multiuser data in the access network. By using LCMs, a red and green laser light source was spectrally encoded and the summed light dots were complementary decoded. Favorable contrast on auto- and cross-correlations indicates that binary information symbols can be properly recovered using a balanced photodetector.

Wavelength-encoding/temporal-spreading optical code division multiple-access system with in-fiber chirped moiré gratings.

Science.gov (United States)

Chen, L R; Smith, P W; de Sterke, C M

1999-07-20

We propose an optical code division multiple-access (OCDMA) system that uses in-fiber chirped moiré gratings (CMG's) for encoding and decoding of broadband pulses. In reflection the wavelength-selective and dispersive nature of CMG's can be used to implement wavelength-encoding/temporal-spreading OCDMA. We give examples of codes designed around the constraints imposed by the encoding devices and present numerical simulations that demonstrate the proposed concept.

Simulation Performance of Multiple-Input Multiple-Output Systems Employing Single-Carrier Modulation and Orthogonal Frequency Division Multiplexing

National Research Council Canada - National Science Library

Saglam, Halil D

2004-01-01

...) systems utilizing Alamouti-based space-time block coding (STBC) technique. The MIMO communication systems using STBC technique employing both single-carrier modulation and orthogonal frequency division multiplexing (OFDM...

Novel secure and bandwidth efficient optical code division multiplexed system for future access networks

Science.gov (United States)

Singh, Simranjit

2016-12-01

In this paper, a spectrally coded optical code division multiple access (OCDMA) system using a hybrid modulation scheme has been investigated. The idea is to propose an effective approach for simultaneous improvement of the system capacity and security. Data formats, NRZ (non-return to zero), DQPSK (differential quadrature phase shift keying), and PoISk (polarisation shift keying) are used to get the orthogonal modulated signal. It is observed that the proposed hybrid modulation provides efficient utilisation of bandwidth, increases the data capacity and enhances the data confidentiality over existing OCDMA systems. Further, the proposed system performance is compared with the current state-of-the-art OCDMA schemes.

Generalized optical code construction for enhanced and Modified Double Weight like codes without mapping for SAC-OCDMA systems

Science.gov (United States)

Kumawat, Soma; Ravi Kumar, M.

2016-07-01

Double Weight (DW) code family is one of the coding schemes proposed for Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) systems. Modified Double Weight (MDW) code for even weights and Enhanced Double Weight (EDW) code for odd weights are two algorithms extending the use of DW code for SAC-OCDMA systems. The above mentioned codes use mapping technique to provide codes for higher number of users. A new generalized algorithm to construct EDW and MDW like codes without mapping for any weight greater than 2 is proposed. A single code construction algorithm gives same length increment, Bit Error Rate (BER) calculation and other properties for all weights greater than 2. Algorithm first constructs a generalized basic matrix which is repeated in a different way to produce the codes for all users (different from mapping). The generalized code is analysed for BER using balanced detection and direct detection techniques.

Division of Finance Homepage

Science.gov (United States)

Top Department of Administration logo Alaska Department of Administration Division of Finance Search Search the Division of Finance site DOF State of Alaska Finance Home Content Area Accounting Charge Cards You are here Administration / Finance Division of Finance Updates IRIS Expenditure Object Codes

Performance optimization of spectral amplitude coding OCDMA system using new enhanced multi diagonal code

Science.gov (United States)

Imtiaz, Waqas A.; Ilyas, M.; Khan, Yousaf

2016-11-01

This paper propose a new code to optimize the performance of spectral amplitude coding-optical code division multiple access (SAC-OCDMA) system. The unique two-matrix structure of the proposed enhanced multi diagonal (EMD) code and effective correlation properties, between intended and interfering subscribers, significantly elevates the performance of SAC-OCDMA system by negating multiple access interference (MAI) and associated phase induce intensity noise (PIIN). Performance of SAC-OCDMA system based on the proposed code is thoroughly analyzed for two detection techniques through analytic and simulation analysis by referring to bit error rate (BER), signal to noise ratio (SNR) and eye patterns at the receiving end. It is shown that EMD code while using SDD technique provides high transmission capacity, reduces the receiver complexity, and provides better performance as compared to complementary subtraction detection (CSD) technique. Furthermore, analysis shows that, for a minimum acceptable BER of 10-9 , the proposed system supports 64 subscribers at data rates of up to 2 Gbps for both up-down link transmission.

A design of a wavelength-hopping time-spreading incoherent optical code division multiple access system

International Nuclear Information System (INIS)

Glesk, I.; Baby, V.

2005-01-01

We present the architecture and code design for a highly scalable, 2.5 Gb/s per user optical code division multiple access (OCDMA) system. The system is scalable to 100 potential and more than 10 simultaneous users, each with a bit error rate (BER) of less than 10 -9 . The system architecture uses a fast wavelength-hopping, time-spreading codes. Unlike frequency and phase sensitive coherent OCDMA systems, this architecture utilizes standard on off keyed optical pulses allocated in the time and wavelength dimensions. This incoherent OCDMA approach is compatible with existing WDM optical networks and utilizes off the shelf components. We discuss the novel optical subsystem design for encoders and decoders that enable the realization of a highly scalable incoherent OCDMA system with rapid reconfigurability. A detailed analysis of the scalability of the two dimensional code is presented and select network deployment architectures for OCDMA are discussed (Authors)

46 CFR 54.01-2 - Adoption of division 1 of section VIII of the ASME Boiler and Pressure Vessel Code.

Science.gov (United States)

2010-10-01

... Boiler and Pressure Vessel Code. 54.01-2 Section 54.01-2 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... division 1 of section VIII of the ASME Boiler and Pressure Vessel Code. (a) Pressure vessels shall be designed, constructed, and inspected in accordance with section VIII of the ASME Boiler and Pressure Vessel...

Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system.

Science.gov (United States)

Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

2007-02-01

We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

Source coherence impairments in a direct detection direct sequence optical code-division multiple-access system

Science.gov (United States)

Fsaifes, Ihsan; Lepers, Catherine; Lourdiane, Mounia; Gallion, Philippe; Beugin, Vincent; Guignard, Philippe

2007-02-01

We demonstrate that direct sequence optical code- division multiple-access (DS-OCDMA) encoders and decoders using sampled fiber Bragg gratings (S-FBGs) behave as multipath interferometers. In that case, chip pulses of the prime sequence codes generated by spreading in time-coherent data pulses can result from multiple reflections in the interferometers that can superimpose within a chip time duration. We show that the autocorrelation function has to be considered as the sum of complex amplitudes of the combined chip as the laser source coherence time is much greater than the integration time of the photodetector. To reduce the sensitivity of the DS-OCDMA system to the coherence time of the laser source, we analyze the use of sparse and nonperiodic quadratic congruence and extended quadratic congruence codes.

Association between biliary complications and technique of hilar division (extrahepatic vs. intrahepatic in major liver resections

Directory of Open Access Journals (Sweden)

Gamaletsos Evangelos

2006-08-01

Full Text Available Abstract Background Division of major vascular and biliary structures during major hepatectomies can be carried out either extrahepatically at the porta hepatic or intrahepatically during the parenchymal transection. In this retrospective study we test the hypothesis that the intrahepatic technique is associated with less early biliary complications. Methods 150 patients who underwent major hepatectomies were retrospectively allocated into an intrahepatic group (n = 100 and an extrahepatic group (n = 50 based on the technique of hilar division. The two groups were operated by two different surgical teams, each one favoring one of the two approaches for hilar dissection. Operative data (warm ischemic time, operative time, blood loss, biliary complications, morbidity and mortality rates were analyzed. Results In extrahepatic patients, operative time was longer (245 ± 50 vs 214 ± 38 min, p Conclusion Intrahepatic hilar division is as safe as extrahepatic hilar division in terms of intraoperative blood requirements, morbidity and mortality. The extrahepatic technique is associated with more severe bile leaks and biliary injuries.

Performance of asynchronous fiber-optic code division multiple access system based on three-dimensional wavelength/time/space codes and its link analysis.

Science.gov (United States)

Singh, Jaswinder

2010-03-10

A novel family of three-dimensional (3-D) wavelength/time/space codes for asynchronous optical code-division-multiple-access (CDMA) systems with "zero" off-peak autocorrelation and "unity" cross correlation is reported. Antipodal signaling and differential detection is employed in the system. A maximum of [(W x T+1) x W] codes are generated for unity cross correlation, where W and T are the number of wavelengths and time chips used in the code and are prime. The conditions for violation of the cross-correlation constraint are discussed. The expressions for number of generated codes are determined for various code dimensions. It is found that the maximum number of codes are generated for S systems. The codes have a code-set-size to code-size ratio greater than W/S. For instance, with a code size of 2065 (59 x 7 x 5), a total of 12,213 users can be supported, and 130 simultaneous users at a bit-error rate (BER) of 10(-9). An arrayed-waveguide-grating-based reconfigurable encoder/decoder design for 2-D implementation for the 3-D codes is presented so that the need for multiple star couplers and fiber ribbons is eliminated. The hardware requirements of the coders used for various modulation/detection schemes are given. The effect of insertion loss in the coders is shown to be significantly reduced with loss compensation by using an amplifier after encoding. An optical CDMA system for four users is simulated and the results presented show the improvement in performance with the use of loss compensation.

Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation

Science.gov (United States)

Wang, C.-W.; Stark, W.

2005-01-01

This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.

Employing optical code division multiple access technology in the all fiber loop vibration sensor system

Science.gov (United States)

Tseng, Shin-Pin; Yen, Chih-Ta; Syu, Rong-Shun; Cheng, Hsu-Chih

2013-12-01

This study proposes a spectral amplitude coding-optical code division multiple access (SAC-OCDMA) framework to access the vibration frequency of a test object on the all fiber loop vibration sensor (AFLVS). Each user possesses an individual SAC, and fiber Bragg grating (FBG) encoders/decoders using multiple FBG arrays were adopted, providing excellent orthogonal properties in the frequency domain. The system also mitigates multiple access interference (MAI) among users. When an optical fiber is bent to a point exceeding the critical radius, the fiber loop sensor becomes sensitive to external physical parameters (e.g., temperature, strain, and vibration). The AFLVS involves placing a fiber loop with a specific radius on a designed vibration platform.

Gigabit Ethernet signal transmission using asynchronous optical code division multiple access.

Science.gov (United States)

Ma, Philip Y; Fok, Mable P; Shastri, Bhavin J; Wu, Ben; Prucnal, Paul R

2015-12-15

We propose and experimentally demonstrate a novel architecture for interfacing and transmitting a Gigabit Ethernet (GbE) signal using asynchronous incoherent optical code division multiple access (OCDMA). This is the first such asynchronous incoherent OCDMA system carrying GbE data being demonstrated to be working among multi-users where each user is operating with an independent clock/data rate and is granted random access to the network. Three major components, the GbE interface, the OCDMA transmitter, and the OCDMA receiver are discussed in detail. The performance of the system is studied and characterized through measuring eye diagrams, bit-error rate and packet loss rate in real-time file transfer. Our Letter also addresses the near-far problem and realizes asynchronous transmission and detection of signal.

Effect of beat noise on the performance of two-dimensional time-spreading/wavelength-hopping optical code-division multiple-access systems

Science.gov (United States)

Bazan, T.; Harle, D.; Andonovic, I.; Meenakshi, M.

2005-03-01

The effect of beat noise on optical code-division multiple-access (OCDMA) systems using a range of two-dimensional (2-D) time-spreading/wavelength-hopping (TW) code families is presented. A derivation of a general formula for the error probability of the system is given. The properties of the 2-D codes--namely, the structure, length, and cross-correlation characteristics--are found to have a great influence on system performance. Improved performance can be obtained by use of real-time dynamic thresholding.

Concealed holographic coding for security applications by using a moire technique

DEFF Research Database (Denmark)

Zhang, Xiangsu; Dalsgaard, Erik

1997-01-01

We present an optical coding technique that enhances the anticounterfeiting power of security holograms. The principles of the technique is based on the moire phenomenon. The code in the hologram has a phase pattern that is invisible and cannot be detected by optical equipment, so that imitation...... is extremely difficult. Holographic, photographic and embossing technique are used in fabricating coded holograms and decoders....

Electro-optical time gating based on Mach-Zehnder modulator for multiple access interference elimination in optical code-division multiple access networks

Science.gov (United States)

Chen, Yinfang; Wang, Rong; Fang, Tao; Pu, Tao; Xiang, Peng; Zheng, Jilin; Zhu, Huatao

2014-05-01

An electro-optical time gating technique, which is based on an electrical return-to-zero (RZ) pulse driven Mach-Zehnder modulator (MZM) for eliminating multiple access interference (MAI) in optical code-division multiple access (OCDMA) networks is proposed. This technique is successfully simulated in an eight-user two-dimensional wavelength-hopping time-spreading system, as well as in a three-user temporal phase encoding system. Results show that in both systems the MAI noise is efficiently removed and the average received power penalty improved. Both achieve error-free transmissions at a bit rate of 2.5 Gb/s. In addition, we also individually discuss effects of parameters in two systems, such as the extinction ratio of the MZM, the duty cycle of the driven RZ pulse, and the time misalignment between the driven pulse and the decoded autocorrelation peak, on the output bit error rate performance. Our work shows that employing a common MZM as a thresholder provides another probability and an interesting cost-effective choice for a smart size, low energy, and less complex thresholding technique for integrated detection in OCDMA networks.

Mitigation of Beat Noise in Time Wavelength Optical Code-Division Multiple-Access Systems

Science.gov (United States)

Bazan, Taher M.; Harle, David; Andonovic, Ivan

2006-11-01

This paper presents an analysis of two methods for enhancing the performance of two-dimensional time wavelength Optical code-division multiple-access systems by mitigating the effects of beat noise. The first methodology makes use of an optical hard limiter (OHL) in the receiver prior to the optical correlator; a general formula for the error probability as a function of crosstalk level for systems adopting OHLs is given, and the implications of the OHL's nonideal transfer characteristics are then examined. The second approach adopts pulse position modulation, and system performance is estimated and compared to that associated with on off keying.

Performance Evaluation of HARQ Technique with UMTS Turbo Code

Directory of Open Access Journals (Sweden)

S. S. Brkić

2011-11-01

Full Text Available The hybrid automatic repeat request technique (HARQ represents the error control principle which combines an error correcting code and automatic repeat request procedure (ARQ, within the same transmission system. In this paper, using Monte Carlo simulation process, the characteristics of HARQ technique are determined, for the case of the Universal Mobile Telecommunication System (UMTS turbo code.

Performance analysis of 2D asynchronous hard-limiting optical code-division multiple access system through atmospheric scattering channel

Science.gov (United States)

Zhao, Yaqin; Zhong, Xin; Wu, Di; Zhang, Ye; Ren, Guanghui; Wu, Zhilu

2013-09-01

Optical code-division multiple access (OCDMA) systems usually allocate orthogonal or quasi-orthogonal codes to the active users. When transmitting through atmospheric scattering channel, the coding pulses are broadened and the orthogonality of the codes is worsened. In truly asynchronous case, namely both the chips and the bits are asynchronous among each active user, the pulse broadening affects the system performance a lot. In this paper, we evaluate the performance of a 2D asynchronous hard-limiting wireless OCDMA system through atmospheric scattering channel. The probability density function of multiple access interference in truly asynchronous case is given. The bit error rate decreases as the ratio of the chip period to the root mean square delay spread increases and the channel limits the bit rate to different levels when the chip period varies.

Divisible ℤ-modules

Directory of Open Access Journals (Sweden)

Futa Yuichi

2016-03-01

Full Text Available In this article, we formalize the definition of divisible ℤ-module and its properties in the Mizar system [3]. We formally prove that any non-trivial divisible ℤ-modules are not finitely-generated.We introduce a divisible ℤ-module, equivalent to a vector space of a torsion-free ℤ-module with a coefficient ring ℚ. ℤ-modules are important for lattice problems, LLL (Lenstra, Lenstra and Lovász base reduction algorithm [15], cryptographic systems with lattices [16] and coding theory [8].

Performance analysis of WS-EWC coded optical CDMA networks with/without LDPC codes

Science.gov (United States)

Huang, Chun-Ming; Huang, Jen-Fa; Yang, Chao-Chin

2010-10-01

One extended Welch-Costas (EWC) code family for the wavelength-division-multiplexing/spectral-amplitude coding (WDM/SAC; WS) optical code-division multiple-access (OCDMA) networks is proposed. This system has a superior performance as compared to the previous modified quadratic congruence (MQC) coded OCDMA networks. However, since the performance of such a network is unsatisfactory when the data bit rate is higher, one class of quasi-cyclic low-density parity-check (QC-LDPC) code is adopted to improve that. Simulation results show that the performance of the high-speed WS-EWC coded OCDMA network can be greatly improved by using the LDPC codes.

Multiuser Random Coding Techniques for Mismatched Decoding

OpenAIRE

Scarlett, Jonathan; Martinez, Alfonso; Guillén i Fàbregas, Albert

2016-01-01

This paper studies multiuser random coding techniques for channel coding with a given (possibly suboptimal) decoding rule. For the mismatched discrete memoryless multiple-access channel, an error exponent is obtained that is tight with respect to the ensemble average, and positive within the interior of Lapidoth's achievable rate region. This exponent proves the ensemble tightness of the exponent of Liu and Hughes in the case of maximum-likelihood decoding. An equivalent dual form of Lapidoth...

DIVISIONS AND SEGREGATIONS OF THE PATRIMONY

Directory of Open Access Journals (Sweden)

CRISTIAN GHEORGHE

2012-05-01

Full Text Available For a long time, dispute resolution and alternative techniques like mediation have been dealing with a classic conception: every part involved in dispute resolution was carrying exactly one patrimony. Irrespective of physical or moral person the rule was the same: one person, one patrimony. Alternative dispute resolution, like mediation, dealt with persons in order to reach a mutual agreement affecting their unique patrimony. The rule is already history. Still remain the first premise: every person has a patrimony. But under present Civil code the provision is stopping here. As a result, the uniqueness of the patrimony vanished from new law. Dealing with different patrimonies a dispute solver should be able to understand the new notion and to assist the parties to finals agreements according to the rules of the divisions of the patrimony. First at all we should observe that any division of the patrimony of a person have to have a legal basis. The “liberalisation” of the patrimony is not so advanced in order to accept any voluntary division of the patrimony of the person. Second, the prominent creation in this field are represented by fiducia (a kind of Anglo-Saxon trust concept and assigned patrimony. Fiducia is new for our legal system only, following in fact the Quebec civil code regulation. The assigned patrimony was already been present in our legislation. The Ordinance no 44/2008 was dealing with this concept in commercial field.

76 FR 36231 - American Society of Mechanical Engineers (ASME) Codes and New and Revised ASME Code Cases

Science.gov (United States)

2011-06-21

...The NRC is amending its regulations to incorporate by reference the 2005 Addenda (July 1, 2005) and 2006 Addenda (July 1, 2006) to the 2004 ASME Boiler and Pressure Vessel Code, Section III, Division 1; 2007 ASME Boiler and Pressure Vessel Code, Section III, Division 1, 2007 Edition (July 1, 2007), with 2008a Addenda (July 1, 2008); 2005 Addenda (July 1, 2005) and 2006 Addenda (July 1, 2006) to the 2004 ASME Boiler and Pressure Vessel Code, Section XI, Division 1; 2007 ASME Boiler and Pressure Vessel Code, Section XI, Division 1, 2007 Edition (July 1, 2007), with 2008a Addenda (July 1, 2008); and 2005 Addenda, ASME OMa Code-2005 (approved July 8, 2005) and 2006 Addenda, ASME OMb Code-2006 (approved July 6, 2006) to the 2004 ASME Code for Operation and Maintenance of Nuclear Power Plants (OM Code). The NRC is also incorporating by reference (with conditions on their use) ASME Boiler and Pressure Vessel Code Case N-722-1, ``Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated with Alloy 600/82/182 Materials, Section XI, Division 1,'' Supplement 8, ASME approval date: January 26, 2009, and ASME Boiler and Pressure Vessel Code Case N-770-1, ``Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated With UNS N06082 or UNS W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities, Section XI, Division 1,'' ASME approval date: December 25, 2009.

A precise form of divisive suppression supports population coding in the primary visual cortex.

Science.gov (United States)

MacEvoy, Sean P; Tucker, Thomas R; Fitzpatrick, David

2009-05-01

The responses of neurons in the primary visual cortex (V1) to an optimally oriented grating are suppressed when a non-optimal grating is superimposed. Although cross-orientation suppression is thought to reflect mechanisms that maintain a distributed code for orientation, the effect of superimposed gratings on V1 population responses is unknown. Using intrinsic signal optical imaging, we found that patterns of tree shrew V1 activity evoked by superimposed equal-contrast gratings were predicted by the averages of patterns evoked by individual component gratings. This prediction held across contrasts, for summed sinusoidal gratings or nonsumming square-wave gratings, and was evident in single-unit extracellular recordings. Intracellular recordings revealed consistent levels of suppression throughout the time course of subthreshold responses. These results indicate that divisive suppression powerfully governs population responses to multiple orientations. Moreover, the specific form of suppression that we observed appears to support independent population codes for stimulus orientation and strength and calls for a reassessment of mechanisms that underlie cross-orientation suppression.

PEAK-TO-AVERAGE POWER RATIO REDUCTION USING CODING AND HYBRID TECHNIQUES FOR OFDM SYSTEM

OpenAIRE

Bahubali K. Shiragapur; Uday Wali

2016-01-01

In this article, the research work investigated is based on an error correction coding techniques are used to reduce the undesirable Peak-to-Average Power Ratio (PAPR) quantity. The Golay Code (24, 12), Reed-Muller code (16, 11), Hamming code (7, 4) and Hybrid technique (Combination of Signal Scrambling and Signal Distortion) proposed by us are used as proposed coding techniques, the simulation results shows that performance of Hybrid technique, reduces PAPR significantly as compared to Conve...

A novel technique to increase the capacity of code division multiple ...

African Journals Online (AJOL)

linear parallel interference cancellation (WLPIC) technique for N = 64 at a Bit Error Rate (BER) of 10-3 and 75% overloading at a BER of 10-2. The three-stage WLPIC scheme clearly outperforms matched filter detector, Conventional LPIC and the twostage WLPIC on Additive White Gaussian Noise (AWGN) channel.

Performance of an Error Control System with Turbo Codes in Powerline Communications

Directory of Open Access Journals (Sweden)

Balbuena-Campuzano Carlos Alberto

2014-07-01

Full Text Available This paper reports the performance of turbo codes as an error control technique in PLC (Powerline Communications data transmissions. For this system, computer simulations are used for modeling data networks based on the model classified in technical literature as indoor, and uses OFDM (Orthogonal Frequency Division Multiplexing as a modulation technique. Taking into account the channel, modulation and turbo codes, we propose a methodology to minimize the bit error rate (BER, as a function of the average received signal noise ratio (SNR.

On Analyzing LDPC Codes over Multiantenna MC-CDMA System

Directory of Open Access Journals (Sweden)

S. Suresh Kumar

2014-01-01

Full Text Available Multiantenna multicarrier code-division multiple access (MC-CDMA technique has been attracting much attention for designing future broadband wireless systems. In addition, low-density parity-check (LDPC code, a promising near-optimal error correction code, is also being widely considered in next generation communication systems. In this paper, we propose a simple method to construct a regular quasicyclic low-density parity-check (QC-LDPC code to improve the transmission performance over the precoded MC-CDMA system with limited feedback. Simulation results show that the coding gain of the proposed QC-LDPC codes is larger than that of the Reed-Solomon codes, and the performance of the multiantenna MC-CDMA system can be greatly improved by these QC-LDPC codes when the data rate is high.

Optical network security using unipolar Walsh code

Science.gov (United States)

Sikder, Somali; Sarkar, Madhumita; Ghosh, Shila

2018-04-01

Optical code-division multiple-access (OCDMA) is considered as a good technique to provide optical layer security. Many research works have been published to enhance optical network security by using optical signal processing. The paper, demonstrates the design of the AWG (arrayed waveguide grating) router-based optical network for spectral-amplitude-coding (SAC) OCDMA networks with Walsh Code to design a reconfigurable network codec by changing signature codes to against eavesdropping. In this paper we proposed a code reconfiguration scheme to improve the network access confidentiality changing the signature codes by cyclic rotations, for OCDMA system. Each of the OCDMA network users is assigned a unique signature code to transmit the information and at the receiving end each receiver correlates its own signature pattern a(n) with the receiving pattern s(n). The signal arriving at proper destination leads to s(n)=a(n).

PEAK-TO-AVERAGE POWER RATIO REDUCTION USING CODING AND HYBRID TECHNIQUES FOR OFDM SYSTEM

Directory of Open Access Journals (Sweden)

Bahubali K. Shiragapur

2016-03-01

Full Text Available In this article, the research work investigated is based on an error correction coding techniques are used to reduce the undesirable Peak-to-Average Power Ratio (PAPR quantity. The Golay Code (24, 12, Reed-Muller code (16, 11, Hamming code (7, 4 and Hybrid technique (Combination of Signal Scrambling and Signal Distortion proposed by us are used as proposed coding techniques, the simulation results shows that performance of Hybrid technique, reduces PAPR significantly as compared to Conventional and Modified Selective mapping techniques. The simulation results are validated through statistical properties, for proposed technique’s autocorrelation value is maximum shows reduction in PAPR. The symbol preference is the key idea to reduce PAPR based on Hamming distance. The simulation results are discussed in detail, in this article.

Environmental Sciences Division. Annual progress report for period ending September 30, 1975

Energy Technology Data Exchange (ETDEWEB)

1976-08-01

The energy crisis and creation of ERDA were dominant factors affecting the activities of the Environmental Sciences Division during the past year. Efforts primarily centered on coal conversion effluents, aquatic effects from power plants, terrestrial modeling of both radioactive and nonradioactive waste transport, mineral cycling, forest management, and information handling codes and techniques. A bibliography of publications, presentation, these, and other professional activities is included. (PCS)

Optical orthogonal code-division multiple-access system - Part 2: Multibits/sequence-period OOCDMA

Science.gov (United States)

Kwon, Hyuck M.

1994-08-01

In a recently proposed optical orthogonal code division multiple-access (OOCDMA) system, one bit of user's data is transmitted per sequence-period, and a threshold is employed for the final bit decision. In this paper, a system that can transmit multibits per sequence-period is introduced, and avalanche photodiode (APD) noise, thermal noise, and interference, are included. This system, derived by exploiting orthogonal properties of the OOCDMA code sequence and using a maximum search (instead of a threshold) in the final decision, is log(sub 2) F times higher in throughput, where F is sequence-period. For example, four orders of magnitude are better in bit error probability at - 56 dBW received laser power, with F = 1000 chips, 10 'marks' in a sequence, and 10 users of 30 Mb/s data rate for one-bit/sequence-period and 270 Mb/s data rate for multibits/sequence-period system. Furthermore, an exact analysis is performed for the log(sub 2)F bits/sequence-period system with a hard-limiter placed before the receiver, and its performance is compared to the performance without hard-limiter, for the chip-synchronous case. The improvement from using a hard-limiter is significant in the log(sub 2)F bits/sequence-period OCCDMA system.

75 FR 24323 - American Society of Mechanical Engineers (ASME) Codes and New and Revised ASME Code Cases

Science.gov (United States)

2010-05-04

...The NRC proposes to amend its regulations to incorporate by reference the 2005 Addenda through 2008 Addenda of Section III, Division 1, and the 2005 Addenda through 2008 Addenda of Section XI, Division 1, of the ASME Boiler and Pressure Vessel Code (ASME B&PV Code); and the 2005 Addenda and 2006 Addenda of the ASME Code for Operation and Maintenance of Nuclear Power Plants (ASME OM Code). The NRC also proposes to incorporate by reference ASME Code Case N-722-1, ``Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated With Alloy 600/82/182 Materials Section XI, Division 1,'' and Code Case N-770, ``Alternative Examination Requirements and Acceptance Standards for Class 1 PWR [Pressurized- Water Reactor] Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNS W86182 Weld Filler Material with or without Application of Listed Mitigation Activities.''

Optics code development at Los Alamos

International Nuclear Information System (INIS)

Mottershead, C.T.; Lysenko, W.P.

1988-01-01

This paper is an overview of part of the beam optics code development effort in the Accelerator Technology Division at Los Alamos National Laboratory. The aim of this effort is to improve our capability to design advanced beam optics systems. The work reported is being carried out by a collaboration of permanent staff members, visiting consultants, and student research assistants. The main components of the effort are: building a new framework of common supporting utilities and software tools to facilitate further development; research and development on basic computational techniques in classical mechanics and electrodynamics; and evaluation and comparison of existing beam optics codes, and support for their continuing development. 17 refs

Optics code development at Los Alamos

International Nuclear Information System (INIS)

Mottershead, C.T.; Lysenko, W.P.

1988-01-01

This paper is an overview of part of the beam optics code development effort in the Accelerator Technology Division at Los Alamos National Laboratory. The aim of this effort is to improve our capability to design advanced beam optics systems. The work reported is being carried out by a collaboration of permanent staff members, visiting consultants, and student research assistants. The main components of the effort are building a new framework of common supporting utilities and software tools to facilitate further development. research and development on basic computational techniques in classical mechanics and electrodynamics, and evaluation and comparison of existing beam optics codes, and support for their continuing development

Beat Noise Cancellation in 2-D Optical Code-Division Multiple-Access Systems Using Optical Hard-Limiter Array

Science.gov (United States)

Dang, Ngoc T.; Pham, Anh T.; Cheng, Zixue

We analyze the beat noise cancellation in two-dimensional optical code-division multiple-access (2-D OCDMA) systems using an optical hard-limiter (OHL) array. The Gaussian shape of optical pulse is assumed and the impact of pulse propagation is considered. We also take into account the receiver noise and multiple access interference (MAI) in the analysis. The numerical results show that, when OHL array is employed, the system performance is greatly improved compared with the cases without OHL array. Also, parameters needed for practical system design are comprehensively analyzed.

Zero-Forcing Pre-coding for MIMO WiMAX Transceivers

DEFF Research Database (Denmark)

Cattoni, Andrea Fabio; Le Moullec, Yannick; Sacchi, Claudio

2013-01-01

with the benefits of space division multiple access. In MU-MIMO systems, the base stations transmit signals to two or more users over the same channel, for this reason every user can experience inter-user interference. This paper provides a capacity analysis of an online, interference-based pre-coding algorithm...... of the analyzed technique in a possible FPGA-based software defined radio....

Fresh Prime Codes Evaluation for Synchronous PPM and OPPM Signaling for Optical CDMA Networks

Science.gov (United States)

Karbassian, M. Massoud; Ghafouri-Shiraz, H.

2007-06-01

In this paper, we have proposed a novel prime spreading sequence family hereby referred to as “Double-Padded Modified Prime Code (DPMPC)” for direct-detection synchronous optical code-division multiple-access (OCDMA) networks. The new code is applied to both pulse-position and overlapping pulse-position modulation CDMA networks, and their performances were evaluated and compared with existing prime codes family. In addition, we have analyzed the system throughput and also introduced a new interference cancellation technique which significantly improves the bit error probability of OCDMA networks.

Fast decoding techniques for extended single-and-double-error-correcting Reed Solomon codes

Science.gov (United States)

Costello, D. J., Jr.; Deng, H.; Lin, S.

1984-01-01

A problem in designing semiconductor memories is to provide some measure of error control without requiring excessive coding overhead or decoding time. For example, some 256K-bit dynamic random access memories are organized as 32K x 8 bit-bytes. Byte-oriented codes such as Reed Solomon (RS) codes provide efficient low overhead error control for such memories. However, the standard iterative algorithm for decoding RS codes is too slow for these applications. Some special high speed decoding techniques for extended single and double error correcting RS codes. These techniques are designed to find the error locations and the error values directly from the syndrome without having to form the error locator polynomial and solve for its roots.

Novel Equalization Techniques for Space Division Multiplexing Based on Stokes Space Update Rule

Directory of Open Access Journals (Sweden)

Francisco Javier Vaquero Caballero

2017-02-01

Full Text Available Space division multiplexing (SDM is a promising technology that aims to overcome the capacity crunch of optical communications. In this paper, we introduce the multiple-input multiple-output (MIMO Stokes Space Algorithm (SSA implemented in frequency domain, a novel equalization technique for space division multiplexing (SDM. Although different papers have been published about the SSA and its MIMO implementation, we provide for the first time an analysis of the of the convergence speed and frequency offset of the SSA compared to the least mean square (LMS. SSA algorithm can deal with higher frequency offsets and linewidths than LMS, being suitable for optical communications with higher phase noise. SSA does not need pre-compensation of frequency offset, which can be compensated after equalization without penalties. On the other hand, due to reduced convergence speed, SSA requires longer training sequences than LMS.

New Technique for Improving Performance of LDPC Codes in the Presence of Trapping Sets

Directory of Open Access Journals (Sweden)

Mohamed Adnan Landolsi

2008-06-01

Full Text Available Trapping sets are considered the primary factor for degrading the performance of low-density parity-check (LDPC codes in the error-floor region. The effect of trapping sets on the performance of an LDPC code becomes worse as the code size decreases. One approach to tackle this problem is to minimize trapping sets during LDPC code design. However, while trapping sets can be reduced, their complete elimination is infeasible due to the presence of cycles in the underlying LDPC code bipartite graph. In this work, we introduce a new technique based on trapping sets neutralization to minimize the negative effect of trapping sets under belief propagation (BP decoding. Simulation results for random, progressive edge growth (PEG and MacKay LDPC codes demonstrate the effectiveness of the proposed technique. The hardware cost of the proposed technique is also shown to be minimal.

Spectral Amplitude Coding (SAC)-OCDMA Network with 8DPSK

Science.gov (United States)

Aldhaibani, A. O.; Aljunid, S. A.; Fadhil, Hilal A.; Anuar, M. S.

2013-09-01

Optical code division multiple access (OCDMA) technique is required to meet the increased demand for high speed, large capacity communications in optical networks. In this paper, the transmission performance of a spectral amplitude coding (SAC)-OCDMA network is investigated when a conventional single-mode fiber (SMF) is used as the transmission link using 8DPSK modulation. The DW has a fixed weight of two. Simulation results reveal that the transmission distance is limited mainly by the fiber dispersion when high coding chip rate is used. For a two-user SAC-OCDMA network operating with 2 Gbit/s data rate and two wavelengths for each user, the maximum allowable transmission distance is about 15 km.

H-Division quarterly report, April--June 1976

International Nuclear Information System (INIS)

1976-01-01

The purview of H-Division is the mechanics of fluids and solid bodies. Concise status reports of the projects undertaken by the various groups in the division are given. Representative topics studied include equations of state of various materials, fracture mechanics, penetration of armor by projectiles, turbulence generation, and the development of dynamics computer codes. 31 figures, 2 tables

SPECTRAL AMPLITUDE CODING OCDMA SYSTEMS USING ENHANCED DOUBLE WEIGHT CODE

Directory of Open Access Journals (Sweden)

F.N. HASOON

2006-12-01

Full Text Available A new code structure for spectral amplitude coding optical code division multiple access systems based on double weight (DW code families is proposed. The DW has a fixed weight of two. Enhanced double-weight (EDW code is another variation of a DW code family that can has a variable weight greater than one. The EDW code possesses ideal cross-correlation properties and exists for every natural number n. A much better performance can be provided by using the EDW code compared to the existing code such as Hadamard and Modified Frequency-Hopping (MFH codes. It has been observed that theoretical analysis and simulation for EDW is much better performance compared to Hadamard and Modified Frequency-Hopping (MFH codes.

New coding technique for computer generated holograms.

Science.gov (United States)

Haskell, R. E.; Culver, B. C.

1972-01-01

A coding technique is developed for recording computer generated holograms on a computer controlled CRT in which each resolution cell contains two beam spots of equal size and equal intensity. This provides a binary hologram in which only the position of the two dots is varied from cell to cell. The amplitude associated with each resolution cell is controlled by selectively diffracting unwanted light into a higher diffraction order. The recording of the holograms is fast and simple.

The Technique of Binary Code Decompilation and Its Application in Information Security Sphere

Directory of Open Access Journals (Sweden)

M. O. Shudrak

2012-12-01

Full Text Available The authors describes a new technique of binary code decompilation and its application possibility in information security such as software protection against reverse engineering and code obfuscation analyze in malware.

Short-range remote spectral sensor using mid-infrared semiconductor lasers with orthogonal code-division multiplexing approach

Science.gov (United States)

Morbi, Zulfikar; Ho, D. B.; Ren, H.-W.; Le, Han Q.; Pei, Shin Shem

2002-09-01

Demonstration of short-range multispectral remote sensing, using 3 to 4-micrometers mid- infrared Sb semiconductor lasers based on code-division multiplexing (CDM) architecture, is described. The system is built on a principle similar to intensity- modulated/direct-detection optical-CDMA for communications, but adapted for sensing with synchronous, orthogonal codes to distinguish different wavelength channels with zero interchannel correlation. The concept is scalable for any number of channels, and experiments with a two-wavelength system are conducted. The CDM-signal processing yielded a white-Gaussian-like system noise that is found to be near the theoretical level limited by the detector fundamental intrinsic noise. With sub-mW transmitter average power, the system was able to detect an open-air acetylene gas leak of 10-2 STP ft3/hr from 10-m away with time-varying, random, noncooperative backscatters. A similar experiment detected and positively distinguished hydrocarbon oil contaminants on water from bio-organic oils and detergents. Projection for more advanced systems suggests a multi-kilometer-range capability for watt-level transmitters, and hundreds of wavelength channels can also be accommodated for active hyperspectral remote sensing application.

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1978-10-01

Research activities in the Division of Reactor Engineering in fiscal 1977 are described. Works of the Division are development of multi-purpose Very High Temperature Gas Cooled Reactor, fusion reactor engineering, and development of Liquid Metal Fast Breeder Reactor for Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology, and Committee on Reactor Physics. (Author)

Code of Ethics

Science.gov (United States)

Division for Early Childhood, Council for Exceptional Children, 2009

2009-01-01

The Code of Ethics of the Division for Early Childhood (DEC) of the Council for Exceptional Children is a public statement of principles and practice guidelines supported by the mission of DEC. The foundation of this Code is based on sound ethical reasoning related to professional practice with young children with disabilities and their families…

BLINDAGE: A neutron and gamma-ray transport code for shieldings with the removal-diffusion technique coupled with the point-kernel technique

International Nuclear Information System (INIS)

Fanaro, L.C.C.B.

1984-01-01

It was developed the BLINDAGE computer code for the radiation transport (neutrons and gammas) calculation. The code uses the removal - diffusion method for neutron transport and point-kernel technique with buil-up factors for gamma-rays. The results obtained through BLINDAGE code are compared with those obtained with the ANISN and SABINE computer codes. (Author) [pt

Performance analysis of spectral-phase-encoded optical code-division multiple-access system regarding the incorrectly decoded signal as a nonstationary random process

Science.gov (United States)

Yan, Meng; Yao, Minyu; Zhang, Hongming

2005-11-01

The performance of a spectral-phase-encoded (SPE) optical code-division multiple-access (OCDMA) system is analyzed. Regarding the incorrectly decoded signal (IDS) as a nonstationary random process, we derive a novel probability distribution for it. The probability distribution of the IDS is considered a chi-squared distribution with degrees of freedom r=1, which is more reasonable and accurate than in previous work. The bit error rate (BER) of an SPE OCDMA system under multiple-access interference is evaluated. Numerical results show that the system can sustain very low BER even when there are multiple simultaneous users, and as the code length becomes longer or the initial pulse becomes shorter, the system performs better.

A new two-code keying scheme for SAC-OCDMA systems enabling bipolar encoding

Science.gov (United States)

Al-Khafaji, Hamza M. R.; Ngah, Razali; Aljunid, S. A.; Rahman, T. A.

2015-03-01

In this paper, we propose a new two-code keying scheme for enabling bipolar encoding in a high-rate spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) system. The mathematical formulations are derived for the signal-to-noise ratio and bit-error rate (BER) of SAC-OCDMA system based on the suggested scheme using multi-diagonal (MD) code. Performance analyses are assessed considering the effects of phase-induced intensity noise, as well as shot and thermal noises in photodetectors. The numerical results demonstrated that the proposed scheme exhibits an enhanced BER performance compared to the existing unipolar encoding with direct detection technique. Furthermore, the performance improvement afforded by this scheme is verified using simulation experiments.

Percutaneous tenotomy: development of a novel, percutaneous, ultrasound-guided needle-cutting technique for division of tendons and other connective tissue structures

International Nuclear Information System (INIS)

Hopkins, James; Sampson, Matthew

2014-01-01

A variety of surgical procedures derive therapeutic benefit from the division of retinacular, ligamentous or tendinous structures. Examples include carpal tunnel release for median nerve impingement, annular pulley release for trigger finger and tendon division for spastic muscular contractures. Here, using an animal cadaveric model, we describe the first steps in determining the feasibility of a novel, percutaneous, ultrasound-guided needle-cutting technique to achieve the same ends. The technique we describe involves the creation of an effective needle tenotomy device via a simple modification to an 18G coaxial, beveled needle. The technique holds promise for the development of a minimally invasive alternative approach that utilises readily available technology and equipment with minimisation of morbidity and cost associated with open procedures.

Cardinality enhancement utilizing Sequential Algorithm (SeQ code in OCDMA system

Directory of Open Access Journals (Sweden)

Fazlina C. A. S.

2017-01-01

Full Text Available Optical Code Division Multiple Access (OCDMA has been important with increasing demand for high capacity and speed for communication in optical networks because of OCDMA technique high efficiency that can be achieved, hence fibre bandwidth is fully used. In this paper we will focus on Sequential Algorithm (SeQ code with AND detection technique using Optisystem design tool. The result revealed SeQ code capable to eliminate Multiple Access Interference (MAI and improve Bit Error Rate (BER, Phase Induced Intensity Noise (PIIN and orthogonally between users in the system. From the results, SeQ shows good performance of BER and capable to accommodate 190 numbers of simultaneous users contrast with existing code. Thus, SeQ code have enhanced the system about 36% and 111% of FCC and DCS code. In addition, SeQ have good BER performance 10-25 at 155 Mbps in comparison with 622 Mbps, 1 Gbps and 2 Gbps bit rate. From the plot graph, 155 Mbps bit rate is suitable enough speed for FTTH and LAN networks. Resolution can be made based on the superior performance of SeQ code. Thus, these codes will give an opportunity in OCDMA system for better quality of service in an optical access network for future generation's usage

Cardinality enhancement utilizing Sequential Algorithm (SeQ) code in OCDMA system

Science.gov (United States)

Fazlina, C. A. S.; Rashidi, C. B. M.; Rahman, A. K.; Aljunid, S. A.

2017-11-01

Optical Code Division Multiple Access (OCDMA) has been important with increasing demand for high capacity and speed for communication in optical networks because of OCDMA technique high efficiency that can be achieved, hence fibre bandwidth is fully used. In this paper we will focus on Sequential Algorithm (SeQ) code with AND detection technique using Optisystem design tool. The result revealed SeQ code capable to eliminate Multiple Access Interference (MAI) and improve Bit Error Rate (BER), Phase Induced Intensity Noise (PIIN) and orthogonally between users in the system. From the results, SeQ shows good performance of BER and capable to accommodate 190 numbers of simultaneous users contrast with existing code. Thus, SeQ code have enhanced the system about 36% and 111% of FCC and DCS code. In addition, SeQ have good BER performance 10-25 at 155 Mbps in comparison with 622 Mbps, 1 Gbps and 2 Gbps bit rate. From the plot graph, 155 Mbps bit rate is suitable enough speed for FTTH and LAN networks. Resolution can be made based on the superior performance of SeQ code. Thus, these codes will give an opportunity in OCDMA system for better quality of service in an optical access network for future generation's usage

Techniques and Architectures for Hazard-Free Semi-Parallel Decoding of LDPC Codes

Directory of Open Access Journals (Sweden)

Rovini Massimo

2009-01-01

Full Text Available The layered decoding algorithm has recently been proposed as an efficient means for the decoding of low-density parity-check (LDPC codes, thanks to the remarkable improvement in the convergence speed (2x of the decoding process. However, pipelined semi-parallel decoders suffer from violations or "hazards" between consecutive updates, which not only violate the layered principle but also enforce the loops in the code, thus spoiling the error correction performance. This paper describes three different techniques to properly reschedule the decoding updates, based on the careful insertion of "idle" cycles, to prevent the hazards of the pipeline mechanism. Also, different semi-parallel architectures of a layered LDPC decoder suitable for use with such techniques are analyzed. Then, taking the LDPC codes for the wireless local area network (IEEE 802.11n as a case study, a detailed analysis of the performance attained with the proposed techniques and architectures is reported, and results of the logic synthesis on a 65 nm low-power CMOS technology are shown.

Implementation of Multiple Access Techniques Applicable for Maritime Satellite Communications

Directory of Open Access Journals (Sweden)

Stojce Dimov Ilcev

2013-12-01

Full Text Available In this paper are introduced fundamentals, characteristics, advantages and disadvantages of Multiple Access (MA employed as transmission techniques in the Maritime Mobile Satellite Communications (MMSC between ships and Coast Earth Station (CES via Geostationary Earth Orbit (GEO or Not-GEO satellite constellations. In fixed satellite communication, as a rule, especially in MMSC many users are active at the same time. The problem of simultaneous communications between many single or multipoint mobile satellite users can be solved by using MA technique, such as Frequency Division Multiple Access (FDMA, Time Division Multiple Access (TDMA, Code Division Multiple Access (CDMA, Space Division Multiple Access (SDMA and Random (Packet Division Multiple Access (RDMA. Since the resources of the systems such as the transmitting power and the bandwidth are limited, it is advisable to use the channels with complete charge and to create a different MA to the channel. This generates a problem of summation and separation of signals in the transmission and reception parts, respectively. Deciding this problem consists in the development of orthogonal channels of transmission in order to divide signals from various users unambiguously on the reception part.

Performance analysis for a chaos-based code-division multiple access system in wide-band channel

Directory of Open Access Journals (Sweden)

Ciprian Doru Giurcăneanu

2015-08-01

Full Text Available Code-division multiple access technology is widely used in telecommunications and its performance has been extensively investigated in the past. Theoretical results for the case of wide-band transmission channel were not available until recently. The novel formulae which have been published in 2014 can have an important impact on the future of wireless multiuser communications, but limitations come from the Gaussian approximations used in their derivation. In this Letter, the authors obtain more accurate expressions of the bit error rate (BER for the case when the model of the wide-band channel is two-ray, with Rayleigh fading. In the authors’ approach, the spreading sequences are assumed to be generated by logistic map given by Chebyshev polynomial function of order two. Their theoretical and experimental results show clearly that the previous results on BER, which rely on the crude Gaussian approximation, are over-pessimistic.

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

Hirota, Jitsuya; Asaoka, Takumi; Suzuki, Tomoo; Mitani, Hiroshi; Akino, Fujiyoshi

1977-09-01

Research activities in the Division of Reactor Engineering in fiscal 1976 are described. Works of the division concern mainly the development of multi-purpose Very High Temperature Gas Cooled Reactor, fusion reactor engineering, and the development of Liquid Metal Fast Breeder Reactor in Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology, and activities of the Committee on Reactor Physics. (auth.)

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1976-09-01

Research activities conducted in Reactor Engineering Division in fiscal 1975 are summarized in this report. Works in the division are closely related to the development of multi-purpose High-temperature Gas Cooled Reactor, the development of Liquid Metal Fast Breeder Reactor by Power Reactor and Nuclear Fuel Development Corporation, and engineering research of thermonuclear fusion reactor. Many achievements are described concerning nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology and activities of the Committee on Reactor Physics. (auth.)

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1975-11-01

Research activities in fiscal 1974 in Reactor Engineering Division of eight laboratories and computing center are described. Works in the division are closely related with the development of a multi-purpose High-temperature Gas Cooled Reactor, the development of a Liquid Metal Fast Breeder Reactor in Power Reactor and Nuclear Fuel Development Corporation, and engineering of thermonuclear fusion reactors. They cover nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology and aspects of the computing center. (auth.)

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

Matsuura, Shojiro; Nakahara, Yasuaki; Takano, Hideki

1982-09-01

Research and development activities in the Division of Reactor Engineering in fiscal 1981 are described. The work of the Division is closely related to development of multipurpose Very High Temperature Gas Cooled Reactor and fusion reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and fusion reactor technology, and activities of the Committee on Reactor Physics. (author)

Convolutional coding techniques for data protection

Science.gov (United States)

Massey, J. L.

1975-01-01

Results of research on the use of convolutional codes in data communications are presented. Convolutional coding fundamentals are discussed along with modulation and coding interaction. Concatenated coding systems and data compression with convolutional codes are described.

Chip-interleaved optical code division multiple access relying on a photon-counting iterative successive interference canceller for free-space optical channels.

Science.gov (United States)

Zhou, Xiaolin; Zheng, Xiaowei; Zhang, Rong; Hanzo, Lajos

2013-07-01

In this paper, we design a novel Poisson photon-counting based iterative successive interference cancellation (SIC) scheme for transmission over free-space optical (FSO) channels in the presence of both multiple access interference (MAI) as well as Gamma-Gamma atmospheric turbulence fading, shot-noise and background light. Our simulation results demonstrate that the proposed scheme exhibits a strong MAI suppression capability. Importantly, an order of magnitude of BER improvements may be achieved compared to the conventional chip-level optical code-division multiple-access (OCDMA) photon-counting detector.

Low Power LDPC Code Decoder Architecture Based on Intermediate Message Compression Technique

Science.gov (United States)

Shimizu, Kazunori; Togawa, Nozomu; Ikenaga, Takeshi; Goto, Satoshi

Reducing the power dissipation for LDPC code decoder is a major challenging task to apply it to the practical digital communication systems. In this paper, we propose a low power LDPC code decoder architecture based on an intermediate message-compression technique which features as follows: (i) An intermediate message compression technique enables the decoder to reduce the required memory capacity and write power dissipation. (ii) A clock gated shift register based intermediate message memory architecture enables the decoder to decompress the compressed messages in a single clock cycle while reducing the read power dissipation. The combination of the above two techniques enables the decoder to reduce the power dissipation while keeping the decoding throughput. The simulation results show that the proposed architecture improves the power efficiency up to 52% and 18% compared to that of the decoder based on the overlapped schedule and the rapid convergence schedule without the proposed techniques respectively.

Separate Turbo Code and Single Turbo Code Adaptive OFDM Transmissions

Directory of Open Access Journals (Sweden)

Burr Alister

2009-01-01

Full Text Available Abstract This paper discusses the application of adaptive modulation and adaptive rate turbo coding to orthogonal frequency-division multiplexing (OFDM, to increase throughput on the time and frequency selective channel. The adaptive turbo code scheme is based on a subband adaptive method, and compares two adaptive systems: a conventional approach where a separate turbo code is used for each subband, and a single turbo code adaptive system which uses a single turbo code over all subbands. Five modulation schemes (BPSK, QPSK, 8AMPM, 16QAM, and 64QAM are employed and turbo code rates considered are and . The performances of both systems with high ( and low ( BER targets are compared. Simulation results for throughput and BER show that the single turbo code adaptive system provides a significant improvement.

On the theories, techniques, and computer codes used in numerical reactor criticality and burnup calculations

International Nuclear Information System (INIS)

El-Osery, I.A.

1981-01-01

The purpose of this paper is to discuss the theories, techniques and computer codes that are frequently used in numerical reactor criticality and burnup calculations. It is a part of an integrated nuclear reactor calculation scheme conducted by the Reactors Department, Inshas Nuclear Research Centre. The crude part in numerical reactor criticality and burnup calculations includes the determination of neutron flux distribution which can be obtained in principle as a solution of Boltzmann transport equation. Numerical methods used for solving transport equations are discussed. Emphasis are made on numerical techniques based on multigroup diffusion theory. These numerical techniques include nodal, modal, and finite difference ones. The most commonly known computer codes utilizing these techniques are reviewed. Some of the main computer codes that have been already developed at the Reactors Department and related to numerical reactor criticality and burnup calculations have been presented

Incoherent scatter studies of upper atmosphere dynamics and coding technique

International Nuclear Information System (INIS)

Haeggstroem, Ingemar.

1990-09-01

Observations by the EISCAT incoherent scatter radar are used to study the dynamics of the auroral upper atmosphere. The study describes some effects of the strong plasma convection occurring at these latitudes and a new coding technique for incoherent scatter radars. A technique to determine the thermospheric neutral wind from incoherent scatter measurements is described. Simultaneous Fabry-Perot interferometer measurements of the wind are compared with those derived from the radar data. F-region electron density depletions in the afternoon/evening sector of the auroral zone, identified as the main ionospheric trough, are investigated. In a statistical study, based on wide latitude scanning experiment made at solar minimum, the trough appearance at a given latitude is compared to the geomagnetic index K p , and an empirical model predicting the latitude of the trough is proposed. Detailed studies, using different experiment modes, show that the equatorward edge of the auroral oval is co-located of up to 1 degree poleward of the trough minimum, which in turn is co-located with the peak convective electric field, with its boundary 1 degree - 2 degree equatorward of the trough minimum. It is shown that the F-region ion composition changes from pure 0 + to molecular ion dominated (NO + /O 2 + ) as the trough moves into the region probed by the radar. In a special case, where a geomagnetic sudden impulse caused an expansion of the plasma convection pattern, the equatorward trough progression is studied together with ionosonde measurements. A new coding technique for incoherent scatter radar measurement is introduced and described. The method, called alternating codes, provides significantly more accurate estimates of the plasma parameters than can be obtained by frequency commutated multipulse measurements. Simple explanations of the method are given as well as a precise definition. Two examples of application of the alternating codes are presented, showing the high

The histone codes for meiosis.

Science.gov (United States)

Wang, Lina; Xu, Zhiliang; Khawar, Muhammad Babar; Liu, Chao; Li, Wei

2017-09-01

Meiosis is a specialized process that produces haploid gametes from diploid cells by a single round of DNA replication followed by two successive cell divisions. It contains many special events, such as programmed DNA double-strand break (DSB) formation, homologous recombination, crossover formation and resolution. These events are associated with dynamically regulated chromosomal structures, the dynamic transcriptional regulation and chromatin remodeling are mainly modulated by histone modifications, termed 'histone codes'. The purpose of this review is to summarize the histone codes that are required for meiosis during spermatogenesis and oogenesis, involving meiosis resumption, meiotic asymmetric division and other cellular processes. We not only systematically review the functional roles of histone codes in meiosis but also discuss future trends and perspectives in this field. © 2017 Society for Reproduction and Fertility.

Improved BER based on intensity noise alleviation using developed detection technique for incoherent SAC-OCDMA systems

Science.gov (United States)

Al-Khafaji, Hamza M. R.; Aljunid, S. A.; Fadhil, Hilal A.

2012-06-01

The major drawback of incoherent spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems is their inherent intensity noise originating due to the incoherency of the broadband light sources. In this paper, we propose a developed detection technique named the modified-AND subtraction detection for incoherent SAC-OCDMA systems. This detection technique is based upon decreasing the received signal strength during the decoding process by dividing the spectrum of the utilized code sequence. The proposed technique is capable of mitigating the intensity noise effect, as well as suppressing the multiple-access interference impact. Based on modified quadratic congruence (MQC) code, the analytical results reveal that the modified-AND detection offer best bit-error rate (BER) performance and enables MQC code to support higher transmission rate up to 1.25 Gb/s compared to conventional AND detection. Furthermore, we ascertained that the proposed technique enhances the system performance using a simulation experiment.

Heterodyne detection using spectral line pairing for spectral phase encoding optical code division multiple access and dynamic dispersion compensation.

Science.gov (United States)

Yang, Yi; Foster, Mark; Khurgin, Jacob B; Cooper, A Brinton

2012-07-30

A novel coherent optical code-division multiple access (OCDMA) scheme is proposed that uses spectral line pairing to generate signals suitable for heterodyne decoding. Both signal and local reference are transmitted via a single optical fiber and a simple balanced receiver performs sourceless heterodyne detection, canceling speckle noise and multiple-access interference (MAI). To validate the idea, a 16 user fully loaded phase encoded system is simulated. Effects of fiber dispersion on system performance are studied as well. Both second and third order dispersion management is achieved by using a spectral phase encoder to adjust phase shifts of spectral components at the optical network unit (ONU).

PMD compensation in fiber-optic communication systems with direct detection using LDPC-coded OFDM.

Science.gov (United States)

Djordjevic, Ivan B

2007-04-02

The possibility of polarization-mode dispersion (PMD) compensation in fiber-optic communication systems with direct detection using a simple channel estimation technique and low-density parity-check (LDPC)-coded orthogonal frequency division multiplexing (OFDM) is demonstrated. It is shown that even for differential group delay (DGD) of 4/BW (BW is the OFDM signal bandwidth), the degradation due to the first-order PMD can be completely compensated for. Two classes of LDPC codes designed based on two different combinatorial objects (difference systems and product of combinatorial designs) suitable for use in PMD compensation are introduced.

Modified multiphotodiode balanced detection technique for improving SAC-OCDMA networks

Science.gov (United States)

Tseng, Shin-Pin

2015-06-01

The aim of this study was to develop a feasible modified multiphotodiode balanced detection (MMBD) technique suitable for application in spectral-amplitude-coding optical code-division multiple-access networks, which could mitigate the effect of phase-induced intensity noise (PIIN). Because PIIN is related to the beating between optical signals with wavelengths arriving simultaneously at a balanced photodetector, combining spectral partitioning and an MMBD scheme facilitates reducing PIIN, which tends to dominate performance. Therefore, the system using the proposed scheme exhibited an enhanced performance.

A review of spectrally coded multiplexing techniques for fibre grating sensor systems

International Nuclear Information System (INIS)

Childs, Paul; Wong, Allan C L; Yan, Binbin; Li, Mo; Peng, Gang-Ding

2010-01-01

We review recent work and progress on spectrally coded multiplexing (SCM). SCM is a generic multiplexing technique that provides more efficient data usage, additional flexibility and greater channel capability for fibre and fibre grating based sensor systems. We show a few examples of newly developed SCM techniques based on specially designed fibre gratings

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1980-09-01

Research activities in the Division of Reactor Engineering in fiscal 1979 are described. The work of the Division is closely related to development of multi-purpose Very High Temperature Gas Cooled Reactor and fusion reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and fusion reactor technology, and activities of the Committees on Reactor Physics and on Decomissioning of Nuclear Facilities. (author)

Scalable Video Coding with Interlayer Signal Decorrelation Techniques

Directory of Open Access Journals (Sweden)

Yang Wenxian

2007-01-01

Full Text Available Scalability is one of the essential requirements in the compression of visual data for present-day multimedia communications and storage. The basic building block for providing the spatial scalability in the scalable video coding (SVC standard is the well-known Laplacian pyramid (LP. An LP achieves the multiscale representation of the video as a base-layer signal at lower resolution together with several enhancement-layer signals at successive higher resolutions. In this paper, we propose to improve the coding performance of the enhancement layers through efficient interlayer decorrelation techniques. We first show that, with nonbiorthogonal upsampling and downsampling filters, the base layer and the enhancement layers are correlated. We investigate two structures to reduce this correlation. The first structure updates the base-layer signal by subtracting from it the low-frequency component of the enhancement layer signal. The second structure modifies the prediction in order that the low-frequency component in the new enhancement layer is diminished. The second structure is integrated in the JSVM 4.0 codec with suitable modifications in the prediction modes. Experimental results with some standard test sequences demonstrate coding gains up to 1 dB for I pictures and up to 0.7 dB for both I and P pictures.

A multi coding technique to reduce transition activity in VLSI circuits

International Nuclear Information System (INIS)

Vithyalakshmi, N.; Rajaram, M.

2014-01-01

Advances in VLSI technology have enabled the implementation of complex digital circuits in a single chip, reducing system size and power consumption. In deep submicron low power CMOS VLSI design, the main cause of energy dissipation is charging and discharging of internal node capacitances due to transition activity. Transition activity is one of the major factors that also affect the dynamic power dissipation. This paper proposes power reduction analyzed through algorithm and logic circuit levels. In algorithm level the key aspect of reducing power dissipation is by minimizing transition activity and is achieved by introducing a data coding technique. So a novel multi coding technique is introduced to improve the efficiency of transition activity up to 52.3% on the bus lines, which will automatically reduce the dynamic power dissipation. In addition, 1 bit full adders are introduced in the Hamming distance estimator block, which reduces the device count. This coding method is implemented using Verilog HDL. The overall performance is analyzed by using Modelsim and Xilinx Tools. In total 38.2% power saving capability is achieved compared to other existing methods. (semiconductor technology)

Separate Turbo Code and Single Turbo Code Adaptive OFDM Transmissions

Directory of Open Access Journals (Sweden)

Lei Ye

2009-01-01

Full Text Available This paper discusses the application of adaptive modulation and adaptive rate turbo coding to orthogonal frequency-division multiplexing (OFDM, to increase throughput on the time and frequency selective channel. The adaptive turbo code scheme is based on a subband adaptive method, and compares two adaptive systems: a conventional approach where a separate turbo code is used for each subband, and a single turbo code adaptive system which uses a single turbo code over all subbands. Five modulation schemes (BPSK, QPSK, 8AMPM, 16QAM, and 64QAM are employed and turbo code rates considered are 1/2 and 1/3. The performances of both systems with high (10−2 and low (10−4 BER targets are compared. Simulation results for throughput and BER show that the single turbo code adaptive system provides a significant improvement.

Progress report of Applied Physics Division. 1 October 1980 - 30 June 1981. Acting Division Chief - Dr. J. Parry

International Nuclear Information System (INIS)

2004-01-01

In September 1980, the Commission approved a reorganization of Physics Division, Engineering Research Division and Instrumentation and Control Division to form two new research divisions to be known as Applied Physics Division and Nuclear Technology Division. The Applied Physics Division will be responsible for applied science programs, particularly those concerned with nuclear techniques. The Division is organized as four sections with the following responsibilities: (1) Nuclear Applications and Energy Studies Section. Program includes studies in nuclear physics, nuclear applications, ion implantation and neutron scattering. (2) Semiconductor and Radiation Physics Section. Studies in semiconductor radiation detectors, radiation standards and laser applications. (3) Electronic Systems Section. This includes systems analysis, digital systems, instrument design, project instrumentation and instrument maintenance. (4) Fusion Physics Section. This covers work carried out by staff currently attached to university groups (author)

Bit Plane Coding based Steganography Technique for JPEG2000 Images and Videos

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Geeta Kasana

2016-02-01

Full Text Available In this paper, a Bit Plane Coding (BPC based steganography technique for JPEG2000 images and Motion JPEG2000 video is proposed. Embedding in this technique is performed in the lowest significant bit planes of the wavelet coefficients of a cover image. In JPEG2000 standard, the number of bit planes of wavelet coefficients to be used in encoding is dependent on the compression rate and are used in Tier-2 process of JPEG2000. In the proposed technique, Tier-1 and Tier-2 processes of JPEG2000 and Motion JPEG2000 are executed twice on the encoder side to collect the information about the lowest bit planes of all code blocks of a cover image, which is utilized in embedding and transmitted to the decoder. After embedding secret data, Optimal Pixel Adjustment Process (OPAP is applied on stego images to enhance its visual quality. Experimental results show that proposed technique provides large embedding capacity and better visual quality of stego images than existing steganography techniques for JPEG2000 compressed images and videos. Extracted secret image is similar to the original secret image.

Tag-to-Tag Interference Suppression Technique Based on Time Division for RFID

Directory of Open Access Journals (Sweden)

Grishma Khadka

2017-01-01

Full Text Available Radio-frequency identification (RFID is a tracking technology that enables immediate automatic object identification and rapid data sharing for a wide variety of modern applications using radio waves for data transmission from a tag to a reader. RFID is already well established in technical areas, and many companies have developed corresponding standards and measurement techniques. In the construction industry, effective monitoring of materials and equipment is an important task, and RFID helps to improve monitoring and controlling capabilities, in addition to enabling automation for construction projects. However, on construction sites, there are many tagged objects and multiple RFID tags that may interfere with each other’s communications. This reduces the reliability and efficiency of the RFID system. In this paper, we propose an anti-collision algorithm for communication between multiple tags and a reader. In order to suppress interference signals from multiple neighboring tags, the proposed algorithm employs the time-division (TD technique, where tags in the interrogation zone are assigned a specific time slot so that at every instance in time, a reader communicates with tags using the specific time slot. We present representative computer simulation examples to illustrate the performance of the proposed anti-collision technique for multiple RFID tags.

Hybrid PAPR reduction scheme with Huffman coding and DFT-spread technique for direct-detection optical OFDM systems

Science.gov (United States)

Peng, Miao; Chen, Ming; Zhou, Hui; Wan, Qiuzhen; Jiang, LeYong; Yang, Lin; Zheng, Zhiwei; Chen, Lin

2018-01-01

High peak-to-average power ratio (PAPR) of the transmit signal is a major drawback in optical orthogonal frequency division multiplexing (OOFDM) system. In this paper, we propose and experimentally demonstrate a novel hybrid scheme, combined the Huffman coding and Discrete Fourier Transmission-Spread (DFT-spread), in order to reduce high PAPR in a 16-QAM short-reach intensity-modulated and direct-detection OOFDM (IMDD-OOFDM) system. The experimental results demonstrated that the hybrid scheme can reduce the PAPR by about 1.5, 2, 3 and 6 dB, and achieve 1.5, 1, 2.5 and 3 dB receiver sensitivity improvement compared to clipping, DFT-spread and Huffman coding and original OFDM signals, respectively, at an error vector magnitude (EVM) of -10 dB after transmission over 20 km standard single-mode fiber (SSMF). Furthermore, the throughput gain can be of the order of 30% by using the hybrid scheme compared with the cases of without applying the Huffman coding.

Multiple Access Techniques for Next Generation Wireless: Recent Advances and Future Perspectives

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Shree Krishna Sharma

2016-01-01

Full Text Available The advances in multiple access techniques has been one of the key drivers in moving from one cellular generation to another. Starting from the first generation, several multiple access techniques have been explored in different generations and various emerging multiplexing/multiple access techniques are being investigated for the next generation of cellular networks. In this context, this paper first provides a detailed review on the existing Space Division Multiple Access (SDMA related works. Subsequently, it highlights the main features and the drawbacks of various existing and emerging multiplexing/multiple access techniques. Finally, we propose a novel concept of clustered orthogonal signature division multiple access for the next generation of cellular networks. The proposed concept envisions to employ joint antenna coding in order to enhance the orthogonality of SDMA beams with the objective of enhancing the spectral efficiency of future cellular networks.

The effect of total noise on two-dimension OCDMA codes

Science.gov (United States)

Dulaimi, Layth A. Khalil Al; Badlishah Ahmed, R.; Yaakob, Naimah; Aljunid, Syed A.; Matem, Rima

2017-11-01

In this research, we evaluate the performance of total noise effect on two dimension (2-D) optical code-division multiple access (OCDMA) performance systems using 2-D Modified Double Weight MDW under various link parameters. The impact of the multi-access interference (MAI) and other noise effect on the system performance. The 2-D MDW is compared mathematically with other codes which use similar techniques. We analyzed and optimized the data rate and effective receive power. The performance and optimization of MDW code in OCDMA system are reported, the bit error rate (BER) can be significantly improved when the 2-D MDW code desired parameters are selected especially the cross correlation properties. It reduces the MAI in the system compensate BER and phase-induced intensity noise (PIIN) in incoherent OCDMA The analysis permits a thorough understanding of PIIN, shot and thermal noises impact on 2-D MDW OCDMA system performance. PIIN is the main noise factor in the OCDMA network.

The effect of total noise on two-dimension OCDMA codes

Directory of Open Access Journals (Sweden)

Khalil Al Dulaimi Layth A.

2017-01-01

Full Text Available In this research, we evaluate the performance of total noise effect on two dimension (2-D optical code-division multiple access (OCDMA performance systems using 2-D Modified Double Weight MDW under various link parameters. The impact of the multi-access interference (MAI and other noise effect on the system performance. The 2-D MDW is compared mathematically with other codes which use similar techniques. We analyzed and optimized the data rate and effective receive power. The performance and optimization of MDW code in OCDMA system are reported, the bit error rate (BER can be significantly improved when the 2-D MDW code desired parameters are selected especially the cross correlation properties. It reduces the MAI in the system compensate BER and phase-induced intensity noise (PIIN in incoherent OCDMA The analysis permits a thorough understanding of PIIN, shot and thermal noises impact on 2-D MDW OCDMA system performance. PIIN is the main noise factor in the OCDMA network.

An In vitro evaluation of the reliability of QR code denture labeling technique.

Science.gov (United States)

Poovannan, Sindhu; Jain, Ashish R; Krishnan, Cakku Jalliah Venkata; Chandran, Chitraa R

2016-01-01

Positive identification of the dead after accidents and disasters through labeled dentures plays a key role in forensic scenario. A number of denture labeling methods are available, and studies evaluating their reliability under drastic conditions are vital. This study was conducted to evaluate the reliability of QR (Quick Response) Code labeled at various depths in heat-cured acrylic blocks after acid treatment, heat treatment (burns), and fracture in forensics. It was an in vitro study. This study included 160 specimens of heat-cured acrylic blocks (1.8 cm × 1.8 cm) and these were divided into 4 groups (40 samples per group). QR Codes were incorporated in the samples using clear acrylic sheet and they were assessed for reliability under various depths, acid, heat, and fracture. Data were analyzed using Chi-square test, test of proportion. The QR Code inclusion technique was reliable under various depths of acrylic sheet, acid (sulfuric acid 99%, hydrochloric acid 40%) and heat (up to 370°C). Results were variable with fracture of QR Code labeled acrylic blocks. Within the limitations of the study, by analyzing the results, it was clearly indicated that the QR Code technique was reliable under various depths of acrylic sheet, acid, and heat (370°C). Effectiveness varied in fracture and depended on the level of distortion. This study thus suggests that QR Code is an effective and simpler denture labeling method.

Group-Orthogonal Code-Division Multiplex: A Physical-Layer Enhancement for IEEE 802.11n Networks

Directory of Open Access Journals (Sweden)

Felip Riera-Palou

2010-01-01

Full Text Available The new standard for wireless local area networks (WLANs, named IEEE 802.11n, has been recently released. This new norm builds upon and remains compatible with the previous WLANs standards IEEE 802.11a/g while it is able to achieve transmission rates of up to 600 Mbps. These increased data rates are mainly a consequence of two important new features: (1 multiple antenna technology at transmission and reception, and (2 optional doubling of the system bandwidth thanks to the availability of an additional 20 MHz band. This paper proposes the use of Group-Orthogonal Code Division Multiplex (GO-CDM as a means to improve the performance of the 802.11n standard by further exploiting the inherent frequency diversity. It is explained why GO-CDM synergistically matches with the two aforementioned new features and the performance gains it can offer under different configurations is illustrated. Furthermore, the effects that group-orthogonal has on key implementation issues such as channel estimation, carrier frequency offset, and peak-to-average power ratio (PAPR are also considered.

Reply to "Comments on Techniques and Architectures for Hazard-Free Semi-Parallel Decoding of LDPC Codes"

Directory of Open Access Journals (Sweden)

Rovini Massimo

2009-01-01

Full Text Available This is a reply to the comments by Gunnam et al. "Comments on 'Techniques and architectures for hazard-free semi-parallel decoding of LDPC codes'", EURASIP Journal on Embedded Systems, vol. 2009, Article ID 704174 on our recent work "Techniques and architectures for hazard-free semi-parallel decoding of LDPC codes", EURASIP Journal on Embedded Systems, vol. 2009, Article ID 723465.

Zero-forcing pre-coding for MIMO WiMAX transceivers: Performance analysis and implementation issues

Science.gov (United States)

Cattoni, A. F.; Le Moullec, Y.; Sacchi, C.

Next generation wireless communication networks are expected to achieve ever increasing data rates. Multi-User Multiple-Input-Multiple-Output (MU-MIMO) is a key technique to obtain the expected performance, because such a technique combines the high capacity achievable using MIMO channel with the benefits of space division multiple access. In MU-MIMO systems, the base stations transmit signals to two or more users over the same channel, for this reason every user can experience inter-user interference. This paper provides a capacity analysis of an online, interference-based pre-coding algorithm able to mitigate the multi-user interference of the MU-MIMO systems in the context of a realistic WiMAX application scenario. Simulation results show that pre-coding can significantly increase the channel capacity. Furthermore, the paper presents several feasibility considerations for implementation of the analyzed technique in a possible FPGA-based software defined radio.

A new two dimensional spectral/spatial multi-diagonal code for noncoherent optical code division multiple access (OCDMA) systems

Science.gov (United States)

Kadhim, Rasim Azeez; Fadhil, Hilal Adnan; Aljunid, S. A.; Razalli, Mohamad Shahrazel

2014-10-01

A new two dimensional codes family, namely two dimensional multi-diagonal (2D-MD) codes, is proposed for spectral/spatial non-coherent OCDMA systems based on the one dimensional MD code. Since the MD code has the property of zero cross correlation, the proposed 2D-MD code also has this property. So that, the multi-access interference (MAI) is fully eliminated and the phase induced intensity noise (PIIN) is suppressed with the proposed code. Code performance is analyzed in terms of bit error rate (BER) while considering the effect of shot noise, PIIN, and thermal noise. The performance of the proposed code is compared with the related MD, modified quadratic congruence (MQC), two dimensional perfect difference (2D-PD) and two dimensional diluted perfect difference (2D-DPD) codes. The analytical and the simulation results reveal that the proposed 2D-MD code outperforms the other codes. Moreover, a large number of simultaneous users can be accommodated at low BER and high data rate.

Eliminating four-wave-mixing crosstalk in wavelength-division-multiplexing systems

Science.gov (United States)

Kwong, Wing C.; Yang, Guu-Chang

1996-11-01

To reduce four-wave-mixing crosstalk in long-haul wavelength-division multiplexing (WDM) lightwave systems, the use of unequally spaced channels has recently been proposed. Instead of being solved y integer linear programming, the unequal-spaced channel-allocation problem is here treated as constructing suitable optical orthogonal codes in optical code-division multiple-access (CDMA). Three 'algebraic' algorithms on finding the frequency locations of unequally spaced WDM channels are reported. The constructions are based on generating optical CDMA codewords with a predetermined pulse separation and 'aperiodic' autocorrelation sidelobes no greater than one. The algorithms potentially provide a fast and simple alternative to solve the problem, besides the recently reported computer-search method.

When are network coding based dynamic multi-homing techniques beneficial?

DEFF Research Database (Denmark)

Pereira, Carlos; Aguiar, Ana; Roetter, Daniel Enrique Lucani

2016-01-01

Mechanisms that can cope with unreliable wireless channels in an efficient manner are required due to the increasing number of resource constrained devices. Concurrent use of multiple communications technologies can be instrumental towards improving services to mobile devices in heterogeneous...... networks. In our previous work, we developed an optimization framework to generate channel-aware transmission policies for multi-homed devices under different cost criteria. Our formulation considers network coding as a key technique that simplifies load allocation across multiple channels and provides...... high resiliency under time-varying channel conditions. This paper seeks to explore the parameter space and identify the operating regions where dynamic coded policies offer most improvement over static ones in terms of energy consumption and channel utilization. We leverage meta-heuristics to find...

Detonation of high explosives in Lagrangian hydrodynamic codes using the programmed burn technique

International Nuclear Information System (INIS)

Berger, M.E.

1975-09-01

Two initiation methods were developed for improving the programmed burn technique for detonation of high explosives in smeared-shock Lagrangian hydrodynamic codes. The methods are verified by comparing the improved programmed burn with existing solutions in one-dimensional plane, converging, and diverging geometries. Deficiencies in the standard programmed burn are described. One of the initiation methods has been determined to be better for inclusion in production hydrodynamic codes

Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1975-02-01

This report summarizes main research achievements in the 48th fiscal year which were made by Reactor Engineering Division consisted of eight laboratories and Computing Center. The major research and development projects, with which the research programmes in the Division are associated, are development of High Temperature Gas Cooled Reactor for multi-purpose use, development of Liquid Metal Fast Breeder Reactor conducted by Power Reactor and Nuclear Fuel Development Corporation, and Engineering Research Programme for Thermonuclear Fusion Reactor. Many achievements are reported in various research items such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, heat transfer and fluid dynamics, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology and activities of Computing Center. (auth.)

Reactor Systems Technology Division code development and configuration/quality control procedures

International Nuclear Information System (INIS)

Johnson, E.C.

1985-06-01

Procedures are prescribed for executing a code development task and implementing the resulting coding in an official version of a computer code. The responsibilities of the project manager, development staff members, and the Code Configuration/Quality Control Group are defined. Examples of forms, logs, computer job control language, and suggested outlines for reports associated with software production and implementation are included in Appendix A. 1 raf., 2 figs

Application and analysis of performance of dqpsk advanced modulation format in spectral amplitude coding ocdma

International Nuclear Information System (INIS)

Memon, A.

2015-01-01

SAC (Spectral Amplitude Coding) is a technique of OCDMA (Optical Code Division Multiple Access) to encode and decode data bits by utilizing spectral components of the broadband source. Usually OOK (ON-Off-Keying) modulation format is used in this encoding scheme. To make SAC OCDMA network spectrally efficient, advanced modulation format of DQPSK (Differential Quaternary Phase Shift Keying) is applied, simulated and analyzed, m-sequence code is encoded in the simulated setup. Performance regarding various lengths of m-sequence code is also analyzed and displayed in the pictorial form. The results of the simulation are evaluated with the help of electrical constellation diagram, eye diagram and bit error rate graph. All the graphs indicate better transmission quality in case of advanced modulation format of DQPSK used in SAC OCDMA network as compared with OOK. (author)

A New Image Encryption Technique Combining Hill Cipher Method, Morse Code and Least Significant Bit Algorithm

Science.gov (United States)

Nofriansyah, Dicky; Defit, Sarjon; Nurcahyo, Gunadi W.; Ganefri, G.; Ridwan, R.; Saleh Ahmar, Ansari; Rahim, Robbi

2018-01-01

Cybercrime is one of the most serious threats. Efforts are made to reduce the number of cybercrime is to find new techniques in securing data such as Cryptography, Steganography and Watermarking combination. Cryptography and Steganography is a growing data security science. A combination of Cryptography and Steganography is one effort to improve data integrity. New techniques are used by combining several algorithms, one of which is the incorporation of hill cipher method and Morse code. Morse code is one of the communication codes used in the Scouting field. This code consists of dots and lines. This is a new modern and classic concept to maintain data integrity. The result of the combination of these three methods is expected to generate new algorithms to improve the security of the data, especially images.

Optimized and secure technique for multiplexing QR code images of single characters: application to noiseless messages retrieval

International Nuclear Information System (INIS)

Trejos, Sorayda; Barrera, John Fredy; Torroba, Roberto

2015-01-01

We present for the first time an optical encrypting–decrypting protocol for recovering messages without speckle noise. This is a digital holographic technique using a 2f scheme to process QR codes entries. In the procedure, letters used to compose eventual messages are individually converted into a QR code, and then each QR code is divided into portions. Through a holographic technique, we store each processed portion. After filtering and repositioning, we add all processed data to create a single pack, thus simplifying the handling and recovery of multiple QR code images, representing the first multiplexing procedure applied to processed QR codes. All QR codes are recovered in a single step and in the same plane, showing neither cross-talk nor noise problems as in other methods. Experiments have been conducted using an interferometric configuration and comparisons between unprocessed and recovered QR codes have been performed, showing differences between them due to the involved processing. Recovered QR codes can be successfully scanned, thanks to their noise tolerance. Finally, the appropriate sequence in the scanning of the recovered QR codes brings a noiseless retrieved message. Additionally, to procure maximum security, the multiplexed pack could be multiplied by a digital diffuser as to encrypt it. The encrypted pack is easily decoded by multiplying the multiplexing with the complex conjugate of the diffuser. As it is a digital operation, no noise is added. Therefore, this technique is threefold robust, involving multiplexing, encryption, and the need of a sequence to retrieve the outcome. (paper)

Optimized and secure technique for multiplexing QR code images of single characters: application to noiseless messages retrieval

Science.gov (United States)

Trejos, Sorayda; Fredy Barrera, John; Torroba, Roberto

2015-08-01

We present for the first time an optical encrypting-decrypting protocol for recovering messages without speckle noise. This is a digital holographic technique using a 2f scheme to process QR codes entries. In the procedure, letters used to compose eventual messages are individually converted into a QR code, and then each QR code is divided into portions. Through a holographic technique, we store each processed portion. After filtering and repositioning, we add all processed data to create a single pack, thus simplifying the handling and recovery of multiple QR code images, representing the first multiplexing procedure applied to processed QR codes. All QR codes are recovered in a single step and in the same plane, showing neither cross-talk nor noise problems as in other methods. Experiments have been conducted using an interferometric configuration and comparisons between unprocessed and recovered QR codes have been performed, showing differences between them due to the involved processing. Recovered QR codes can be successfully scanned, thanks to their noise tolerance. Finally, the appropriate sequence in the scanning of the recovered QR codes brings a noiseless retrieved message. Additionally, to procure maximum security, the multiplexed pack could be multiplied by a digital diffuser as to encrypt it. The encrypted pack is easily decoded by multiplying the multiplexing with the complex conjugate of the diffuser. As it is a digital operation, no noise is added. Therefore, this technique is threefold robust, involving multiplexing, encryption, and the need of a sequence to retrieve the outcome.

Chemical Sciences Division: Annual report 1992

International Nuclear Information System (INIS)

1993-10-01

The Chemical Sciences Division (CSD) is one of twelve research Divisions of the Lawrence Berkeley Laboratory, a Department of Energy National Laboratory. The CSD is composed of individual groups and research programs that are organized into five scientific areas: Chemical Physics, Inorganic/Organometallic Chemistry, Actinide Chemistry, Atomic Physics, and Physical Chemistry. This report describes progress by the CSD for 1992. Also included are remarks by the Division Director, a description of work for others (United States Office of Naval Research), and appendices of the Division personnel and an index of investigators. Research reports are grouped as Fundamental Interactions (Photochemical and Radiation Sciences, Chemical Physics, Atomic Physics) or Processes and Techniques (Chemical Energy, Heavy-Element Chemistry, and Chemical Engineering Sciences)

32 X 2.5 Gb/s Optical Code Division Multiplexing (O-CDM) For Agile Optical Networking (Phase II) Final Report CRADA No. TC02051.0

Energy Technology Data Exchange (ETDEWEB)

Bennett, C. V. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Mendez, A. J. [Mendez R & D Associates, El Segundo, CA (United States)

2017-09-08

This was a collaborative effort between Lawrence Livermore National Security, LLC (formerly The Regents of the University of California)/Lawrence Livermore National Laboratory (LLNL) and Mendez R & D Associates (MRDA) to develop and demonstrate a reconfigurable and cost effective design for optical code division multiplexing (O-CDM) with high spectral efficiency and throughput, as applied to the field of distributed computing, including multiple accessing (sharing of communication resources) and bidirectional data distribution in fiber-to-the-premise (FTTx) networks.

An overview of data acquisition, signal coding and data analysis techniques for MST radars

Science.gov (United States)

Rastogi, P. K.

1986-01-01

An overview is given of the data acquisition, signal processing, and data analysis techniques that are currently in use with high power MST/ST (mesosphere stratosphere troposphere/stratosphere troposphere) radars. This review supplements the works of Rastogi (1983) and Farley (1984) presented at previous MAP workshops. A general description is given of data acquisition and signal processing operations and they are characterized on the basis of their disparate time scales. Then signal coding, a brief description of frequently used codes, and their limitations are discussed, and finally, several aspects of statistical data processing such as signal statistics, power spectrum and autocovariance analysis, outlier removal techniques are discussed.

Above the nominal limit performance evaluation of multiwavelength optical code-division multiple-access systems

Science.gov (United States)

Inaty, Elie; Raad, Robert; Fortier, Paul; Shalaby, Hossam M. H.

2009-03-01

We provide an analysis for the performance of a multiwavelength optical code-division multiple-access (MW-OCDMA) network when the system is working above the nominal transmission rate limit imposed by passive encoding-decoding operation. We address the problem of overlapping in such a system and how it can directly affect the bit error rate (BER). A unified mathematical framework is presented under the assumption of one-coincidence sequences with nonrepeating wavelengths. A closed form expression of the multiple access interference limited BER is provided as a function of different system parameters. Results show that the performance of the MW-OCDMA system can be critically affected when working above the nominal limit, an event that can happen when the network operates at a high transmission rate. In addition, the impact of the derived error probability on the performance of two newly proposed medium access control (MAC) protocols, the S-ALOHA and the R3T, is also investigated. It is shown that for low transmission rates, the S-ALOHA is better than the R3T, while the R3T is better at very high transmission rates. In general, it is postulated that the R3T protocol suffers a higher delay mainly because of the presence of additional modes.

Differential Service in a Bidirectional Radio-over-Fiber System over a Spectral-Amplitude-Coding OCDMA Network

Directory of Open Access Journals (Sweden)

Chao-Chin Yang

2016-10-01

Full Text Available A new scheme of radio-over-fiber (RoF network based on spectral-amplitude-coding (SAC optical code division multiple access (OCDMA is herein proposed. Differential service is provided by a power control scheme that classifies users into several classes and assigns each of them with a specific power level. Additionally, the wavelength reuse technique is adapted to support bidirectional transmission and reduce base station (BS cost. Both simulation and numerical results show that significantly differential quality-of-service (QoS in bit-error rate (BER is achieved in both downlink and uplink transmissions.

Distributed Source Coding Techniques for Lossless Compression of Hyperspectral Images

Directory of Open Access Journals (Sweden)

Barni Mauro

2007-01-01

Full Text Available This paper deals with the application of distributed source coding (DSC theory to remote sensing image compression. Although DSC exhibits a significant potential in many application fields, up till now the results obtained on real signals fall short of the theoretical bounds, and often impose additional system-level constraints. The objective of this paper is to assess the potential of DSC for lossless image compression carried out onboard a remote platform. We first provide a brief overview of DSC of correlated information sources. We then focus on onboard lossless image compression, and apply DSC techniques in order to reduce the complexity of the onboard encoder, at the expense of the decoder's, by exploiting the correlation of different bands of a hyperspectral dataset. Specifically, we propose two different compression schemes, one based on powerful binary error-correcting codes employed as source codes, and one based on simpler multilevel coset codes. The performance of both schemes is evaluated on a few AVIRIS scenes, and is compared with other state-of-the-art 2D and 3D coders. Both schemes turn out to achieve competitive compression performance, and one of them also has reduced complexity. Based on these results, we highlight the main issues that are still to be solved to further improve the performance of DSC-based remote sensing systems.

Annual report of the Division of High Temperature Engineering

International Nuclear Information System (INIS)

1982-10-01

Research activities conducted in the Division of High Temperature Engineering during fiscal 1981 are described. R and D works of our division are mainly related to a multi-purpose very high-temperature gas-cooled reactor (VHTR) and a fusion reactor. This report deals with the main results obtained on material test, development of computer codes, heat transfer, fluid-dynamics, structural mechanics and the construction of an M + A (Mother and Adapter) section of a HENDEL (Helium Engineering Demonstration Loop) as well. (author)

The Analysis of Dimensionality Reduction Techniques in Cryptographic Object Code Classification

Energy Technology Data Exchange (ETDEWEB)

Jason L. Wright; Milos Manic

2010-05-01

This paper compares the application of three different dimension reduction techniques to the problem of locating cryptography in compiled object code. A simple classi?er is used to compare dimension reduction via sorted covariance, principal component analysis, and correlation-based feature subset selection. The analysis concentrates on the classi?cation accuracy as the number of dimensions is increased.

FERD and FERDOR type unfolding codes

International Nuclear Information System (INIS)

Burrus, W.R.

1976-01-01

FERD and FERDO are unfolding codes which were developed at the Neutron Physics Division of Oak Ridge National Laboratory in 1965 and 1966. FERDO variants such as FERDOR and FORIST have been widely used, and many useful supplementary procedures have been developed for neutron and gamma-ray spectroscopy and other diverse applications. Algorithms for the codes are discussed

Comparison of a Ring On-Chip Network and a Code-Division Multiple-Access On-Chip Network

Directory of Open Access Journals (Sweden)

Xin Wang

2007-01-01

Full Text Available Two network-on-chip (NoC designs are examined and compared in this paper. One design applies a bidirectional ring connection scheme, while the other design applies a code-division multiple-access (CDMA connection scheme. Both of the designs apply globally asynchronous locally synchronous (GALS scheme in order to deal with the issue of transferring data in a multiple-clock-domain environment of an on-chip system. The two NoC designs are compared with each other by their network structures, data transfer principles, network node structures, and their asynchronous designs. Both the synchronous and the asynchronous designs of the two on-chip networks are realized using a hardware-description language (HDL in order to make the entire designs suit the commonly used synchronous design tools and flow. The performance estimation and comparison of the two NoC designs which are based on the HDL realizations are addressed. By comparing the two NoC designs, the advantages and disadvantages of applying direct connection and CDMA connection schemes in an on-chip communication network are discussed.

Nuclear Physics Division progress report

International Nuclear Information System (INIS)

West, D.; Cookson, J.A.; Findlay, D.J.S.

1984-06-01

The 1983 progress report of the Nuclear Physics Division, UKAEA Harwell, is divided into four main topics. These are a) nuclear data and technology for nuclear power; b) nuclear studies; c) applications of nuclear and associated techniques, including ion beam techniques and moessbauer spectroscopy; and d) accelerator operation, maintenance and development. (U.K.)

Application and Analysis of Performance of DQPSK Advanced Modulation Format in Spectral Amplitude Coding OCDMA

Directory of Open Access Journals (Sweden)

Abdul Latif Memon

2014-04-01

Full Text Available SAC (Spectral Amplitude Coding is a technique of OCDMA (Optical Code Division Multiple Access to encode and decode data bits by utilizing spectral components of the broadband source. Usually OOK (ON-Off-Keying modulation format is used in this encoding scheme. To make SAC OCDMA network spectrally efficient, advanced modulation format of DQPSK (Differential Quaternary Phase Shift Keying is applied, simulated and analyzed. m-sequence code is encoded in the simulated setup. Performance regarding various lengths of m-sequence code is also analyzed and displayed in the pictorial form. The results of the simulation are evaluated with the help of electrical constellation diagram, eye diagram and bit error rate graph. All the graphs indicate better transmission quality in case of advanced modulation format of DQPSK used in SAC OCDMA network as compared with OOK

50th Anniversary of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture

International Nuclear Information System (INIS)

2015-01-01

The occasion of the 50th anniversary of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has again been an exceedingly productive year. In addition to our ongoing activities reported extensively in this volume, we have taken this opportunity to highlight several examples of tangible, sustainable results derived out of this unique partnership – beneficial to both our parent organizations and to our Member States – and to share these with our many stakeholders around the world and at the celebratory ceremony of this partnership. The enormous contributions of the Joint FAO/IAEA Division and its numerous stakeholders worldwide to meet the changing needs of Member States through the peaceful uses of nuclear technologies are today clearly demonstrated in the shared goals of our two parent organizations and in the five strategic objectives of the FAO: to help eliminate hunger, food insecurity and malnutrition; to make agriculture, forestry and fisheries more productive and sustainable; to reduce rural poverty; to enable inclusive and efficient agricultural and food systems; and to increase the resilience of livelihood to disaster

Mapping Urban Social Divisions

Directory of Open Access Journals (Sweden)

Susan Ball

2010-05-01

Full Text Available Against the background of increased levels of interest in space and images beyond the field of geography, this article (re- introduces earlier work on the semiotics of maps undertaken by geographers in the 1960s. The data limitations, purpose and cultural context in which a user interprets a map's codes and conventions are highlighted in this work, which remains relevant to the interpretation of maps—new and old—forty years later. By means of drawing on geography's contribution to the semiotics of maps, the article goes on to examine the concept of urban social divisions as represented in map images. Using a small number of map images, including two of the most widely known maps of urban social division in Europe and North America, the roles of context, data and purpose in the production and interpretation of maps are discussed. By presenting the examples chronologically the article shows that although advances in data collection and manipulation have allowed researchers to combine different social variables in maps of social division, and to interact with map images, work by geographers on the semiotics of maps is no less relevant today than when it was first proposed forty years ago. URN: urn:nbn:de:0114-fqs1002372

On Applicability of Network Coding Technique for 6LoWPAN-based Sensor Networks.

Science.gov (United States)

Amanowicz, Marek; Krygier, Jaroslaw

2018-05-26

In this paper, the applicability of the network coding technique in 6LoWPAN-based sensor multihop networks is examined. The 6LoWPAN is one of the standards proposed for the Internet of Things architecture. Thus, we can expect the significant growth of traffic in such networks, which can lead to overload and decrease in the sensor network lifetime. The authors propose the inter-session network coding mechanism that can be implemented in resource-limited sensor motes. The solution reduces the overall traffic in the network, and in consequence, the energy consumption is decreased. Used procedures take into account deep header compressions of the native 6LoWPAN packets and the hop-by-hop changes of the header structure. Applied simplifications reduce signaling traffic that is typically occurring in network coding deployments, keeping the solution usefulness for the wireless sensor networks with limited resources. The authors validate the proposed procedures in terms of end-to-end packet delay, packet loss ratio, traffic in the air, total energy consumption, and network lifetime. The solution has been tested in a real wireless sensor network. The results confirm the efficiency of the proposed technique, mostly in delay-tolerant sensor networks.

Partial Fingerprint Image Enhancement using Region Division Technique and Morphological Transform

International Nuclear Information System (INIS)

Ahmad, A.; Arshad, I.; Raja, G.

2015-01-01

Fingerprints are the most renowned biometric trait for identification and verification. The quality of fingerprint image plays a vital role in feature extraction and matching. Existing algorithms work well for good quality fingerprint images and fail for partial fingerprint images as they are obtained from excessively dry fingers or affected by disease resulting in broken ridges. We propose an algorithm to enhance partial fingerprint images using morphological operatins with region division technique. The proposed method divides low quality image into six regions from top to bottom. Morphological operations choose an appropriate Structuring Element (SE) that joins broken ridges and thus enhance the image for further processing. The proposed method uses SE line with suitable angle theta and radius r in each region based on the orientation of the ridges. The algorithm is applied to 14 low quality fingerprint images from FVC-2002 database. Experimental results show that percentage accuracy has been improved using the proposed algorithm. The manual markup has been reduced and accuracy of 76.16% with Equal Error Rate (EER) of 3.16% is achieved. (author)

Simultaneous chromatic dispersion and PMD compensation by using coded-OFDM and girth-10 LDPC codes.

Science.gov (United States)

Djordjevic, Ivan B; Xu, Lei; Wang, Ting

2008-07-07

Low-density parity-check (LDPC)-coded orthogonal frequency division multiplexing (OFDM) is studied as an efficient coded modulation scheme suitable for simultaneous chromatic dispersion and polarization mode dispersion (PMD) compensation. We show that, for aggregate rate of 10 Gb/s, accumulated dispersion over 6500 km of SMF and differential group delay of 100 ps can be simultaneously compensated with penalty within 1.5 dB (with respect to the back-to-back configuration) when training sequence based channel estimation and girth-10 LDPC codes of rate 0.8 are employed.

Application of data analysis techniques to nuclear reactor systems code to accuracy assessment

International Nuclear Information System (INIS)

Kunz, R.F.; Kasmala, G.F.; Murray, C.J.; Mahaffy, J.H.

2000-01-01

An automated code assessment program (ACAP) has been developed by the authors to provide quantitative comparisons between nuclear reactor systems (NRS) code results and experimental measurements. This software was developed under subcontract to the United States Nuclear Regulatory Commission for use in its NRS code consolidation efforts. In this paper, background on the topic of NRS accuracy and uncertainty assessment is provided which motivates the development of and defines basic software requirements for ACAP. A survey of data analysis techniques was performed, focusing on the applicability of methods in the construction of NRS code-data comparison measures. The results of this review process, which further defined the scope, user interface and process for using ACAP are also summarized. A description of the software package and several sample applications to NRS data sets are provided. Its functionality and ability to provide objective accuracy assessment figures are demonstrated. (author)

Iterative optimization of performance libraries by hierarchical division of codes

International Nuclear Information System (INIS)

Donadio, S.

2007-09-01

The increasing complexity of hardware features incorporated in modern processors makes high performance code generation very challenging. Library generators such as ATLAS, FFTW and SPIRAL overcome this issue by empirically searching in the space of possible program versions for the one that performs the best. This thesis explores fully automatic solution to adapt a compute-intensive application to the target architecture. By mimicking complex sequences of transformations useful to optimize real codes, we show that generative programming is a practical tool to implement a new hierarchical compilation approach for the generation of high performance code relying on the use of state-of-the-art compilers. As opposed to ATLAS, this approach is not application-dependant but can be applied to fairly generic loop structures. Our approach relies on the decomposition of the original loop nest into simpler kernels. These kernels are much simpler to optimize and furthermore, using such codes makes the performance trade off problem much simpler to express and to solve. Finally, we propose a new approach for the generation of performance libraries based on this decomposition method. We show that our method generates high-performance libraries, in particular for BLAS. (author)

Quality assurance plan, Westinghouse Water Reactor Divisions

Energy Technology Data Exchange (ETDEWEB)

1976-03-01

The Quality Assurance Program used by Westinghouse Nuclear Energy Systems Water Reactor Divisions is described. The purpose of the program is to assure that the design, materials, and workmanship on Nuclear Steam Supply System (NSSS) equipment meet applicable safety requirements, fulfill the requirements of the contracts with the applicants, and satisfy the applicable codes, standards, and regulatory requirements.

Novel anti-jamming technique for OCDMA network through FWM in SOA based wavelength converter

Science.gov (United States)

Jyoti, Vishav; Kaler, R. S.

2013-06-01

In this paper, we propose a novel anti-jamming technique for optical code division multiple access (OCDMA) network through four wave mixing (FWM) in semiconductor optical amplifier (SOA) based wavelength converter. OCDMA signal can be easily jammed with high power jamming signal. It is shown that wavelength conversion through four wave mixing in SOA has improved capability of jamming resistance. It is observed that jammer has no effect on OCDMA network even at high jamming powers by using the proposed technique.

Efficient data management techniques implemented in the Karlsruhe Monte Carlo code KAMCCO

International Nuclear Information System (INIS)

Arnecke, G.; Borgwaldt, H.; Brandl, V.; Lalovic, M.

1974-01-01

The Karlsruhe Monte Carlo Code KAMCCO is a forward neutron transport code with an eigenfunction and a fixed source option, including time-dependence. A continuous energy model is combined with a detailed representation of neutron cross sections, based on linear interpolation, Breit-Wigner resonances and probability tables. All input is processed into densely packed, dynamically addressed parameter fields and networks of pointers (addresses). Estimation routines are decoupled from random walk and analyze a storage region with sample records. This technique leads to fast execution with moderate storage requirements and without any I/O-operations except in the input and output stages. 7 references. (U.S.)

A mean field theory of coded CDMA systems

International Nuclear Information System (INIS)

Yano, Toru; Tanaka, Toshiyuki; Saad, David

2008-01-01

We present a mean field theory of code-division multiple-access (CDMA) systems with error-control coding. On the basis of the relation between the free energy and mutual information, we obtain an analytical expression of the maximum spectral efficiency of the coded CDMA system, from which a mean-field description of the coded CDMA system is provided in terms of a bank of scalar Gaussian channels whose variances in general vary at different code symbol positions. Regular low-density parity-check (LDPC)-coded CDMA systems are also discussed as an example of the coded CDMA systems

A mean field theory of coded CDMA systems

Energy Technology Data Exchange (ETDEWEB)

Yano, Toru [Graduate School of Science and Technology, Keio University, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa 223-8522 (Japan); Tanaka, Toshiyuki [Graduate School of Informatics, Kyoto University, Yoshida Hon-machi, Sakyo-ku, Kyoto-shi, Kyoto 606-8501 (Japan); Saad, David [Neural Computing Research Group, Aston University, Birmingham B4 7ET (United Kingdom)], E-mail: yano@thx.appi.keio.ac.jp

2008-08-15

We present a mean field theory of code-division multiple-access (CDMA) systems with error-control coding. On the basis of the relation between the free energy and mutual information, we obtain an analytical expression of the maximum spectral efficiency of the coded CDMA system, from which a mean-field description of the coded CDMA system is provided in terms of a bank of scalar Gaussian channels whose variances in general vary at different code symbol positions. Regular low-density parity-check (LDPC)-coded CDMA systems are also discussed as an example of the coded CDMA systems.

Energy meshing techniques for processing ENDF/B-VI cross sections using the AMPX code system

International Nuclear Information System (INIS)

Dunn, M.E.; Greene, N.M.; Leal, L.C.

1999-01-01

Modern techniques for the establishment of criticality safety for fissile systems invariably require the use of neutronic transport codes with applicable cross-section data. Accurate cross-section data are essential for solving the Boltzmann Transport Equation for fissile systems. In the absence of applicable critical experimental data, the use of independent calculational methods is crucial for the establishment of subcritical limits. Moreover, there are various independent modern transport codes available to the criticality safety analyst (e.g., KENO V.a., MCNP, and MONK). In contrast, there is currently only one complete software package that processes data from the Version 6 format of the Evaluated Nuclear Data File (ENDF) to a format useable by criticality safety codes. To facilitate independent cross-section processing, Oak Ridge National Laboratory (ORNL) is upgrading the AMPX code system to enable independent processing of Version 6 formats using state-of-the-art procedures. The AMPX code system has been in continuous use at ORNL since the early 1970s and is the premier processor for providing multigroup cross sections for criticality safety analysis codes. Within the AMPX system, the module POLIDENT is used to access the resonance parameters in File 2 of an ENDF/B library, generate point cross-section data, and combine the cross sections with File 3 point data. At the heart of any point cross-section processing code is the generation of a suitable energy mesh for representing the data. The purpose of this work is to facilitate the AMPX upgrade through the development of a new and innovative energy meshing technique for processing point cross-section data

Experimental Facilities Division/User Program Division technical progress report 1999-2000

International Nuclear Information System (INIS)

2001-01-01

In October 1999, the two divisions of the Advanced Photon Source (APS), the Accelerator Systems Division (ASD) and the Experimental Facilities Division (XFD), were reorganized into four divisions (see high-level APS organizational chart, Fig. 1.1). In addition to ASD and XFD, two new divisions were created, the APS Operations Division (AOD), to oversee APS operations, and the User Program Division (UPD), to serve the APS user community by developing and maintaining the highest quality user technical and administration support. Previous XFD Progress Reports (ANL/APS/TB-30 and ANL/APS/TB-34) covered a much broader base, including APS user administrative support and what was previously XFD operations (front ends, interlocks, etc.) This Progress Report summarizes the main scientific and technical activities of XFD, and the technical support, research and development (R and D) activities of UPD from October 1998 through November 2000. The report is divided into four major sections, (1) Introduction, (2) SRI-CAT Beamlines, Technical Developments, and Scientific Applications, (3) User Technical Support, and (4) Major Plans for the Future. Sections 2 and 3 describe the technical activities and research accomplishments of the XFD and UPD personnel in supporting the synchrotron radiation instrumentation (SRI) collaborative access team (CAT) and the general APS user community. Also included in this report is a comprehensive list of publications (Appendix 1) and presentations (Appendix 2) by XFD and UPD staff during the time period covered by this report. The organization of section 2, SRI CAT Beamlines, Technical Developments, and Scientific Applications has been made along scientific techniques/disciplines and not ''geographical'' boundaries of the sectors in which the work was performed. Therefore items under the subsection X-ray Imaging and Microfocusing could have been (and were) performed on several different beamlines by staff in different divisions. The management of

Statistical physics inspired energy-efficient coded-modulation for optical communications.

Science.gov (United States)

Djordjevic, Ivan B; Xu, Lei; Wang, Ting

2012-04-15

Because Shannon's entropy can be obtained by Stirling's approximation of thermodynamics entropy, the statistical physics energy minimization methods are directly applicable to the signal constellation design. We demonstrate that statistical physics inspired energy-efficient (EE) signal constellation designs, in combination with large-girth low-density parity-check (LDPC) codes, significantly outperform conventional LDPC-coded polarization-division multiplexed quadrature amplitude modulation schemes. We also describe an EE signal constellation design algorithm. Finally, we propose the discrete-time implementation of D-dimensional transceiver and corresponding EE polarization-division multiplexed system. © 2012 Optical Society of America

Seroprevalence of hepatitis C in pregnant females of Hazara division

International Nuclear Information System (INIS)

Gul, N.; Idris, M.; Sarwar, J.; Suleman, M.

2009-01-01

Hepatitis C Virus (HCV), the causative agent of Hepatitis C is prevalent in different countries including Pakistan. Studies have been conducted on various aspects of HCV in Pakistan. The present study was planed to see the prevalence of hepatitis C in pregnant females of Hazara Division. Five hundred pregnant females of reproductive age group from Hazara Division selected by non probability convenient sampling technique were studied from 1, March 2006 to 28, February 2007 at Ayub Teaching Hospital, and District Head quarter Hospitals Abbottabad, Haripur and Mansehra. After initial serving by immunology technique positive cases were confirmed by Enzyme Linked Immunosorbent Essay (ELISA). Seroprevalence of HCV in pregnant females of Hazara division was 8.9%. Females aged from 25-35 constituted the largest group among positive cases. HCV was more prevalent in District Abbottabad as compared to the other districts of Hazara division. Seroprevalence of HCV in pregnant females of Hazara Division is different from the figures already reported form the other parts of Pakistan. (author)

Iterated decoding of modified product codes in optical networks

DEFF Research Database (Denmark)

Justesen, Jørn

2009-01-01

Appendix I of the standard ITU-T G.975 contains several codes that have been proposed for improved performance of optical transmission. While the original application was submarine cables, the codes are now also used in terrestrial systems where wavelength-division multiplexing (WDM) is introduced...

Design and simulations of a spectral efficient optical code division multiple access scheme using alternated energy differentiation and single-user soft-decision demodulation

Science.gov (United States)

A. Garba, Aminata

2017-01-01

This paper presents a new approach to optical Code Division Multiple Access (CDMA) network transmission scheme using alternated amplitude sequences and energy differentiation at the transmitters to allow concurrent and secure transmission of several signals. The proposed system uses error control encoding and soft-decision demodulation to reduce the multi-user interference at the receivers. The design of the proposed alternated amplitude sequences, the OCDMA energy modulators and the soft decision, single-user demodulators are also presented. Simulation results show that the proposed scheme allows achieving spectral efficiencies higher than several reported results for optical CDMA and much higher than the Gaussian CDMA capacity limit.

Parallel optoelectronic trinary signed-digit division

Science.gov (United States)

Alam, Mohammad S.

1999-03-01

The trinary signed-digit (TSD) number system has been found to be very useful for parallel addition and subtraction of any arbitrary length operands in constant time. Using the TSD addition and multiplication modules as the basic building blocks, we develop an efficient algorithm for performing parallel TSD division in constant time. The proposed division technique uses one TSD subtraction and two TSD multiplication steps. An optoelectronic correlator based architecture is suggested for implementation of the proposed TSD division algorithm, which fully exploits the parallelism and high processing speed of optics. An efficient spatial encoding scheme is used to ensure better utilization of space bandwidth product of the spatial light modulators used in the optoelectronic implementation.

Wavelength-Hopping Time-Spreading Optical CDMA With Bipolar Codes

Science.gov (United States)

Kwong, Wing C.; Yang, Guu-Chang; Chang, Cheng-Yuan

2005-01-01

Two-dimensional wavelength-hopping time-spreading coding schemes have been studied recently for supporting greater numbers of subscribers and simultaneous users than conventional one-dimensional approaches in optical code-division multiple-access (OCDMA) systems. To further improve both numbers without sacrificing performance, a new code design utilizing bipolar codes for both wavelength hopping and time spreading is studied and analyzed in this paper. A rapidly programmable, integratable hardware design for this new coding scheme, based on arrayed-waveguide gratings, is also discussed.

Quantum BCH Codes Based on Spectral Techniques

International Nuclear Information System (INIS)

Guo Ying; Zeng Guihua

2006-01-01

When the time variable in quantum signal processing is discrete, the Fourier transform exists on the vector space of n-tuples over the Galois field F 2 , which plays an important role in the investigation of quantum signals. By using Fourier transforms, the idea of quantum coding theory can be described in a setting that is much different from that seen that far. Quantum BCH codes can be defined as codes whose quantum states have certain specified consecutive spectral components equal to zero and the error-correcting ability is also described by the number of the consecutive zeros. Moreover, the decoding of quantum codes can be described spectrally with more efficiency.

A Teacher’s Experience in Teaching with Student Teams-Achievement Division (STAD Technique

Directory of Open Access Journals (Sweden)

Yuliana Natsir

2015-07-01

Full Text Available This study looks at Student Teams-Achievement Division (STAD implementation from a qualitative approach by observing and interviewing a teacher who successfully improved his EFL students’ reading achievement with this technique. The procedures by Shaaban and Ghaith (2005 were the foundation for STAD implementation, and an interview was done to exhibit the teacher’s stance on the use of STAD. Based on our observation during his teaching in a reading class by implementing STAD, it was found that he did not implement one procedure of this technique, which was assigning a role for each member of the groups. From the interview, he informed that he did not conduct this procedure because he believed that assigning roles should be entrusted to the students to increase their sense of responsibility towards the accomplishment of the group task. Furthermore, he also modified five procedures from nine procedures of STAD proposed by Shaaban and Ghaith (2005. The modified procedures were related to the way the quiz was given to students, providing printed answer key, ways of correcting the student’s quiz, providing the team recognition form, and ways of recognizing the students’ achievement. He informed that they were modified due to the efficacy of students, time limitation and the school’s financial problem.

LDPC coded OFDM over the atmospheric turbulence channel.

Science.gov (United States)

Djordjevic, Ivan B; Vasic, Bane; Neifeld, Mark A

2007-05-14

Low-density parity-check (LDPC) coded optical orthogonal frequency division multiplexing (OFDM) is shown to significantly outperform LDPC coded on-off keying (OOK) over the atmospheric turbulence channel in terms of both coding gain and spectral efficiency. In the regime of strong turbulence at a bit-error rate of 10(-5), the coding gain improvement of the LDPC coded single-side band unclipped-OFDM system with 64 sub-carriers is larger than the coding gain of the LDPC coded OOK system by 20.2 dB for quadrature-phase-shift keying (QPSK) and by 23.4 dB for binary-phase-shift keying (BPSK).

High performance optical encryption based on computational ghost imaging with QR code and compressive sensing technique

Science.gov (United States)

Zhao, Shengmei; Wang, Le; Liang, Wenqiang; Cheng, Weiwen; Gong, Longyan

2015-10-01

In this paper, we propose a high performance optical encryption (OE) scheme based on computational ghost imaging (GI) with QR code and compressive sensing (CS) technique, named QR-CGI-OE scheme. N random phase screens, generated by Alice, is a secret key and be shared with its authorized user, Bob. The information is first encoded by Alice with QR code, and the QR-coded image is then encrypted with the aid of computational ghost imaging optical system. Here, measurement results from the GI optical system's bucket detector are the encrypted information and be transmitted to Bob. With the key, Bob decrypts the encrypted information to obtain the QR-coded image with GI and CS techniques, and further recovers the information by QR decoding. The experimental and numerical simulated results show that the authorized users can recover completely the original image, whereas the eavesdroppers can not acquire any information about the image even the eavesdropping ratio (ER) is up to 60% at the given measurement times. For the proposed scheme, the number of bits sent from Alice to Bob are reduced considerably and the robustness is enhanced significantly. Meantime, the measurement times in GI system is reduced and the quality of the reconstructed QR-coded image is improved.

Japan Atomic Energy Research Institute, Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1979-09-01

Research activities in the Division of Reactor Engineering in fiscal 1978 are described. Works of the Division are development of multi-purpose Very High Temperature Gas Cooled Reactor, fusion reactor engineering, and development of Liquid Metal Fast Breeder Reactor for Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, dynamics analysis and control method development, fusion reactor technology, and Committees on Reactor Physics and in Decommissioning of Nuclear Facilities. (author)

Materials division facilities and equipment

International Nuclear Information System (INIS)

Biest, O. v.d.

1984-01-01

The research activities of the Division at the Petten Establishment have the aims of characterising the properties of high temperature materials in industrial process environments and of understanding the structures involved in order to gain an insight into behavioural mechanisms. Metallic materials fall within the scope of the programme; the activities are, at present, almost entirely concerned with austenitic steels and nickel based alloys. Starting in 1984, advanced ceramic materials will be studied as well. The equipment available permits the study of mechanical properties in controlled gaseous environments, of the rates and mechanisms of corrosive reactions between materials and those environments, and of the surface and bulk structures by advanced physical techniques. Special preparation and treatment techniques are available. The Division has developed a Data Bank on high temperature alloys. It also operates an information Centre, the activities of which include the organisation of scientific meetings, the commissioning of ''state of the art'' studies on topics in the field of high temperature materials and their applications and the development of a inventory of current research activities in the field in Europe. This booklet is intended to present the facilities and services of the Division to the organizations which are interested in its programmes of work

Code-division multiple-access protocol for active RFID systems

Science.gov (United States)

Mazurek, Gustaw; Szabatin, Jerzy

2008-01-01

Most of the Radio Frequency Identification (RFID) systems operating in HF and UHF bands employ narrowband modulations (FSK or ASK) with Manchester coding. However, these simple transmission schemes are vulnerable to narrowband interference (NBI) generated by other radio systems working in the same frequency band, and also suffer from collision problem and need special anti-collision procedures. This becomes especially important when operating in a noisy, crowded industrial environment. In this paper we show the performance of RFID system with DS-CDMA transmission in comparison to a standard system with FSK modulation defined in ISO 18000-7. Our simulation results show that without any bandwidth expansion the immunity against NBI can be improved by 8 dB and the system capacity can be 7 times higher when using DS-CDMA transmission instead of FSK modulation with Manchester coding.

Uniform Circular Antenna Array Applications in Coded DS-CDMA Mobile Communication Systems

National Research Council Canada - National Science Library

Seow, Tian

2003-01-01

...) has greatly increased. This thesis examines the use of an equally spaced circular adaptive antenna array at the mobile station for a typical coded direct sequence code division multiple access (DS-CDMA...

Fixed capacity and variable member grouping assignment of orthogonal variable spreading factor code tree for code division multiple access networks

Directory of Open Access Journals (Sweden)

Vipin Balyan

2014-08-01

Full Text Available Orthogonal variable spreading factor codes are used in the downlink to maintain the orthogonality between different channels and are used to handle new calls arriving in the system. A period of operation leads to fragmentation of vacant codes. This leads to code blocking problem. The assignment scheme proposed in this paper is not affected by fragmentation, as the fragmentation is generated by the scheme itself. In this scheme, the code tree is divided into groups whose capacity is fixed and numbers of members (codes are variable. A group with maximum number of busy members is used for assignment, this leads to fragmentation of busy groups around code tree and compactness within group. The proposed scheme is well evaluated and compared with other schemes using parameters like code blocking probability and call establishment delay. Through simulations it has been demonstrated that the proposed scheme not only adequately reduces code blocking probability, but also requires significantly less time before assignment to locate a vacant code for assignment, which makes it suitable for the real-time calls.

Division of Radiological Protection : progress report, 1989-1991

International Nuclear Information System (INIS)

Gupta, B.L.; Nagarajan, P.S.; Bhatt, B.C.; Seethapathy, A.; Pradhan, A.S.; Vishwakarma, R.R.

1992-01-01

This report describes the work of the Division of Radiological Protection during 1989-91, for implementation of radiation safety in all institutions in the country using radiation sources for medical, industrial and research applications. It gives information about personnel monitoring using photographic film and TLD badges, neutron monitoring badges, dosimetric techniques developed, calibration techniques for high-dose irradiators, design and fabrication of special radiation protection instruments, advisory and licensing services, regulation and transport of radioactive materials, periodic protection survey, education and training related to radiation safety programmes. About 164 publications by the staff of this Division are listed. (author). 1 index., 1 tab

New hybrid technique for impulsive noise suppression in OFDM systems

International Nuclear Information System (INIS)

Mirza, A.; Zeb, A.; Sheikh, S.A.

2017-01-01

In this paper, a new hybrid technique employing RS (Reed Solomon) coding and adaptive filter for impulsive noise suppression in OFDM (Orthogonal Frequency Division Multiplexing) systems is presented. Adaptive filter creates a more accurate estimate of the original OFDM signal after impulsive noise cancellation. The residual impulsive noise is further mitigated by RS decoder in the second stage of proposed technique. Three members of adaptive filters family i.e. NLMS (Normalized Least Mean Square) algorithm, RLS (Recursive Least Square) algorithm and Bhagyashri algorithm are tested with RS decoder in the proposed hybrid technique. Furthermore, the results in terms of steady state MSE (Mean Square Error) reduction, BER (Bit Error Rate) improvement and SNR (Signal to Noise Ratio) enhancement confirm the effectiveness of the proposed dual faceted technique when compared with the recently reported techniques in literature. (author)

Design of variable-weight quadratic congruence code for optical CDMA

Science.gov (United States)

Feng, Gang; Cheng, Wen-Qing; Chen, Fu-Jun

2015-09-01

A variable-weight code family referred to as variable-weight quadratic congruence code (VWQCC) is constructed by algebraic transformation for incoherent synchronous optical code division multiple access (OCDMA) systems. Compared with quadratic congruence code (QCC), VWQCC doubles the code cardinality and provides the multiple code-sets with variable code-weight. Moreover, the bit-error rate (BER) performance of VWQCC is superior to those of conventional variable-weight codes by removing or padding pulses under the same chip power assumption. The experiment results show that VWQCC can be well applied to the OCDMA with quality of service (QoS) requirements.

A Unified Framework of the Performance Evaluation of Optical Time-Wavelength Code-Division Multiple-Access Systems

Science.gov (United States)

Inaty, Elie

In this paper, we provide an analysis to the performance of optical time-wavelength code-division multiple-access (OTW-CDMA) network when the system is working above the nominal transmission rate limit imposed by the passive encoding-decoding operation. We address the problem of overlapping in such a system and how it can directly affect the bit error rate (BER). A unified mathematical framework is presented under the assumption of one coincidence sequences with non-repeating wavelengths. A closed form expression of the multiple access interference limited BER is provided as a function of different system parameters. Results show that the performance of OTW-CDMA system may be critically affected when working above the nominal limit; an event that may happen when the network operates at high transmission rate. In addition, the impact of the derived error probability on the performance of two newly proposed MAC protocols, the S-ALOHA and the R3T, is also investigated. It is shown that for low transmission rates, the S-ALOHA is better than the R3T; while the R3T is better at very high transmission rates. However, in general it is postulated that the R3T protocol suffers a higher delay mainly because of the presence of additional modes.

Coordination analysis of players' distribution in football using cross-correlation and vector coding techniques.

Science.gov (United States)

Moura, Felipe Arruda; van Emmerik, Richard E A; Santana, Juliana Exel; Martins, Luiz Eduardo Barreto; Barros, Ricardo Machado Leite de; Cunha, Sergio Augusto

2016-12-01

The purpose of this study was to investigate the coordination between teams spread during football matches using cross-correlation and vector coding techniques. Using a video-based tracking system, we obtained the trajectories of 257 players during 10 matches. Team spread was calculated as functions of time. For a general coordination description, we calculated the cross-correlation between the signals. Vector coding was used to identify the coordination patterns between teams during offensive sequences that ended in shots on goal or defensive tackles. Cross-correlation showed that opponent teams have a tendency to present in-phase coordination, with a short time lag. During offensive sequences, vector coding results showed that, although in-phase coordination dominated, other patterns were observed. We verified that during the early stages, offensive sequences ending in shots on goal present greater anti-phase and attacking team phase periods, compared to sequences ending in tackles. Results suggest that the attacking team may seek to present a contrary behaviour of its opponent (or may lead the adversary behaviour) in the beginning of the attacking play, regarding to the distribution strategy, to increase the chances of a shot on goal. The techniques allowed detecting the coordination patterns between teams, providing additional information about football dynamics and players' interaction.

Technique Triangulation for Validation in Directed Content Analysis

Directory of Open Access Journals (Sweden)

Áine M. Humble PhD

2009-09-01

Full Text Available Division of labor in wedding planning varies for first-time marriages, with three types of couples—traditional, transitional, and egalitarian—identified, but nothing is known about wedding planning for remarrying individuals. Using semistructured interviews, the author interviewed 14 couples in which at least one person had remarried and used directed content analysis to investigate the extent to which the aforementioned typology could be transferred to this different context. In this paper she describes how a triangulation of analytic techniques provided validation for couple classifications and also helped with moving beyond “blind spots” in data analysis. Analytic approaches were the constant comparative technique, rank order comparison, and visual representation of coding, using MAXQDA 2007's tool called TextPortraits.

Identification of Sparse Audio Tampering Using Distributed Source Coding and Compressive Sensing Techniques

Directory of Open Access Journals (Sweden)

Valenzise G

2009-01-01

Full Text Available In the past few years, a large amount of techniques have been proposed to identify whether a multimedia content has been illegally tampered or not. Nevertheless, very few efforts have been devoted to identifying which kind of attack has been carried out, especially due to the large data required for this task. We propose a novel hashing scheme which exploits the paradigms of compressive sensing and distributed source coding to generate a compact hash signature, and we apply it to the case of audio content protection. The audio content provider produces a small hash signature by computing a limited number of random projections of a perceptual, time-frequency representation of the original audio stream; the audio hash is given by the syndrome bits of an LDPC code applied to the projections. At the content user side, the hash is decoded using distributed source coding tools. If the tampering is sparsifiable or compressible in some orthonormal basis or redundant dictionary, it is possible to identify the time-frequency position of the attack, with a hash size as small as 200 bits/second; the bit saving obtained by introducing distributed source coding ranges between 20% to 70%.

Spectroscopy Division progress report for Jan 1983 - Dec 1984

International Nuclear Information System (INIS)

Dixit, R.M.

1985-01-01

The Research and Development (R and D) activities of the Spectroscopy Division of the Bhabha Atomic Research Centre, Bombay, during the period from January 1983 to December 1984 are reported. The main thrust of the activities of the Division is directed towards meeting the spectrochemical analytical requirements of the nuclear energy programmes and the related R and D projects of the Department of Atomic Energy. These activities are described in the form of summaries grouped under the headings:(1) analyses by optical emission, X-ray fluorescence, X-ray excited optical luminescence and other techniques, (2) atomic, molecular and solid state spectroscopy, (3) optics and thin films, and (4) electronic instrumentation. Two feature articles which are included in the report bring out the salient features of X-ray absorption fine structure spectroscopy (EXFAS) and laser spectroscopic techniques for trace analysis and describe the Division's efforts in setting up facilities to carry out work in these emerging fields. Other activities of the Division are teaching trainees and guiding research leading to M.Sc. and Ph.D. degrees. A list of papers published in journals and papers presented at conferences, symposia etc. by the staff-members of the Division is given. A divisional staff chart is also given. (M.G.B.)

Japan Atomic Energy Research Institute, Reactor Engineering Division annual report

International Nuclear Information System (INIS)

1981-09-01

Research activities in the Division of Reactor Engineering in fiscal 1980 are described. The work of the Division is closely related to development of multipurpose Very High Temperature Gas Cooled Reactor and fusion reactor, and development of Liquid Metal Fast Breeder Reactor carried out by Power Reactor and Nuclear Fuel Development Corporation. Contents of the report are achievements in fields such as nuclear data and group constants, theoretical method and code development, integral experiment and analysis, shielding, reactor and nuclear instrumentation, reactor control and diagnosis, and fusion reactor technology, and activities of the Committee on Reactor Physics. (author)

Instanton-based techniques for analysis and reduction of error floors of LDPC codes

International Nuclear Information System (INIS)

Chertkov, Michael; Chilappagari, Shashi K.; Stepanov, Mikhail G.; Vasic, Bane

2008-01-01

We describe a family of instanton-based optimization methods developed recently for the analysis of the error floors of low-density parity-check (LDPC) codes. Instantons are the most probable configurations of the channel noise which result in decoding failures. We show that the general idea and the respective optimization technique are applicable broadly to a variety of channels, discrete or continuous, and variety of sub-optimal decoders. Specifically, we consider: iterative belief propagation (BP) decoders, Gallager type decoders, and linear programming (LP) decoders performing over the additive white Gaussian noise channel (AWGNC) and the binary symmetric channel (BSC). The instanton analysis suggests that the underlying topological structures of the most probable instanton of the same code but different channels and decoders are related to each other. Armed with this understanding of the graphical structure of the instanton and its relation to the decoding failures, we suggest a method to construct codes whose Tanner graphs are free of these structures, and thus have less significant error floors.

Instanton-based techniques for analysis and reduction of error floor of LDPC codes

Energy Technology Data Exchange (ETDEWEB)

Chertkov, Michael [Los Alamos National Laboratory; Chilappagari, Shashi K [Los Alamos National Laboratory; Stepanov, Mikhail G [Los Alamos National Laboratory; Vasic, Bane [SENIOR MEMBER, IEEE

2008-01-01

We describe a family of instanton-based optimization methods developed recently for the analysis of the error floors of low-density parity-check (LDPC) codes. Instantons are the most probable configurations of the channel noise which result in decoding failures. We show that the general idea and the respective optimization technique are applicable broadly to a variety of channels, discrete or continuous, and variety of sub-optimal decoders. Specifically, we consider: iterative belief propagation (BP) decoders, Gallager type decoders, and linear programming (LP) decoders performing over the additive white Gaussian noise channel (AWGNC) and the binary symmetric channel (BSC). The instanton analysis suggests that the underlying topological structures of the most probable instanton of the same code but different channels and decoders are related to each other. Armed with this understanding of the graphical structure of the instanton and its relation to the decoding failures, we suggest a method to construct codes whose Tanner graphs are free of these structures, and thus have less significant error floors.

The effect of structural design parameters on FPGA-based feed-forward space-time trellis coding-orthogonal frequency division multiplexing channel encoders

Science.gov (United States)

Passas, Georgios; Freear, Steven; Fawcett, Darren

2010-08-01

Orthogonal frequency division multiplexing (OFDM)-based feed-forward space-time trellis code (FFSTTC) encoders can be synthesised as very high speed integrated circuit hardware description language (VHDL) designs. Evaluation of their FPGA implementation can lead to conclusions that help a designer to decide the optimum implementation, given the encoder structural parameters. VLSI architectures based on 1-bit multipliers and look-up tables (LUTs) are compared in terms of FPGA slices and block RAMs (area), as well as in terms of minimum clock period (speed). Area and speed graphs versus encoder memory order are provided for quadrature phase shift keying (QPSK) and 8 phase shift keying (8-PSK) modulation and two transmit antennas, revealing best implementation under these conditions. The effect of number of modulation bits and transmit antennas on the encoder implementation complexity is also investigated.

Development of a fuel depletion sensitivity calculation module for multi-cell problems in a deterministic reactor physics code system CBZ

International Nuclear Information System (INIS)

Chiba, Go; Kawamoto, Yosuke; Narabayashi, Tadashi

2016-01-01

Highlights: • A new functionality of fuel depletion sensitivity calculations is developed in a code system CBZ. • This is based on the generalized perturbation theory for fuel depletion problems. • The theory with a multi-layer depletion step division scheme is described. • Numerical techniques employed in actual implementation are also provided. - Abstract: A new functionality of fuel depletion sensitivity calculations is developed as one module in a deterministic reactor physics code system CBZ. This is based on the generalized perturbation theory for fuel depletion problems. The theory for fuel depletion problems with a multi-layer depletion step division scheme is described in detail. Numerical techniques employed in actual implementation are also provided. Verification calculations are carried out for a 3 × 3 multi-cell problem consisting of two different types of fuel pins. It is shown that the sensitivities of nuclide number densities after fuel depletion with respect to the nuclear data calculated by the new module agree well with reference sensitivities calculated by direct numerical differentiation. To demonstrate the usefulness of the new module, fuel depletion sensitivities in different multi-cell arrangements are compared and non-negligible differences are observed. Nuclear data-induced uncertainties of nuclide number densities obtained with the calculated sensitivities are also compared.

Joint power control based on service factor for code division multiple access system%TDD-CDMA系统中基于业务统计的联合功率控制算法

Institute of Scientific and Technical Information of China (English)

陈波; 戎蒙恬; 胡威

2008-01-01

An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex (TDD)-code division multiple access (CDMA) systems are analyzed. A joint power control algorithm based on service factor is presented to address the TDD-CDMA mobile services in the burst mode according to the Markov modulated Bernoulli process. The joint power control equation is derived. A function model is developed to verify the new algorithm and evaluate its performance. Simulation results show that the new power control algorithm can estimate interference strength more precisely, speed up convergence of power control, and enhance power efficiency and system capacity. It is shown that the proposed algorithm is more robust against rink gain changes, and outperforms the reference algorithms.

Performance Analysis of a De-correlated Modified Code Tracking Loop for Synchronous DS-CDMA System under Multiuser Environment

Science.gov (United States)

Wu, Ya-Ting; Wong, Wai-Ki; Leung, Shu-Hung; Zhu, Yue-Sheng

This paper presents the performance analysis of a De-correlated Modified Code Tracking Loop (D-MCTL) for synchronous direct-sequence code-division multiple-access (DS-CDMA) systems under multiuser environment. Previous studies have shown that the imbalance of multiple access interference (MAI) in the time lead and time lag portions of the signal causes tracking bias or instability problem in the traditional correlating tracking loop like delay lock loop (DLL) or modified code tracking loop (MCTL). In this paper, we exploit the de-correlating technique to combat the MAI at the on-time code position of the MCTL. Unlike applying the same technique to DLL which requires an extensive search algorithm to compensate the noise imbalance which may introduce small tracking bias under low signal-to-noise ratio (SNR), the proposed D-MCTL has much lower computational complexity and exhibits zero tracking bias for the whole range of SNR, regardless of the number of interfering users. Furthermore, performance analysis and simulations based on Gold codes show that the proposed scheme has better mean square tracking error, mean-time-to-lose-lock and near-far resistance than the other tracking schemes, including traditional DLL (T-DLL), traditional MCTL (T-MCTL) and modified de-correlated DLL (MD-DLL).

High performance mixed optical CDMA system using ZCC code and multiband OFDM

Directory of Open Access Journals (Sweden)

Nawawi N. M.

2017-01-01

Full Text Available In this paper, we have proposed a high performance network design, which is based on mixed optical Code Division Multiple Access (CDMA system using Zero Cross Correlation (ZCC code and multiband Orthogonal Frequency Division Multiplexing (OFDM called catenated OFDM. In addition, we also investigate the related changing parameters such as; effective power, number of user, number of band, code length and code weight. Then we theoretically analyzed the system performance comprehensively while considering up to five OFDM bands. The feasibility of the proposed system architecture is verified via the numerical analysis. The research results demonstrated that our developed modulation solution can significantly enhanced the total number of user; improving up to 80% for five catenated bands compared to traditional optical CDMA system, with the code length equals to 80, transmitted at 622 Mbps. It is also demonstrated that the BER performance strongly depends on number of weight, especially with less number of users. As the number of weight increases, the BER performance is better.

High performance mixed optical CDMA system using ZCC code and multiband OFDM

Science.gov (United States)

Nawawi, N. M.; Anuar, M. S.; Junita, M. N.; Rashidi, C. B. M.

2017-11-01

In this paper, we have proposed a high performance network design, which is based on mixed optical Code Division Multiple Access (CDMA) system using Zero Cross Correlation (ZCC) code and multiband Orthogonal Frequency Division Multiplexing (OFDM) called catenated OFDM. In addition, we also investigate the related changing parameters such as; effective power, number of user, number of band, code length and code weight. Then we theoretically analyzed the system performance comprehensively while considering up to five OFDM bands. The feasibility of the proposed system architecture is verified via the numerical analysis. The research results demonstrated that our developed modulation solution can significantly enhanced the total number of user; improving up to 80% for five catenated bands compared to traditional optical CDMA system, with the code length equals to 80, transmitted at 622 Mbps. It is also demonstrated that the BER performance strongly depends on number of weight, especially with less number of users. As the number of weight increases, the BER performance is better.

Error-correction coding for digital communications

Science.gov (United States)

Clark, G. C., Jr.; Cain, J. B.

This book is written for the design engineer who must build the coding and decoding equipment and for the communication system engineer who must incorporate this equipment into a system. It is also suitable as a senior-level or first-year graduate text for an introductory one-semester course in coding theory. Fundamental concepts of coding are discussed along with group codes, taking into account basic principles, practical constraints, performance computations, coding bounds, generalized parity check codes, polynomial codes, and important classes of group codes. Other topics explored are related to simple nonalgebraic decoding techniques for group codes, soft decision decoding of block codes, algebraic techniques for multiple error correction, the convolutional code structure and Viterbi decoding, syndrome decoding techniques, and sequential decoding techniques. System applications are also considered, giving attention to concatenated codes, coding for the white Gaussian noise channel, interleaver structures for coded systems, and coding for burst noise channels.

Performance of Different OCDMA Codes with FWM and XPM Nonlinear Effects

Science.gov (United States)

Rana, Shivani; Gupta, Amit

2017-08-01

In this paper, 1 Gb/s non-linear optical code division multiple access system have been simulated and modeled. To reduce multiple user interference multi-diagonal (MD) code which possesses the property of having zero cross-correlation have been deployed. The MD code shows better results than Walsh-Hadamard and multi-weight code under the nonlinear effect of four-wave mixing (FWM) and cross-phase modulation (XPM). The simulation results reveal that effect of FWM reduces when MD codes are employed as compared to other codes.

Automated importance generation and biasing techniques for Monte Carlo shielding techniques by the TRIPOLI-3 code

International Nuclear Information System (INIS)

Both, J.P.; Nimal, J.C.; Vergnaud, T.

1990-01-01

We discuss an automated biasing procedure for generating the parameters necessary to achieve efficient Monte Carlo biasing shielding calculations. The biasing techniques considered here are exponential transform and collision biasing deriving from the concept of the biased game based on the importance function. We use a simple model of the importance function with exponential attenuation as the distance to the detector increases. This importance function is generated on a three-dimensional mesh including geometry and with graph theory algorithms. This scheme is currently being implemented in the third version of the neutron and gamma ray transport code TRIPOLI-3. (author)

Survey of nuclear fuel-cycle codes

International Nuclear Information System (INIS)

Thomas, C.R.; de Saussure, G.; Marable, J.H.

1981-04-01

A two-month survey of nuclear fuel-cycle models was undertaken. This report presents the information forthcoming from the survey. Of the nearly thirty codes reviewed in the survey, fifteen of these codes have been identified as potentially useful in fulfilling the tasks of the Nuclear Energy Analysis Division (NEAD) as defined in their FY 1981-1982 Program Plan. Six of the fifteen codes are given individual reviews. The individual reviews address such items as the funding agency, the author and organization, the date of completion of the code, adequacy of documentation, computer requirements, history of use, variables that are input and forecast, type of reactors considered, part of fuel cycle modeled and scope of the code (international or domestic, long-term or short-term, regional or national). The report recommends that the Model Evaluation Team perform an evaluation of the EUREKA uranium mining and milling code

MUP, CEC-DES, STRADE. Codes for uncertainty propagation, experimental design and stratified random sampling techniques

International Nuclear Information System (INIS)

Amendola, A.; Astolfi, M.; Lisanti, B.

1983-01-01

The report describes the how-to-use of the codes: MUP (Monte Carlo Uncertainty Propagation) for uncertainty analysis by Monte Carlo simulation, including correlation analysis, extreme value identification and study of selected ranges of the variable space; CEC-DES (Central Composite Design) for building experimental matrices according to the requirements of Central Composite and Factorial Experimental Designs; and, STRADE (Stratified Random Design) for experimental designs based on the Latin Hypercube Sampling Techniques. Application fields, of the codes are probabilistic risk assessment, experimental design, sensitivity analysis and system identification problems

Rate adaptive multilevel coded modulation with high coding gain in intensity modulation direct detection optical communication

Science.gov (United States)

Xiao, Fei; Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Zhang, Qi; Tian, Qinghua; Tian, Feng; Wang, Yongjun; Rao, Lan; Ullah, Rahat; Zhao, Feng; Li, Deng'ao

2018-02-01

A rate-adaptive multilevel coded modulation (RA-MLC) scheme based on fixed code length and a corresponding decoding scheme is proposed. RA-MLC scheme combines the multilevel coded and modulation technology with the binary linear block code at the transmitter. Bits division, coding, optional interleaving, and modulation are carried out by the preset rule, then transmitted through standard single mode fiber span equal to 100 km. The receiver improves the accuracy of decoding by means of soft information passing through different layers, which enhances the performance. Simulations are carried out in an intensity modulation-direct detection optical communication system using MATLAB®. Results show that the RA-MLC scheme can achieve bit error rate of 1E-5 when optical signal-to-noise ratio is 20.7 dB. It also reduced the number of decoders by 72% and realized 22 rate adaptation without significantly increasing the computing time. The coding gain is increased by 7.3 dB at BER=1E-3.

Phase-coded multi-pulse technique for ultrasonic high-order harmonic imaging of biological tissues in vitro

International Nuclear Information System (INIS)

Ma Qingyu; Zhang Dong; Gong Xiufen; Ma Yong

2007-01-01

Second or higher order harmonic imaging shows significant improvement in image clarity but is degraded by low signal-noise ratio (SNR) compared with fundamental imaging. This paper presents a phase-coded multi-pulse technique to provide the enhancement of SNR for the desired high-order harmonic ultrasonic imaging. In this technique, with N phase-coded pulses excitation, the received Nth harmonic signal is enhanced by 20 log 10 N dB compared with that in the single-pulse mode, whereas the fundamental and other order harmonic components are efficiently suppressed to reduce image confusion. The principle of this technique is theoretically discussed based on the theory of the finite amplitude sound waves, and examined by measurements of the axial and lateral beam profiles as well as the phase shift of the harmonics. In the experimental imaging for two biological tissue specimens, a plane piston source at 2 MHz is used to transmit a sequence of multiple pulses with equidistant phase shift. The second to fifth harmonic images are obtained using this technique with N = 2 to 5, and compared with the images obtained at the fundamental frequency. Results demonstrate that this technique of relying on higher order harmonics seems to provide a better resolution and contrast of ultrasonic images

A large capacity time division multiplexed (TDM) laser beam combining technique enabled by nanosecond speed KTN deflector

Science.gov (United States)

Yin, Stuart (Shizhuo); Chao, Ju-Hung; Zhu, Wenbin; Chen, Chang-Jiang; Campbell, Adrian; Henry, Michael; Dubinskiy, Mark; Hoffman, Robert C.

2017-08-01

In this paper, we present a novel large capacity (a 1000+ channel) time division multiplexing (TDM) laser beam combining technique by harnessing a state-of-the-art nanosecond speed potassium tantalate niobate (KTN) electro-optic (EO) beam deflector as the time division multiplexer. The major advantages of TDM approach are: (1) large multiplexing capability (over 1000 channels), (2) high spatial beam quality (the combined beam has the same spatial profile as the individual beam), (3) high spectral beam quality (the combined beam has the same spectral width as the individual beam, and (4) insensitive to the phase fluctuation of individual laser because of the nature of the incoherent beam combining. The quantitative analyses show that it is possible to achieve over one hundred kW average power, single aperture, single transverse mode solid state and/or fiber laser by pursuing this innovative beam combining method, which represents a major technical advance in the field of high energy lasers. Such kind of 100+ kW average power diffraction limited beam quality lasers can play an important role in a variety of applications such as laser directed energy weapons (DEW) and large-capacity high-speed laser manufacturing, including cutting, welding, and printing.

Noncoherent Spectral Optical CDMA System Using 1D Active Weight Two-Code Keying Codes

Directory of Open Access Journals (Sweden)

Bih-Chyun Yeh

2016-01-01

Full Text Available We propose a new family of one-dimensional (1D active weight two-code keying (TCK in spectral amplitude coding (SAC optical code division multiple access (OCDMA networks. We use encoding and decoding transfer functions to operate the 1D active weight TCK. The proposed structure includes an optical line terminal (OLT and optical network units (ONUs to produce the encoding and decoding codes of the proposed OLT and ONUs, respectively. The proposed ONU uses the modified cross-correlation to remove interferences from other simultaneous users, that is, the multiuser interference (MUI. When the phase-induced intensity noise (PIIN is the most important noise, the modified cross-correlation suppresses the PIIN. In the numerical results, we find that the bit error rate (BER for the proposed system using the 1D active weight TCK codes outperforms that for two other systems using the 1D M-Seq codes and 1D balanced incomplete block design (BIBD codes. The effective source power for the proposed system can achieve −10 dBm, which has less power than that for the other systems.

Advanced Equalization Techniques for Digital Coherent Optical Receivers

DEFF Research Database (Denmark)

Arlunno, Valeria

approach based on joint encoding and equalization technique, known as Turbo Equalization (TE). This scheme is demonstrated to be powerful in transmission impairments mitigation for high order modulations formats, such as 16 Quadrature Amplitude Modulation (QAM), considered a key technology for high speed...... a lower complexity convolutional code compared to state of the art reports. Furthermore, in order to fulfill the strict constrains of spectral efficiency, this thesis shows the application of digital adaptive equalizer for reconfigurable and Ultra Dense Wavelength Division Multiplexing (U......-over-Fiber (RoF) transmission system for a stand alone case and mixed modulation mixed bit rates transmission scheme. In conclusion, this PhD thesis demonstrates the flexibility, upgrade-ability and robustness offered by rising advanced digital signal processing techniques, for future high-speed, high...

New Compensation Technique for Fiber Impairments in Ultra High Capacity Super channel Based on (QDPASK Dense wavelength division multiplex (DWDM systems

Directory of Open Access Journals (Sweden)

Ibrahim A.Murdas

2017-07-01

Full Text Available In this paper we want to increase the data rate and to get larger transmission distance, therefore we use the Advanced modulation technique QDPASK in DWDM system with low channels space. In case of long transmission distance and multi channels system both giving rise to inter channel crosstalk induced by fiber nonlinearities as a result the use of advanced modulation technique becomes difficult. In this paper Quaternary differential phase amplitude shift keying (QDPASK is designed for 32 dense wavelength division multiplexing (DWDM channels, therefore we proposed a new cascade compensation system consist of optical and digital back propagation techniques (ODBP for compensate the linear and nonlinear effects . A performance of the system was reported using QDPASK DWDM fiber-optic system for various system parameters. The research is tested in VPI maker environment.

A Code Division Technique for Multiple Element Synthetic Aperture Transmission

DEFF Research Database (Denmark)

Gran, Fredrik; Jensen, Jørgen Arendt; Jakobsson, Andreas

2004-01-01

a method in which all transmitting centers can be excited at the same time and separated at the receiver. Hereby the benefits from traditional STA can be utilized and a high fframe rate can be maintained and the images are not influenced by motion artifacts. The different centers are excited using mutually...

Microfluidic CODES: a scalable multiplexed electronic sensor for orthogonal detection of particles in microfluidic channels.

Science.gov (United States)

Liu, Ruxiu; Wang, Ningquan; Kamili, Farhan; Sarioglu, A Fatih

2016-04-21

Numerous biophysical and biochemical assays rely on spatial manipulation of particles/cells as they are processed on lab-on-a-chip devices. Analysis of spatially distributed particles on these devices typically requires microscopy negating the cost and size advantages of microfluidic assays. In this paper, we introduce a scalable electronic sensor technology, called microfluidic CODES, that utilizes resistive pulse sensing to orthogonally detect particles in multiple microfluidic channels from a single electrical output. Combining the techniques from telecommunications and microfluidics, we route three coplanar electrodes on a glass substrate to create multiple Coulter counters producing distinct orthogonal digital codes when they detect particles. We specifically design a digital code set using the mathematical principles of Code Division Multiple Access (CDMA) telecommunication networks and can decode signals from different microfluidic channels with >90% accuracy through computation even if these signals overlap. As a proof of principle, we use this technology to detect human ovarian cancer cells in four different microfluidic channels fabricated using soft lithography. Microfluidic CODES offers a simple, all-electronic interface that is well suited to create integrated, low-cost lab-on-a-chip devices for cell- or particle-based assays in resource-limited settings.

Chemical and Laser Sciences Division: Annual report, 1987

International Nuclear Information System (INIS)

1988-01-01

As the Chemical and Laser Sciences Division concludes its first year, the Division personnel can be proud of their many scientific and technical accomplishments. Among the important milestones which the Division achieved were significant demonstrations of the process performance in the Special Isotope Separation program, of beam sensing techniques for the NPB program, and of optical angular multiplexing and energy extraction from the ICF KrF laser. In addition, the Los Alamos FTS was brought to operational status and the Bright Source attained intensities on the order of 10 17 W/cm 2 . A few highlights of these and other research and development activities are presented in the following sections of this report

CodeArmor : Virtualizing the Code Space to Counter Disclosure Attacks

NARCIS (Netherlands)

Chen, Xi; Bos, Herbert; Giuffrida, Cristiano

2017-01-01

Code diversification is an effective strategy to prevent modern code-reuse exploits. Unfortunately, diversification techniques are inherently vulnerable to information disclosure. Recent diversification-aware ROP exploits have demonstrated that code disclosure attacks are a realistic threat, with an

Nuclear Physics division progress report

International Nuclear Information System (INIS)

Lees, E.W.; Longworth, G.; Scofield, C.J.

1981-07-01

Work undertaken by the Nuclear Physics Division of AERE, Harwell during 1980 is presented under the headings: (1) Nuclear Data and Technology for Nuclear Power. (2) Nuclear Studies. (3) Applications of Nuclear and Associated Techniques. (4) Accelerator Operation, Maintenance and Development. Reports, publications and conference papers presented during the period are given and members of staff listed. (U.K.)

Energy Technology Division research summary -- 1994

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

Research funded primarily by the NRC is directed toward assessing the roles of cyclic fatigue, intergranular stress corrosion cracking, and irradiation-assisted stress corrosion cracking on failures in light water reactor (LWR) piping systems, pressure vessels, and various core components. In support of the fast reactor program, the Division has responsibility for fuel-performance modeling and irradiation testing. The Division has major responsibilities in several design areas of the proposed International Thermonuclear Experimental Reactor (ITER). The Division supports the DOE in ensuring safe shipment of nuclear materials by providing extensive review of the Safety Analysis Reports for Packaging (SARPs). Finally, in the nuclear area they are investigating the safe disposal of spent fuel and waste. In work funded by DOE`s Energy Efficiency and Renewable Energy, the high-temperature superconductivity program continues to be a major focal point for industrial interactions. Coatings and lubricants developed in the division`s Tribology Section are intended for use in transportation systems of the future. Continuous fiber ceramic composites are being developed for high-performance heat engines. Nondestructive testing techniques are being developed to evaluate fiber distribution and to detect flaws. A wide variety of coatings for corrosion protection of metal alloys are being studied. These can increase lifetimes significant in a wide variety of coal combustion and gasification environments.

SPICE analysis of the charge division in resistive semiconductor nanowire diodes

International Nuclear Information System (INIS)

Guardiola, C; Money, K; Carabe, A

2014-01-01

In this paper we present an analysis of the charge division method in semiconductor nanowire Schottky diodes using an electrical model based on the SPICE simulation code. A semiconductor nanowire prototype that is simulated as an RC network and two readout electronic systems are modelled in order to understand its behaviour and to assess its application as a possible ionizing particle detector in clinical high-LET particle beams. We study the use of resistive charge division along the semiconductor nanowire to calculate the position of deposited charge generated by an ionizing particle as it crosses the nanodevice and to determine the minimal viable spatial resolution. Our aim is to demonstrate the charge division concept in resistive semiconductor nanowire diodes, and to subsequently understand the performance of these nanodevices as radiation sensors and address the design limitations of such an application

Survey of particle codes in the Magnetic Fusion Energy Program

International Nuclear Information System (INIS)

1977-12-01

In the spring of 1976, the Fusion Plasma Theory Branch of the Division of Magnetic Fusion Energy conducted a survey of all the physics computer codes being supported at that time. The purpose of that survey was to allow DMFE to prepare a description of the codes for distribution to the plasma physics community. This document is the first of several planned and covers those types of codes which treat the plasma as a group of particles

Application of ART to time-coded emission tomography

International Nuclear Information System (INIS)

Koral, K.F.; Rogers, W.L.

1979-01-01

Devices for single-photon emission tomography currently take projections either in a plane over a full angular range (0-360 0 ) or in a volume with a limited angular range. The planar, pseudo-random, time-coded aperture, in conjunction with an Anger camera, is a device of the limited angular range type. It employs multiple pinholes whose transmission varies as a function of time. Previously, image reconstruction was accomplished by simple back-projection of coefficients obtained by time-correlating pinhole transmission with detector-element count rate, resulting in a low-contrast image. Using the Algebraic Reconstruction Technique (ART) a method is introduced for division of the correlation coefficients into subsets allowing the three-dimensional reconstruction to be accomplished on a minicomputer. Results from simulations and experimental phantom data show that ART improves depth resolution compared to back-projection, that under-relaxation produces better images in the case of noisy data, and that the division of the correlation coefficients into subsets has no effect on quality. The images depict the expected resolution degradation in the direction normal to the detector plane due to the limited angular range of projections but yield quantitative results whose relative values are good, even though attenuation is neglected. (author)

Verification of Remote Inspection Techniques for Reactor Internal Structures of Liquid Metal Reactor

International Nuclear Information System (INIS)

Joo, Young Sang; Lee, Jae Han

2007-02-01

The reactor internal structures and components of a liquid metal reactor (LMR) are submerged in hot sodium of reactor vessel. The division 3 of ASME code section XI specifies the visual inspection as major in-service inspection (ISI) methods of reactor internal structures and components. Reactor internals of LMR can not be visually examined due to opaque liquid sodium. The under-sodium viewing techniques using an ultrasonic wave should be applied for the visual inspection of reactor internals. Recently, an ultrasonic waveguide sensor with a strip plate has been developed for an application to the under-sodium inspection. In this study, visualization technique, ranging technique and monitoring technique have been suggested for the remote inspection of reactor internals by using the waveguide sensor. The feasibility of these remote inspection techniques using ultrasonic waveguide sensor has been evaluated by an experimental verification

Verification of Remote Inspection Techniques for Reactor Internal Structures of Liquid Metal Reactor

Energy Technology Data Exchange (ETDEWEB)

Joo, Young Sang; Lee, Jae Han

2007-02-15

The reactor internal structures and components of a liquid metal reactor (LMR) are submerged in hot sodium of reactor vessel. The division 3 of ASME code section XI specifies the visual inspection as major in-service inspection (ISI) methods of reactor internal structures and components. Reactor internals of LMR can not be visually examined due to opaque liquid sodium. The under-sodium viewing techniques using an ultrasonic wave should be applied for the visual inspection of reactor internals. Recently, an ultrasonic waveguide sensor with a strip plate has been developed for an application to the under-sodium inspection. In this study, visualization technique, ranging technique and monitoring technique have been suggested for the remote inspection of reactor internals by using the waveguide sensor. The feasibility of these remote inspection techniques using ultrasonic waveguide sensor has been evaluated by an experimental verification.

Investigation into constant envelope orthogonal frequency division multiplexing for polarization-division multiplexing coherent optical communication

Science.gov (United States)

Li, Yupeng; Ding, Ding

2017-09-01

Benefiting from the high spectral efficiency and low peak-to-average power ratio, constant envelope orthogonal frequency division multiplexing (OFDM) is a promising technique in coherent optical communication. Polarization-division multiplexing (PDM) has been employed as an effective way to double the transmission capacity in the commercial 100 Gb/s PDM-QPSK system. We investigated constant envelope OFDM together with PDM. Simulation results show that the acceptable maximum launch power into the fiber improves 10 and 6 dB for 80- and 320-km transmission, respectively (compared with the conventional PDM OFDM system). The maximum reachable distance of the constant envelope OFDM system is able to reach 800 km, and even 1200 km is reachable if an ideal erbium doped fiber amplifier is employed.

An Analysis of the Changes in Communication Techniques in the Italian Codes of Medical Deontology.

Science.gov (United States)

Conti, Andrea Alberto

2017-04-28

The code of deontology of the Italian National Federation of the Colleges of Physicians, Surgeons and Dentists (FNOMCeO) contains the principles and rules to which the professional medical practitioner must adhere. This work identifies and analyzes the medical-linguistic choices and the expressive techniques present in the different editions of the code, and evaluates their purpose and function, focusing on the first appearance and the subsequent frequency of key terms. Various aspects of the formal and expressive revisions of the eight editions of the Codes of Medical Deontology published after the Second World War (from 1947/48 to 2014) are here presented, starting from a brief comparison with the first edition of 1903. Formal characteristics, choices of medical terminology and the introduction of new concepts and communicative attitudes are here identified and evaluated. This paper, in presenting a quantitative and epistemological analysis of variations, modifications and confirmations in the different editions of the Italian code of medical deontology over the last century, enucleates and demonstrates the dynamic paradigm of changing attitudes in the medical profession. This analysis shows the evolution in medical-scientific communication as embodied in the Italian code of medical deontology. This code, in its adoption, changes and adaptations, as evidenced in its successive editions, bears witness to the expressions and attitudes pertinent to and characteristic of the deontological stance of the medical profession during the twentieth century.

PERFORMANCE ANALYSIS OF OPTICAL CDMA SYSTEM USING VC CODE FAMILY UNDER VARIOUS OPTICAL PARAMETERS

Directory of Open Access Journals (Sweden)

HASSAN YOUSIF AHMED

2012-06-01

Full Text Available The intent of this paper is to study the performance of spectral-amplitude coding optical code-division multiple-access (OCDMA systems using Vector Combinatorial (VC code under various optical parameters. This code can be constructed by an algebraic way based on Euclidian vectors for any positive integer number. One of the important properties of this code is that the maximum cross-correlation is always one which means that multi-user interference (MUI and phase induced intensity noise are reduced. Transmitter and receiver structures based on unchirped fiber Bragg grating (FBGs using VC code and taking into account effects of the intensity, shot and thermal noise sources is demonstrated. The impact of the fiber distance effects on bit error rate (BER is reported using a commercial optical systems simulator, virtual photonic instrument, VPITM. The VC code is compared mathematically with reported codes which use similar techniques. We analyzed and characterized the fiber link, received power, BER and channel spacing. The performance and optimization of VC code in SAC-OCDMA system is reported. By comparing the theoretical and simulation results taken from VPITM, we have demonstrated that, for a high number of users, even if data rate is higher, the effective power source is adequate when the VC is used. Also it is found that as the channel spacing width goes from very narrow to wider, the BER decreases, best performance occurs at a spacing bandwidth between 0.8 and 1 nm. We have shown that the SAC system utilizing VC code significantly improves the performance compared with the reported codes.

BER performance comparison of optical CDMA systems with/without turbo codes

Science.gov (United States)

Kulkarni, Muralidhar; Chauhan, Vijender S.; Dutta, Yashpal; Sinha, Ravindra K.

2002-08-01

In this paper, we have analyzed and simulated the BER performance of a turbo coded optical code-division multiple-access (TC-OCDMA) system. A performance comparison has been made between uncoded OCDMA and TC-OCDMA systems employing various OCDMA address codes (optical orthogonal codes (OOCs), Generalized Multiwavelength Prime codes (GMWPC's), and Generalized Multiwavelength Reed Solomon code (GMWRSC's)). The BER performance of TC-OCDMA systems has been analyzed and simulated by varying the code weight of address code employed by the system. From the simulation results, it is observed that lower weight address codes can be employed for TC-OCDMA systems that can have the equivalent BER performance of uncoded systems employing higher weight address codes for a fixed number of active users.

Peak-to-average power ratio reduction in orthogonal frequency division multiplexing-based visible light communication systems using a modified partial transmit sequence technique

Science.gov (United States)

Liu, Yan; Deng, Honggui; Ren, Shuang; Tang, Chengying; Qian, Xuewen

2018-01-01

We propose an efficient partial transmit sequence technique based on genetic algorithm and peak-value optimization algorithm (GAPOA) to reduce high peak-to-average power ratio (PAPR) in visible light communication systems based on orthogonal frequency division multiplexing (VLC-OFDM). By analysis of hill-climbing algorithm's pros and cons, we propose the POA with excellent local search ability to further process the signals whose PAPR is still over the threshold after processed by genetic algorithm (GA). To verify the effectiveness of the proposed technique and algorithm, we evaluate the PAPR performance and the bit error rate (BER) performance and compare them with partial transmit sequence (PTS) technique based on GA (GA-PTS), PTS technique based on genetic and hill-climbing algorithm (GH-PTS), and PTS based on shuffled frog leaping algorithm and hill-climbing algorithm (SFLAHC-PTS). The results show that our technique and algorithm have not only better PAPR performance but also lower computational complexity and BER than GA-PTS, GH-PTS, and SFLAHC-PTS technique.

Space-Time Coded MC-CDMA: Blind Channel Estimation, Identifiability, and Receiver Design

Directory of Open Access Journals (Sweden)

Li Hongbin

2002-01-01

Full Text Available Integrating the strengths of multicarrier (MC modulation and code division multiple access (CDMA, MC-CDMA systems are of great interest for future broadband transmissions. This paper considers the problem of channel identification and signal combining/detection schemes for MC-CDMA systems equipped with multiple transmit antennas and space-time (ST coding. In particular, a subspace based blind channel identification algorithm is presented. Identifiability conditions are examined and specified which guarantee unique and perfect (up to a scalar channel estimation when knowledge of the noise subspace is available. Several popular single-user based signal combining schemes, namely the maximum ratio combining (MRC and the equal gain combining (EGC, which are often utilized in conventional single-transmit-antenna based MC-CDMA systems, are extended to the current ST-coded MC-CDMA (STC-MC-CDMA system to perform joint combining and decoding. In addition, a linear multiuser minimum mean-squared error (MMSE detection scheme is also presented, which is shown to outperform the MRC and EGC at some increased computational complexity. Numerical examples are presented to evaluate and compare the proposed channel identification and signal detection/combining techniques.

Energy Technology Division research summary -- 1994

International Nuclear Information System (INIS)

1994-09-01

Research funded primarily by the NRC is directed toward assessing the roles of cyclic fatigue, intergranular stress corrosion cracking, and irradiation-assisted stress corrosion cracking on failures in light water reactor (LWR) piping systems, pressure vessels, and various core components. In support of the fast reactor program, the Division has responsibility for fuel-performance modeling and irradiation testing. The Division has major responsibilities in several design areas of the proposed International Thermonuclear Experimental Reactor (ITER). The Division supports the DOE in ensuring safe shipment of nuclear materials by providing extensive review of the Safety Analysis Reports for Packaging (SARPs). Finally, in the nuclear area they are investigating the safe disposal of spent fuel and waste. In work funded by DOE's Energy Efficiency and Renewable Energy, the high-temperature superconductivity program continues to be a major focal point for industrial interactions. Coatings and lubricants developed in the division's Tribology Section are intended for use in transportation systems of the future. Continuous fiber ceramic composites are being developed for high-performance heat engines. Nondestructive testing techniques are being developed to evaluate fiber distribution and to detect flaws. A wide variety of coatings for corrosion protection of metal alloys are being studied. These can increase lifetimes significant in a wide variety of coal combustion and gasification environments

Performance Analysis of SAC Optical PPM-CDMA System-Based Interference Rejection Technique

Science.gov (United States)

Alsowaidi, N.; Eltaif, Tawfig; Mokhtar, M. R.

2016-03-01

In this paper, we aim to theoretically analyse optical code division multiple access (OCDMA) system that based on successive interference cancellation (SIC) using pulse position modulation (PPM), considering the interference between the users, imperfection cancellation occurred during the cancellation process and receiver noises. Spectral amplitude coding (SAC) scheme is used to suppress the overlapping between the users and reduce the receiver noises effect. The theoretical analysis of the multiple access interference (MAI)-limited performance of this approach indicates the influence of the size of M-ary PPM on OCDMA system. The OCDMA system performance improves with increasing M-ary PPM. Therefore, it was found that the SIC/SAC-OCDMA system using PPM technique along with modified prime (MPR) codes used as signature sequence code offers significant improvement over the one without cancellation and it can support up to 103 users at the benchmarking value of bit error rate (BER) = 10-9 with prime number p = 11 while the system without cancellation scheme can support only up to 52 users.

Variable weight spectral amplitude coding for multiservice OCDMA networks

Science.gov (United States)

Seyedzadeh, Saleh; Rahimian, Farzad Pour; Glesk, Ivan; Kakaee, Majid H.

2017-09-01

The emergence of heterogeneous data traffic such as voice over IP, video streaming and online gaming have demanded networks with capability of supporting quality of service (QoS) at the physical layer with traffic prioritisation. This paper proposes a new variable-weight code based on spectral amplitude coding for optical code-division multiple-access (OCDMA) networks to support QoS differentiation. The proposed variable-weight multi-service (VW-MS) code relies on basic matrix construction. A mathematical model is developed for performance evaluation of VW-MS OCDMA networks. It is shown that the proposed code provides an optimal code length with minimum cross-correlation value when compared to other codes. Numerical results for a VW-MS OCDMA network designed for triple-play services operating at 0.622 Gb/s, 1.25 Gb/s and 2.5 Gb/s are considered.

Demonstration of two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded longperiod fiber gratings formed in dispersion-compensating fiber with inner-cladding structure

DEFF Research Database (Denmark)

Kim, Sun-Jong; Eom, T.J.; Kim, T.Y.

2005-01-01

A two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in a dispersion-compensating fiber (DCF) is demonstrated. Our results show that the sensitivity of cladding modes to the refractive index change on the cladding...... surface is greatly reduced by utilizing the inner-cladding mode of the DCF. Two pairs of encoder/decoder are constructed and the performance is evaluated by measuring bit error rate (BER). With an interferer, a BER of 1.5 X 10(-12) is measured at a received optical power of -6 dBm....

Optical CDMA with Embedded Spectral-Polarization Coding over Double Balanced Differential-Detector

Science.gov (United States)

Huang, Jen-Fa; Yen, Chih-Ta; Chen, Bo-Hau

A spectral-polarization coding (SPC) optical code-division multiple-access (OCDMA) configuration structured over arrayed-waveguide grating (AWG) router is proposed. The polarization-division double balanced detector is adopted to execute difference detection and enhances system performance. The signal-to-noise ratio (SNR) is derived by taking the effect of PIIN into account. The result indicates that there would be up to 9-dB SNR improvement than the conventional spectral-amplitude coding (SAC) structures with Walsh-Hadamard codes. Mathematical deriving results of the SNR demonstrate the system embedded with the orthogonal state of polarization (SOP) will suppress effectively phase-induced intensity noise (PIIN). In addition, we will analyze the relations about bit error rate (BER) vs. the number of active users under the different encoding schemes and compare them with our proposed scheme. The BER vs. the effective power under the different encoding scheme with the same number of simultaneous active user conditions are also revealed. Finally, the polarization-matched factor and the difference between simulated and experimental values are discussed.

Progress report: Physics Division, 1982 January 1 to March 1

International Nuclear Information System (INIS)

1982-05-01

The work of the Physics Division at Chalk River Nuclear Laboratories during the quarter is presented. Areas of interest include nuclear physics, neutron sources, the development of a superconducting cyclotron, high current proton accelerators and electron accelerators, diffraction studies and other solid state physics work in organic and inorganic substances, and computer codes. The operation of the MP tandem accelerator and the computer facilities is reviewed

Fuel Chemistry Division: progress report for 1985

International Nuclear Information System (INIS)

1988-01-01

Fuel Chemistry Division was formed in May 1985 to give a larger emphasis on the research and development in chemistry of the nuclear fuel cycle. The areas of research in Fuel Chemistry Division are fuel development and its chemical quality control, understanding of the fuel behaviour and post irradiation examinations, chemistry of reprocessing and waste management processes as also the basic aspects of actinide and relevant fission product elements. This report summarises the work by the staff of the Division during 1985 and also some work from the previous periods which was not reported in the progress reports of the Radiochemistry Division. The work related to the FBTR fuel was one of the highlights during this period. In the area of process chemistry useful work has been carried out for processing of plutonium bearing solutions. In the area of mass spectrometry, the determination of trace constituents by spark source mass spectrometry has been a major area of research. Significant progress has also been made in the use of alpha spectromet ry techniques for the determination of plutonium in dissolver solution and other samples. The technology of plutonium utilisation is quite complex and the Division would continue to look into the chemical aspects of this technology and provide the necessary base for future developments in this area. (author)

Some optimizations of the animal code

International Nuclear Information System (INIS)

Fletcher, W.T.

1975-01-01

Optimizing techniques were performed on a version of the ANIMAL code (MALAD1B) at the source-code (FORTRAN) level. Sample optimizing techniques and operations used in MALADOP--the optimized version of the code--are presented, along with a critique of some standard CDC 7600 optimizing techniques. The statistical analysis of total CPU time required for MALADOP and MALAD1B shows a run-time saving of 174 msec (almost 3 percent) in the code MALADOP during one time step

Theoretical analysis and simulation of a code division multiple access system (cdma for secure signal transmission in wideband channels

Directory of Open Access Journals (Sweden)

Stevan M. Berber

2014-06-01

Code Division Multiple Access (CDMA technique which allows communications of multiple users in the same communication system. This is achieved in such a way that each user is assigned a unique code sequence, which is used at the receiver side to discover the information dedicated to that user. These systems belong to the group of communication systems for direct sequence spread spectrum systems. Traditionally, CDMA systems use binary orthogonal spreading codes. In this paper, a mathematical model and simulation of a CDMA system based on the application of non-binary, precisely speaking, chaotic spreading sequences. In their nature, these sequences belong to random sequences with infinite periodicity, and due to that they are appropriate for applications in the systems that provide enhanced security against interception and secrecy in signal transmission. Numerous papers are dedicated to the development of CDMA systems in flat fading channels. This paper presents the results of these systems analysis for the case when frequency selective fading is present in the channel. In addition, the paper investigates a possibility of using interleaving techniques to mitigate fading in a wideband channel with the frequency selective fading. Basic structure of a CDMA communication system and its operation In this paper, a CDMA system block schematic is ppresented and the function of all blocks is explained. Notation  to be used in the paper is introduced. Chaotic sequences are defined and explained in accordance with the method of their generation. A wideband channel with frequency selective fading is defined by its impulse response function. Theoretical analysis of a CDMA system with flat fading in a narrowband channel A narrowband channel and flat fading are defined. A mathematical analysis of the system is conducted by presenting the signal expressions at vital points in the transmitter and receiver. The expression of the signal at the output of the sequence correlator is

Improved numerical grid generation techniques for the B2 edge plasma code

International Nuclear Information System (INIS)

Stotler, D.P.; Coster, D.P.

1992-06-01

Techniques used to generate grids for edge fluid codes such as B2 from numerically computed equilibria are discussed. Fully orthogonal, numerically derived grids closely resembling analytically prescribed meshes can be obtained. But, the details of the poloidal field can vary, yielding significantly different plasma parameters in the simulations. The magnitude of these differences is consistent with the predictions of an analytic model of the scrape-off layer. Both numerical and analytic grids are insensitive to changes in their defining parameters. Methods for implementing nonorthogonal boundaries in these meshes are also presented; they differ slightly from those required for fully orthogonal grids

Radiation transport simulation in gamma irradiator systems using E G S 4 Monte Carlo code and dose mapping calculations based on point kernel technique

International Nuclear Information System (INIS)

Raisali, G.R.

1992-01-01

A series of computer codes based on point kernel technique and also Monte Carlo method have been developed. These codes perform radiation transport calculations for irradiator systems having cartesian, cylindrical and mixed geometries. The monte Carlo calculations, the computer code 'EGS4' has been applied to a radiation processing type problem. This code has been acompanied by a specific user code. The set of codes developed include: GCELLS, DOSMAPM, DOSMAPC2 which simulate the radiation transport in gamma irradiator systems having cylinderical, cartesian, and mixed geometries, respectively. The program 'DOSMAP3' based on point kernel technique, has been also developed for dose rate mapping calculations in carrier type gamma irradiators. Another computer program 'CYLDETM' as a user code for EGS4 has been also developed to simulate dose variations near the interface of heterogeneous media in gamma irradiator systems. In addition a system of computer codes 'PRODMIX' has been developed which calculates the absorbed dose in the products with different densities. validation studies of the calculated results versus experimental dosimetry has been performed and good agreement has been obtained

Bandwidth efficient coding

CERN Document Server

Anderson, John B

2017-01-01

Bandwidth Efficient Coding addresses the major challenge in communication engineering today: how to communicate more bits of information in the same radio spectrum. Energy and bandwidth are needed to transmit bits, and bandwidth affects capacity the most. Methods have been developed that are ten times as energy efficient at a given bandwidth consumption as simple methods. These employ signals with very complex patterns and are called "coding" solutions. The book begins with classical theory before introducing new techniques that combine older methods of error correction coding and radio transmission in order to create narrowband methods that are as efficient in both spectrum and energy as nature allows. Other topics covered include modulation techniques such as CPM, coded QAM and pulse design.

Kinetics of human lymphocyte division and chromosomal radiosensitivity

Energy Technology Data Exchange (ETDEWEB)

Bianchi, N O; Bianchi, M S; Larramendy, M [Instituto Multidisciplinario de Biologia Celular, La Plata (Argentinia)

1979-12-01

Human blood from normal donors was irradiated with 200 R during the G/sub 0/ phase, and the X-ray sensitivity of early and late dividing lymphocytes in culture was expressed as percentage of induced dicentrics. Cells in first or subsequent divisions were individualized by BrdU-Giemsa techniques. Lymphocytes in the first division at 40, 44 and 72 h after the start of culture had a lower sensitivity to radiation than lymphocytes making their first division at 48, 52 and 56 h. It was observed that: (a) the combination of radiation followed by BrdU did not increase the clastoyenic action of X-rays, (b)X-rays in the dose and duration used in our cultures did not increase the frequency of SCEs, and (c) minor changes in culture conditions probably influenced the frequency of SCEs.

Dynamic quality of service differentiation using fixed code weight in optical CDMA networks

Science.gov (United States)

Kakaee, Majid H.; Essa, Shawnim I.; Abd, Thanaa H.; Seyedzadeh, Saleh

2015-11-01

The emergence of network-driven applications, such as internet, video conferencing, and online gaming, brings in the need for a network the environments with capability of providing diverse Quality of Services (QoS). In this paper, a new code family of novel spreading sequences, called a Multi-Service (MS) code, has been constructed to support multiple services in Optical- Code Division Multiple Access (CDMA) system. The proposed method uses fixed weight for all services, however reducing the interfering codewords for the users requiring higher QoS. The performance of the proposed code is demonstrated using mathematical analysis. It shown that the total number of served users with satisfactory BER of 10-9 using NB=2 is 82, while they are only 36 and 10 when NB=3 and 4 respectively. The developed MS code is compared with variable-weight codes such as Variable Weight-Khazani Syed (VW-KS) and Multi-Weight-Random Diagonal (MW-RD). Different numbers of basic users (NB) are used to support triple-play services (audio, data and video) with different QoS requirements. Furthermore, reference to the BER of 10-12, 10-9, and 10-3 for video, data and audio, respectively, the system can support up to 45 total users. Hence, results show that the technique can clearly provide a relative QoS differentiation with lower value of basic users can support larger number of subscribers as well as better performance in terms of acceptable BER of 10-9 at fixed code weight.

Performance analysis of wavelength/spatial coding system with fixed in-phase code matrices in OCDMA network

Science.gov (United States)

Tsai, Cheng-Mu; Liang, Tsair-Chun

2011-12-01

This paper proposes a wavelength/spatial (W/S) coding system with fixed in-phase code (FIPC) matrix in the optical code-division multiple-access (OCDMA) network. A scheme is presented to form the FIPC matrix which is applied to construct the W/S OCDMA network. The encoder/decoder in the W/S OCDMA network is fully able to eliminate the multiple-access-interference (MAI) at the balanced photo-detectors (PD), according to fixed in-phase cross correlation. The phase-induced intensity noise (PIIN) related to the power square is markedly suppressed in the receiver by spreading the received power into each PD while the net signal power is kept the same. Simulation results show that the W/S OCDMA network based on the FIPC matrices cannot only completely remove the MAI but effectively suppress the PIIN to upgrade the network performance.

Adaptive Code Division Multiple Access Protocol for Wireless Network-on-Chip Architectures

Science.gov (United States)

Vijayakumaran, Vineeth

Massive levels of integration following Moore's Law ushered in a paradigm shift in the way on-chip interconnections were designed. With higher and higher number of cores on the same die traditional bus based interconnections are no longer a scalable communication infrastructure. On-chip networks were proposed enabled a scalable plug-and-play mechanism for interconnecting hundreds of cores on the same chip. Wired interconnects between the cores in a traditional Network-on-Chip (NoC) system, becomes a bottleneck with increase in the number of cores thereby increasing the latency and energy to transmit signals over them. Hence, there has been many alternative emerging interconnect technologies proposed, namely, 3D, photonic and multi-band RF interconnects. Although they provide better connectivity, higher speed and higher bandwidth compared to wired interconnects; they also face challenges with heat dissipation and manufacturing difficulties. On-chip wireless interconnects is one other alternative proposed which doesn't need physical interconnection layout as data travels over the wireless medium. They are integrated into a hybrid NOC architecture consisting of both wired and wireless links, which provides higher bandwidth, lower latency, lesser area overhead and reduced energy dissipation in communication. However, as the bandwidth of the wireless channels is limited, an efficient media access control (MAC) scheme is required to enhance the utilization of the available bandwidth. This thesis proposes using a multiple access mechanism such as Code Division Multiple Access (CDMA) to enable multiple transmitter-receiver pairs to send data over the wireless channel simultaneously. It will be shown that such a hybrid wireless NoC with an efficient CDMA based MAC protocol can significantly increase the performance of the system while lowering the energy dissipation in data transfer. In this work it is shown that the wireless NoC with the proposed CDMA based MAC protocol

Synthesizing Modular Invariants for Synchronous Code

Directory of Open Access Journals (Sweden)

Pierre-Loic Garoche

2014-12-01

Full Text Available In this paper, we explore different techniques to synthesize modular invariants for synchronous code encoded as Horn clauses. Modular invariants are a set of formulas that characterizes the validity of predicates. They are very useful for different aspects of analysis, synthesis, testing and program transformation. We describe two techniques to generate modular invariants for code written in the synchronous dataflow language Lustre. The first technique directly encodes the synchronous code in a modular fashion. While in the second technique, we synthesize modular invariants starting from a monolithic invariant. Both techniques, take advantage of analysis techniques based on property-directed reachability. We also describe a technique to minimize the synthesized invariants.

Demonstration of two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in dispersion-compensating fiber with inner-cladding structure

Science.gov (United States)

Kim, Sun-Jong; Eom, Tae-Jung; Kim, Tae-Young; Lee, Byeong Ha; Park, Chang-Soo

2005-09-01

A two-user, 10-Gbits/s optical code-division multiple-access system implemented by using cascaded long-period fiber gratings formed in a dispersion-compensating fiber (DCF) is demonstrated. Our results show that the sensitivity of cladding modes to the refractive index change on the cladding surface is greatly reduced by utilizing the inner-cladding mode of the DCF. Two pairs of encoder/decoder are constructed and the performance is evaluated by measuring bit error rate (BER). With an interferer, a BER of 1.5×10-12 is measured at a received optical power of -6 dBm.

Spectroscopy Division progress report for January 1985-December 1986

International Nuclear Information System (INIS)

Bellary, V.P.; Balasubramanian, T.K.

1987-01-01

The present report describes the activities of the Spectroscopy Division during the period January 1985-December 1986. Besides meeting the analytical requirements connected with the nuclear energy programmes and the related research and development projects, the Division has continued its efforts to develop and set-up new techniques to improve the speed and efficiency of the analytical capabilities and carry out basic research on atomic and molecular systems of importance to the programmes of the research centre. In the first section of the report, two feature articles, one on Laser Magnetic Resonance Spectroscopy and the other on Nuclear Spins, Moments and Charge Radii of short-lived isotopes and isomers using Laser Spectroscopic Techniques are included. The second section deals with the characterisation of the materials using optical emission, X-ray fluorescence and X-ray excited optical luminescence techniques. Work connected with basic research on atomic and molecular systems is described in the third section. Work on atomic systems includes high resolution studies on rare-earth ions in free and condensed states and the evaluation of the nuclear properties of short-lived radioactive elements. Work on molecular systems includes theoretical aspects pertaining to rotational intensities in forbidden transitions of diatomic molecules, high resolution spectral studies of diatomic molecules and free radicals, laser spectroscopy of alkali dimers. The fourth and fifth sections deal with the work concerning the designing and fabrication of sophisticated optical equipments and electronic components and system required for the various research and development programmes in the Division. Members of the Division continued to participate in the teaching programmes, guiding research leading to M.Sc. and Ph.D. degrees, training in spectrochemical analysis and in symposia and conferences. These activities are described in the last section of the report. (author)

Construction of new quantum MDS codes derived from constacyclic codes

Science.gov (United States)

Taneja, Divya; Gupta, Manish; Narula, Rajesh; Bhullar, Jaskaran

Obtaining quantum maximum distance separable (MDS) codes from dual containing classical constacyclic codes using Hermitian construction have paved a path to undertake the challenges related to such constructions. Using the same technique, some new parameters of quantum MDS codes have been constructed here. One set of parameters obtained in this paper has achieved much larger distance than work done earlier. The remaining constructed parameters of quantum MDS codes have large minimum distance and were not explored yet.

Fast frequency hopping codes applied to SAC optical CDMA network

Science.gov (United States)

Tseng, Shin-Pin

2015-06-01

This study designed a fast frequency hopping (FFH) code family suitable for application in spectral-amplitude-coding (SAC) optical code-division multiple-access (CDMA) networks. The FFH code family can effectively suppress the effects of multiuser interference and had its origin in the frequency hopping code family. Additional codes were developed as secure codewords for enhancing the security of the network. In considering the system cost and flexibility, simple optical encoders/decoders using fiber Bragg gratings (FBGs) and a set of optical securers using two arrayed-waveguide grating (AWG) demultiplexers (DeMUXs) were also constructed. Based on a Gaussian approximation, expressions for evaluating the bit error rate (BER) and spectral efficiency (SE) of SAC optical CDMA networks are presented. The results indicated that the proposed SAC optical CDMA network exhibited favorable performance.

An implicit Smooth Particle Hydrodynamic code

Energy Technology Data Exchange (ETDEWEB)

Knapp, Charles E. [Univ. of New Mexico, Albuquerque, NM (United States)

2000-05-01

An implicit version of the Smooth Particle Hydrodynamic (SPH) code SPHINX has been written and is working. In conjunction with the SPHINX code the new implicit code models fluids and solids under a wide range of conditions. SPH codes are Lagrangian, meshless and use particles to model the fluids and solids. The implicit code makes use of the Krylov iterative techniques for solving large linear-systems and a Newton-Raphson method for non-linear corrections. It uses numerical derivatives to construct the Jacobian matrix. It uses sparse techniques to save on memory storage and to reduce the amount of computation. It is believed that this is the first implicit SPH code to use Newton-Krylov techniques, and is also the first implicit SPH code to model solids. A description of SPH and the techniques used in the implicit code are presented. Then, the results of a number of tests cases are discussed, which include a shock tube problem, a Rayleigh-Taylor problem, a breaking dam problem, and a single jet of gas problem. The results are shown to be in very good agreement with analytic solutions, experimental results, and the explicit SPHINX code. In the case of the single jet of gas case it has been demonstrated that the implicit code can do a problem in much shorter time than the explicit code. The problem was, however, very unphysical, but it does demonstrate the potential of the implicit code. It is a first step toward a useful implicit SPH code.

Femtosecond Laser System for Research on High-Speed Optical Transmultiplexing and Coding

National Research Council Canada - National Science Library

Weiner, Andrew

1997-01-01

.... This would fill an important need in both TDM packet networks and bit-parallel WDM linds. The research also aims at experimental tests of an ultrashort pulse code-division, multiple-access (CDMA...

Spatial Encoding Using a Code Division Technique for Fast Ultrasound Imaging

DEFF Research Database (Denmark)

Gran, Fredrik; Jensen, Jørgen Arendt

2008-01-01

the underlying theory and to test the feasibility in a physical system. The method has been evaluated in simulations using Field II in which the point-spread functions were simulated for different depths for a 7 MHz linear array transducer. A signal-to-noise ratio (SNR) simulation also was included in the study...... in which an improvement in SNR of ∼1.5 dB was attained compared to the standard synthetic transmit aperture (STA) firing scheme. Considering the amount of energy transmitted, this value is low. A plausible explanation is given that is verified in simulation. The method also was tested in an experimental...

A novel technique to increase the capacity of code division multiple ...

African Journals Online (AJOL)

user

accommodate more number of users than the processing gain of the system. .... dimensional vector space causing an increase in modulation complexity and reduced ...... The simulation results of the proposed scheme implemented in MATLAB ...

Spectral/spatial optical CDMA code based on Diagonal Eigenvalue Unity

Science.gov (United States)

Najjar, Monia; Jellali, Nabiha; Ferchichi, Moez; Rezig, Houria

2017-11-01

A new two dimensional Diagonal Eigenvalue Unity (2D-DEU) code is developed for the spectral⧹spatial optical code division multiple access (OCDMA) system. It has a lower cross correlation value compared to two dimensional diluted perfect difference (2D-DPD), two dimensional Extended Enhanced Double Weight (2D-Extended-EDW) codes. Also, for the same code length, the number of users can be generated by the 2D-DEU code is higher than that provided by the others codes. The Bit Error Rate (BER) numerical analysis is developed by considering the effects of shot noise, phase induced intensity noise (PIIN), and thermal noise. The main result shows that BER is strongly affected by PIIN for the higher source power. The 2D-DEU code performance is compared with 2D-DPD, 2D-Extended-EDW and two dimensional multi-diagonals (2D-MD) codes. This comparison proves that the proposed 2D-DEU system outperforms the related codes.

Research on the coding and decoding technology of the OCDMA system

Science.gov (United States)

Li, Ping; Wang, Yuru; Lan, Zhenping; Wang, Jinpeng; Zou, Nianyu

2015-12-01

Optical Code Division Multiplex Access, OCDMA, is a kind of new technology which is combined the wireless CDMA technology and the optical fiber communication technology together. The address coding technology in OCDMA system has been researched. Besides, the principle of the codec based on optical fiber delay line and non-coherent spectral domain encoding and decoding has been introduced and analysed, and the results was verified by experiment.

Variable-length code construction for incoherent optical CDMA systems

Science.gov (United States)

Lin, Jen-Yung; Jhou, Jhih-Syue; Wen, Jyh-Horng

2007-04-01

The purpose of this study is to investigate the multirate transmission in fiber-optic code-division multiple-access (CDMA) networks. In this article, we propose a variable-length code construction for any existing optical orthogonal code to implement a multirate optical CDMA system (called as the multirate code system). For comparison, a multirate system where the lower-rate user sends each symbol twice is implemented and is called as the repeat code system. The repetition as an error-detection code in an ARQ scheme in the repeat code system is also investigated. Moreover, a parallel approach for the optical CDMA systems, which is proposed by Marić et al., is also compared with other systems proposed in this study. Theoretical analysis shows that the bit error probability of the proposed multirate code system is smaller than other systems, especially when the number of lower-rate users is large. Moreover, if there is at least one lower-rate user in the system, the multirate code system accommodates more users than other systems when the error probability of system is set below 10 -9.

Progress toward NuPack, the ASME code for Type B containments

International Nuclear Information System (INIS)

Turula, P.

1995-01-01

This paper presented a brief status report on the development of an ASME Code Division for nuclear packaging and discussed some of the more interesting policy decisions as to what is and is not covered in terms of analytical methods, criteria, scope, and other aspects. The process of the development of this Division has been very slow and inconsistent. There were many participants with many diverse interests. The Division 3 rules are close to being ready to be issued. They are a compromise between many needs and the result is certainly not perfect. Opportunities for fine tuning and expanding this document will present themselves after it is issued as future needs become clear

How Equalization Techniques Affect the TCP Performance of MC-CDMA Systems in Correlated Fading Channels

Directory of Open Access Journals (Sweden)

Giacomo Leonardi

2007-12-01

Full Text Available This paper investigates the impact of several equalization techniques for multicarrier code division multiple access systems on the performance at both lower and upper layers (i.e., physical and TCP layers. Classical techniques such as maximal ratio combining, equal gain combining, orthogonality restoring combining, minimum mean square error, as well as a partial equalization (PE are investigated in time- and frequency-correlated fading channels with various numbers of interferers. Their impact on the performance at upper level is then studied. The results are obtained through an integrated simulation platform carefully reproducing all main aspects affecting the quality of service perceived by the final user, allowing an investigation of the real gain produced by signal processing techniques at TCP level.

Radiochemistry Division: triennial progress report (for) 1983-1985

International Nuclear Information System (INIS)

Datta, T.

1987-01-01

The present report includes contributions pertaining to the studies of nuclear and chemical properties of actinides. These studies have been mostly concerned with the basic investigation, besides the research and development work connected with chemical quality control of plutonium-based fuels for trace metallic constituents. The nuclear properties are being studied in the Nuclear Chemistry and Instrumentation Section while the chemical properties are being studied in the Actinide Chemistry Section and the Spectroscopy Section. The work in the Actinide Chemistry Section deals essentially with properties of ions in solutions and preparation of solid compounds, to understand the complexing behaviour of actinides. The work in the Spectroscopy Section is concerned essentially with the study of actinide solids using EPR, TSL and optical spectroscopic techniques. The considerable advances made in the basic study of actinides are reflected in the number of publications in well-known international journals. The research and development work of the Division is fully supported by Instrumentation Group of the Division which looks after the maintenance of instruments of not only the Radiochemistry Division but also the Fuel Chemistry Division and design and fabrication of special electronic instruments needed for the research and development work. (author)

A study on the radionuclide migration by means of the code LISA

International Nuclear Information System (INIS)

Frenquellucci, F.; Deserti, M.

1989-01-01

LISA code (Long Term Isolation Safety Assessment) has been developed by J.R.C. EUROATOM Ispra (Radiochemistry Division) and it's utilized in order to study migration of radionuclides through porous media. Aim of the present work is to analyze LISA's input and output files. A brief description of the code is also performed. As LISA is a research and in development code, its structure is rather complex and an exhaustive description of input/output files is helpful for the user. Version 3 of LISA code, loaded on ENEA's IBM 3090, is avaylable by ENEA-VEL Bologna

Capacity of Wavelength and Time Division Multiplexing for Quasi-Distributed Measurement Using Fiber Bragg Gratings

Directory of Open Access Journals (Sweden)

Marcel Fajkus

2015-01-01

Full Text Available In this paper, an analysis of the use of wavelength and time division multiplexing techniques for quasi-distributed measurement in uniform fiber Bragg gratings is presented. To date, publications have concentrated on the determination of the maximum number of fiber Bragg gratings on one optical fiber using wavelength and time division multiplexing. In this paper, these techniques will be extended to determine the spectral width of wavelength division multiplexing in terms of the spectral width of the light emitting diode, the spectral width of the Bragg gratings, the measurement ranges of the individual sensors, and the guard band between two adjacent Bragg gratings. For time division multiplexing, a description of the time and power conditions are given. In particular the reflected power, first order crosstalk and chromatic dispersion have been considered. Finally, these relationships were applied to verify a design in a simulation using OptiSystem software.

Fusion safety codes International modeling with MELCOR and ATHENA- INTRA

CERN Document Server

Marshall, T; Topilski, L; Merrill, B

2002-01-01

For a number of years, the world fusion safety community has been involved in benchmarking their safety analyses codes against experiment data to support regulatory approval of a next step fusion device. This paper discusses the benchmarking of two prominent fusion safety thermal-hydraulic computer codes. The MELCOR code was developed in the US for fission severe accident safety analyses and has been modified for fusion safety analyses. The ATHENA code is a multifluid version of the US-developed RELAP5 code that is also widely used for fusion safety analyses. The ENEA Fusion Division uses ATHENA in conjunction with the INTRA code for its safety analyses. The INTRA code was developed in Germany and predicts containment building pressures, temperatures and fluid flow. ENEA employs the French-developed ISAS system to couple ATHENA and INTRA. This paper provides a brief introduction of the MELCOR and ATHENA-INTRA codes and presents their modeling results for the following breaches of a water cooling line into the...

Progress report of Technical Physics Division: April 1980 - March 1982

International Nuclear Information System (INIS)

Chaudhry, Ramesh; Vijendran, P.

1983-01-01

Activities, with an individual summary of each, of the Technical Physics Division (TPD) of the Bhabha Atomic Research Centre (BARC), Bombay are reported for the period April 1980 - March 1982. The major thrust of the TPD's work has been in: (i) design and fabrication of instruments, devices and equipment and (ii) development of techniques in the frontline research and technology areas like vacuum science, surface analysis, cryogenics and crystal growing. The Division also provided custombuilt electronics equipment, vacuum systems and glass components and devices to the various Divisions of BARC and other units of the DAE. Training and manpower development activities and technology transfer activities are also reported. Lists of seminars, colloquia, publications during the period of the report are given. (M.G.B.)

Translation of ARAC computer codes

International Nuclear Information System (INIS)

Takahashi, Kunio; Chino, Masamichi; Honma, Toshimitsu; Ishikawa, Hirohiko; Kai, Michiaki; Imai, Kazuhiko; Asai, Kiyoshi

1982-05-01

In 1981 we have translated the famous MATHEW, ADPIC and their auxiliary computer codes for CDC 7600 computer version to FACOM M-200's. The codes consist of a part of the Atmospheric Release Advisory Capability (ARAC) system of Lawrence Livermore National Laboratory (LLNL). The MATHEW is a code for three-dimensional wind field analysis. Using observed data, it calculates the mass-consistent wind field of grid cells by a variational method. The ADPIC is a code for three-dimensional concentration prediction of gases and particulates released to the atmosphere. It calculates concentrations in grid cells by the particle-in-cell method. They are written in LLLTRAN, i.e., LLNL Fortran language and are implemented on the CDC 7600 computers of LLNL. In this report, i) the computational methods of the MATHEW/ADPIC and their auxiliary codes, ii) comparisons of the calculated results with our JAERI particle-in-cell, and gaussian plume models, iii) translation procedures from the CDC version to FACOM M-200's, are described. Under the permission of LLNL G-Division, this report is published to keep the track of the translation procedures and to serve our JAERI researchers for comparisons and references of their works. (author)

Code development for analysis of MHD pressure drop reduction in a liquid metal blanket using insulation technique based on a fully developed flow model

International Nuclear Information System (INIS)

Smolentsev, Sergey; Morley, Neil; Abdou, Mohamed

2005-01-01

The paper presents details of a new numerical code for analysis of a fully developed MHD flow in a channel of a liquid metal blanket using various insulation techniques. The code has specially been designed for channels with a 'sandwich' structure of several materials with different physical properties. The code includes a finite-volume formulation, automatically generated Hartmann number sensitive meshes, and effective convergence acceleration technique. Tests performed at Ha ∼ 10 4 have showed very good accuracy. As an illustration, two blanket flows have been considered: Pb-17Li flow in a channel with a silicon carbide flow channel insert, and Li flow in a channel with insulating coating

Rate-Compatible LDPC Codes with Linear Minimum Distance

Science.gov (United States)

Divsalar, Dariush; Jones, Christopher; Dolinar, Samuel

2009-01-01

A recently developed method of constructing protograph-based low-density parity-check (LDPC) codes provides for low iterative decoding thresholds and minimum distances proportional to block sizes, and can be used for various code rates. A code constructed by this method can have either fixed input block size or fixed output block size and, in either case, provides rate compatibility. The method comprises two submethods: one for fixed input block size and one for fixed output block size. The first mentioned submethod is useful for applications in which there are requirements for rate-compatible codes that have fixed input block sizes. These are codes in which only the numbers of parity bits are allowed to vary. The fixed-output-blocksize submethod is useful for applications in which framing constraints are imposed on the physical layers of affected communication systems. An example of such a system is one that conforms to one of many new wireless-communication standards that involve the use of orthogonal frequency-division modulation

Orthogonal frequency division multiple access fundamentals and applications

CERN Document Server

Jiang, Tao; Zhang, Yan

2010-01-01

Supported by the expert-level advice of pioneering researchers, Orthogonal Frequency Division Multiple Access Fundamentals and Applications provides a comprehensive and accessible introduction to the foundations and applications of one of the most promising access technologies for current and future wireless networks. It includes authoritative coverage of the history, fundamental principles, key techniques, and critical design issues of OFDM systems. Covering various techniques of effective resource management for OFDM/OFDMA-based wireless communication systems, this cutting-edge reference:Add

A polarization-division multiplexing SSB-OFDM system with beat interference cancellation receivers

Science.gov (United States)

Yang, Peiling; Ma, Jianxin; Zhang, Junyi

2018-06-01

In this paper, we have proposed a polarization-division multiplexing (PDM) single-sideband optical orthogonal frequency division multiplexing (SSB-OOFDM) scheme with signal-signal beat interference cancellation receivers with balanced detection (ICRBD). This system can double channel capacity and improve spectrum efficiency (SE) with the reduced guard band (GB) due to the PDM. Multiple input multiple output (MIMO) technique is used to solve polarization mode dispersion (PMD) associated with channel estimation and equalization. By simulation, we demonstrate the efficacy of the proposed technique for a 2 ×40 Gbit/s 16-QAM SSB-PDM-OOFDM system according to the error vector magnitude (EVM) and the constellation diagrams.

Radiochemistry Division: annual progress report: 1987

International Nuclear Information System (INIS)

1989-01-01

The progress of Research and Development (R and D) activities during the year 1987 are reported in the form of summaries, which are presented under the headings (1) Actinide Chemistry, (2) Nuclear Chemistry, and (3) Spectroscopy. Microwave absorption studies of the high Tsub(c) oxide superconductor YBa 2 Cu 3 Osub(7-x) using electron paramagnetic resonance techniques are the new feature during the report year. Radioanalytical services and radiation sources in the form of electrodeposited sources or standard soluti ons were also given to the other Divisions, other units of the Department of Atomic Energy, and other organisations in the country. A list of papers by the members of the Division published in various journals and presented at various symposia, conferences etc. is given at the end of the report. (M.G.B.). refs., 51 tabs., 33 figs

Some new classes of division algebras and potential applications to space-time block coding

OpenAIRE

Steele, Andrew

2014-01-01

In this thesis we study some new classes of nonassociative division algebras. First we introduce a generalisation of both associative cyclic algebras and of Waterhouse's nonassociative quaternions. An important aspect of these algebras is the simplicity of their construction, which is a modification of the classical definition of associative cyclic algebras. By taking the parameter used in the classical definition from a larger field, we lose the property of associativity but gain many new ex...

Parallelization of quantum molecular dynamics simulation code

International Nuclear Information System (INIS)

Kato, Kaori; Kunugi, Tomoaki; Shibahara, Masahiko; Kotake, Susumu

1998-02-01

A quantum molecular dynamics simulation code has been developed for the analysis of the thermalization of photon energies in the molecule or materials in Kansai Research Establishment. The simulation code is parallelized for both Scalar massively parallel computer (Intel Paragon XP/S75) and Vector parallel computer (Fujitsu VPP300/12). Scalable speed-up has been obtained with a distribution to processor units by division of particle group in both parallel computers. As a result of distribution to processor units not only by particle group but also by the particles calculation that is constructed with fine calculations, highly parallelization performance is achieved in Intel Paragon XP/S75. (author)

Library system for a one dimensional tokamak transport code: (LIBJT60), 1

International Nuclear Information System (INIS)

Hirayama, Toshio

1982-12-01

A library system is developed to control and manage huge programs in terms of FORTRAN source. It is applied to widely used one dimensional tokamak transport codes (LIBJT60), which have been developed in the Division of Large Tokamak Development. The structure of data and program in the transport code turn out to be flexible enough to respond to various demands and this gigantic code frame work can be decomposed into groups of a compact code with a specific function. Some editing support tools for programming and debugging are also developed to save programming work. By applying this library system, users can obtain a code whose functions can be efficiently developed. (author)

Coding Across Multicodes and Time in CDMA Systems Employing MMSE Multiuser Detector

Directory of Open Access Journals (Sweden)

Park Jeongsoon

2004-01-01

Full Text Available When combining a multicode CDMA system with convolutional coding, two methods have been considered in the literature. In one method, coding is across time in each multicode channel while in the other the coding is across both multicodes and time. In this paper, a performance/complexity analysis of decoding metrics and trellis structures for the two schemes is carried out. It is shown that the latter scheme can exploit the multicode diversity inherent in convolutionally coded direct sequence code division multiple access (DS-CDMA systems which employ minimum mean squared error (MMSE multiuser detectors. In particular, when the MMSE detector provides sufficiently different signal-to-interference ratios (SIRs for the multicode channels, coding across multicodes and time can obtain significant performance gain over coding across time, with nearly the same decoding complexity.

Signalign: An Ontology of DNA as Signal for Comparative Gene Structure Prediction Using Information-Coding-and-Processing Techniques.

Science.gov (United States)

Yu, Ning; Guo, Xuan; Gu, Feng; Pan, Yi

2016-03-01

Conventional character-analysis-based techniques in genome analysis manifest three main shortcomings-inefficiency, inflexibility, and incompatibility. In our previous research, a general framework, called DNA As X was proposed for character-analysis-free techniques to overcome these shortcomings, where X is the intermediates, such as digit, code, signal, vector, tree, graph network, and so on. In this paper, we further implement an ontology of DNA As Signal, by designing a tool named Signalign for comparative gene structure analysis, in which DNA sequences are converted into signal series, processed by modified method of dynamic time warping and measured by signal-to-noise ratio (SNR). The ontology of DNA As Signal integrates the principles and concepts of other disciplines including information coding theory and signal processing into sequence analysis and processing. Comparing with conventional character-analysis-based methods, Signalign can not only have the equivalent or superior performance, but also enrich the tools and the knowledge library of computational biology by extending the domain from character/string to diverse areas. The evaluation results validate the success of the character-analysis-free technique for improved performances in comparative gene structure prediction.

Annual report of the Nuclear Physics Division [for] period ending December 31, 1976

International Nuclear Information System (INIS)

Thaper, C.L.; Ajitanand, N.N.; Kailas, S.

1978-01-01

The research and development (R and D) activities of the Nuclear Physics Division of the Bhabha Atomic Research Centre, Bombay, during the calendar year 1976 are reported. The R and D activities of the Division cover the areas of nuclear physics, fission physics and solid state physics. Various experimental techniques and instruments developed are also briefly described. (M.G.B.)

Speech coding

Energy Technology Data Exchange (ETDEWEB)

Ravishankar, C., Hughes Network Systems, Germantown, MD

1998-05-08

Speech is the predominant means of communication between human beings and since the invention of the telephone by Alexander Graham Bell in 1876, speech services have remained to be the core service in almost all telecommunication systems. Original analog methods of telephony had the disadvantage of speech signal getting corrupted by noise, cross-talk and distortion Long haul transmissions which use repeaters to compensate for the loss in signal strength on transmission links also increase the associated noise and distortion. On the other hand digital transmission is relatively immune to noise, cross-talk and distortion primarily because of the capability to faithfully regenerate digital signal at each repeater purely based on a binary decision. Hence end-to-end performance of the digital link essentially becomes independent of the length and operating frequency bands of the link Hence from a transmission point of view digital transmission has been the preferred approach due to its higher immunity to noise. The need to carry digital speech became extremely important from a service provision point of view as well. Modem requirements have introduced the need for robust, flexible and secure services that can carry a multitude of signal types (such as voice, data and video) without a fundamental change in infrastructure. Such a requirement could not have been easily met without the advent of digital transmission systems, thereby requiring speech to be coded digitally. The term Speech Coding is often referred to techniques that represent or code speech signals either directly as a waveform or as a set of parameters by analyzing the speech signal. In either case, the codes are transmitted to the distant end where speech is reconstructed or synthesized using the received set of codes. A more generic term that is applicable to these techniques that is often interchangeably used with speech coding is the term voice coding. This term is more generic in the sense that the

Westinghouse Water Reactor Divisions quality assurance plan

International Nuclear Information System (INIS)

1977-09-01

The Quality Assurance Program used by Westinghouse Water Reactor Divisions is described. The purpose of the program is to assure that the design, materials, and workmanship on Nuclear Steam Supply System (NSSS) equipment meet applicable safety requirements, fulfill the requirements of the contracts with the applicants, and satisfy the applicable codes, standards, and regulatory requirements. This program satisfies the NRC Quality Assurance Criteria, 10CFR50 Appendix B, to the extent that these criteria apply to safety related NSSS equipment. Also, it follows the regulatory position provided in NRC regulatory guides and the requirements of ANSI Standard N45.2.12 as identified in this Topical Report

Efficient coding schemes with power allocation using space-time-frequency spreading

Institute of Scientific and Technical Information of China (English)

Jiang Haining; Luo Hanwen; Tian Jifeng; Song Wentao; Liu Xingzhao

2006-01-01

An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MIMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.

A hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks.

Science.gov (United States)

Choi, Yong-Kyu; Hosoya, Kenta; Lee, Chung Ghiu; Hanawa, Masanori; Park, Chang-Soo

2011-03-28

We propose and experimentally demonstrate a hybrid WDM/OCDMA ring with a dynamic add/drop function based on Fourier code for local area networks. Dynamic function is implemented by mechanically tuning the Fourier encoder/decoder for optical code division multiple access (OCDMA) encoding/decoding. Wavelength division multiplexing (WDM) is utilized for node assignment and 4-chip Fourier code recovers the matched signal from the codes. For an optical source well adapted to WDM channels and its short optical pulse generation, reflective semiconductor optical amplifiers (RSOAs) are used with a fiber Bragg grating (FBG) and gain-switched. To demonstrate we experimentally investigated a two-node hybrid WDM/OCDMA ring with a 4-chip Fourier encoder/decoder fabricated by cascading four FBGs with the bit error rate (BER) of <10(-9) for the node span of 10.64 km at 1.25 Gb/s.

Division of Radiological Protection progress report 1982-1988

International Nuclear Information System (INIS)

Gupta, B.L.; Bhat, R.M.; Narayan, G.R.

1989-01-01

This report describes the work of the Division of Radiological Protection during 2-88, for implementation of radiation safety in all institutions in the country using radiation sources for medical, industrial and research applications. It gives information about personnel monitoring using photographic film and TLD badges, neutron monitoring badges, dosimetric techniques developed, calibration facilities and maintenance of national standards for radiation and radioactivity, design and fabrication of special radiation protection instruments, development of coloured indicators for indentification of radiation sterilized medical products, advisory and licencing services, regulation and transport of radioactive materials, periodic protection survey, education and training related to radiation safety programmes. About 500 publications by the staff of this Division are listed. (author). 46 figs

Computational Fair Division

DEFF Research Database (Denmark)

Branzei, Simina

Fair division is a fundamental problem in economic theory and one of the oldest questions faced through the history of human society. The high level scenario is that of several participants having to divide a collection of resources such that everyone is satisfied with their allocation -- e.g. two...... heirs dividing a car, house, and piece of land inherited. The literature on fair division was developed in the 20th century in mathematics and economics, but computational work on fair division is still sparse. This thesis can be seen as an excursion in computational fair division divided in two parts....... The first part tackles the cake cutting problem, where the cake is a metaphor for a heterogeneous divisible resource such as land, time, mineral deposits, and computer memory. We study the equilibria of classical protocols and design an algorithmic framework for reasoning about their game theoretic...

Adaptive distributed source coding.

Science.gov (United States)

Varodayan, David; Lin, Yao-Chung; Girod, Bernd

2012-05-01

We consider distributed source coding in the presence of hidden variables that parameterize the statistical dependence among sources. We derive the Slepian-Wolf bound and devise coding algorithms for a block-candidate model of this problem. The encoder sends, in addition to syndrome bits, a portion of the source to the decoder uncoded as doping bits. The decoder uses the sum-product algorithm to simultaneously recover the source symbols and the hidden statistical dependence variables. We also develop novel techniques based on density evolution (DE) to analyze the coding algorithms. We experimentally confirm that our DE analysis closely approximates practical performance. This result allows us to efficiently optimize parameters of the algorithms. In particular, we show that the system performs close to the Slepian-Wolf bound when an appropriate doping rate is selected. We then apply our coding and analysis techniques to a reduced-reference video quality monitoring system and show a bit rate saving of about 75% compared with fixed-length coding.

Specialized Monte Carlo codes versus general-purpose Monte Carlo codes

International Nuclear Information System (INIS)

Moskvin, Vadim; DesRosiers, Colleen; Papiez, Lech; Lu, Xiaoyi

2002-01-01

The possibilities of Monte Carlo modeling for dose calculations and optimization treatment are quite limited in radiation oncology applications. The main reason is that the Monte Carlo technique for dose calculations is time consuming while treatment planning may require hundreds of possible cases of dose simulations to be evaluated for dose optimization. The second reason is that general-purpose codes widely used in practice, require an experienced user to customize them for calculations. This paper discusses the concept of Monte Carlo code design that can avoid the main problems that are preventing wide spread use of this simulation technique in medical physics. (authors)

15 years in promoting the use of isotopic and nuclear technique for combating land degradation and soil erosion: the contribution of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture

Science.gov (United States)

Mabit, Lionel; Toloza, Arsenio; Heng, Lee

2017-04-01

Techniques in Food and Agriculture has developed research and development activities and capacity building to combat soil degradation (especially soil erosion) and to foster climate smart agriculture. More than 70 FAO/IAEA Member States have benefitted from the technical support and guidance in using fallout radionuclides (FRNs) and Compound-Specific Stable Isotope (CSSI) techniques to trace soil movement and assess soil erosion at different spatial and temporal scales, and to evaluate the effectiveness of soil conservation strategies to ensure sustainable land management. This contribution summarizes the historical background and the latest innovative activities conducted by the Joint FAO/IAEA Division, as well as the main advantages and complementarity of stable and radioisotopic tracers to conventional techniques when investigating land degradation. As examples of the significant role played by the Joint FAO/IAEA Division, two major outcomes achieved in Africa (i.e. Madagascar and Morocco) through the use of isotopic and nuclear techniques will be elaborated. The authors will also report on a new 5-year Co-ordinated Research Project (CRP) funded by the IAEA on "Nuclear Techniques for a Better Understanding of the Impact of Climate Change on Soil Erosion in Upland Agro-ecosystems" which involves key research institutions from 12 participating countries.

On infinitely divisible semimartingales

DEFF Research Database (Denmark)

Basse-O'Connor, Andreas; Rosiński, Jan

2015-01-01

to non Gaussian infinitely divisible processes. First we show that the class of infinitely divisible semimartingales is so large that the natural analog of Stricker's theorem fails to hold. Then, as the main result, we prove that an infinitely divisible semimartingale relative to the filtration generated...... by a random measure admits a unique decomposition into an independent increment process and an infinitely divisible process of finite variation. Consequently, the natural analog of Stricker's theorem holds for all strictly representable processes (as defined in this paper). Since Gaussian processes...... are strictly representable due to Hida's multiplicity theorem, the classical Stricker's theorem follows from our result. Another consequence is that the question when an infinitely divisible process is a semimartingale can often be reduced to a path property, when a certain associated infinitely divisible...

2x2 MIMO-OFDM Gigabit fiber-wireless access system based on polarization division multiplexed WDM-PON

DEFF Research Database (Denmark)

Deng, Lei; Pang, Xiaodan; Zhao, Ying

2012-01-01

We propose a spectral efficient radio over wavelength division multiplexed passive optical network (WDM-PON) system by combining optical polarization division multiplexing (PDM) and wireless multiple input multiple output (MIMO) spatial multiplexing techniques. In our experiment, a training-based...

Optical coding theory with Prime

CERN Document Server

Kwong, Wing C

2013-01-01

Although several books cover the coding theory of wireless communications and the hardware technologies and coding techniques of optical CDMA, no book has been specifically dedicated to optical coding theory-until now. Written by renowned authorities in the field, Optical Coding Theory with Prime gathers together in one volume the fundamentals and developments of optical coding theory, with a focus on families of prime codes, supplemented with several families of non-prime codes. The book also explores potential applications to coding-based optical systems and networks. Learn How to Construct

Vector Quantization of Harmonic Magnitudes in Speech Coding Applications—A Survey and New Technique

Directory of Open Access Journals (Sweden)

Wai C. Chu

2004-12-01

Full Text Available A harmonic coder extracts the harmonic components of a signal and represents them efficiently using a few parameters. The principles of harmonic coding have become quite successful and several standardized speech and audio coders are based on it. One of the key issues in harmonic coder design is in the quantization of harmonic magnitudes, where many propositions have appeared in the literature. The objective of this paper is to provide a survey of the various techniques that have appeared in the literature for vector quantization of harmonic magnitudes, with emphasis on those adopted by the major speech coding standards; these include constant magnitude approximation, partial quantization, dimension conversion, and variable-dimension vector quantization (VDVQ. In addition, a refined VDVQ technique is proposed where experimental data are provided to demonstrate its effectiveness.

Interference Cancellation Technique Based on Discovery of Spreading Codes of Interference Signals and Maximum Correlation Detection for DS-CDMA System

Science.gov (United States)

Hettiarachchi, Ranga; Yokoyama, Mitsuo; Uehara, Hideyuki

This paper presents a novel interference cancellation (IC) scheme for both synchronous and asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless channels. In the DS-CDMA system, the multiple access interference (MAI) and the near-far problem (NFP) are the two factors which reduce the capacity of the system. In this paper, we propose a new algorithm that is able to detect all interference signals as an individual MAI signal by maximum correlation detection. It is based on the discovery of all the unknowing spreading codes of the interference signals. Then, all possible MAI patterns so called replicas are generated as a summation of interference signals. And the true MAI pattern is found by taking correlation between the received signal and the replicas. Moreover, the receiver executes MAI cancellation in a successive manner, removing all interference signals by single-stage. Numerical results will show that the proposed IC strategy, which alleviates the detrimental effect of the MAI and the near-far problem, can significantly improve the system performance. Especially, we can obtain almost the same receiving characteristics as in the absense of interference for asynchrnous system when received powers are equal. Also, the same performances can be seen under any received power state for synchronous system.

A computer code to simulate X-ray imaging techniques

International Nuclear Information System (INIS)

Duvauchelle, Philippe; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

2000-01-01

A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests

A computer code to simulate X-ray imaging techniques

Energy Technology Data Exchange (ETDEWEB)

Duvauchelle, Philippe E-mail: philippe.duvauchelle@insa-lyon.fr; Freud, Nicolas; Kaftandjian, Valerie; Babot, Daniel

2000-09-01

A computer code was developed to simulate the operation of radiographic, radioscopic or tomographic devices. The simulation is based on ray-tracing techniques and on the X-ray attenuation law. The use of computer-aided drawing (CAD) models enables simulations to be carried out with complex three-dimensional (3D) objects and the geometry of every component of the imaging chain, from the source to the detector, can be defined. Geometric unsharpness, for example, can be easily taken into account, even in complex configurations. Automatic translations or rotations of the object can be performed to simulate radioscopic or tomographic image acquisition. Simulations can be carried out with monochromatic or polychromatic beam spectra. This feature enables, for example, the beam hardening phenomenon to be dealt with or dual energy imaging techniques to be studied. The simulation principle is completely deterministic and consequently the computed images present no photon noise. Nevertheless, the variance of the signal associated with each pixel of the detector can be determined, which enables contrast-to-noise ratio (CNR) maps to be computed, in order to predict quantitatively the detectability of defects in the inspected object. The CNR is a relevant indicator for optimizing the experimental parameters. This paper provides several examples of simulated images that illustrate some of the rich possibilities offered by our software. Depending on the simulation type, the computation time order of magnitude can vary from 0.1 s (simple radiographic projection) up to several hours (3D tomography) on a PC, with a 400 MHz microprocessor. Our simulation tool proves to be useful in developing new specific applications, in choosing the most suitable components when designing a new testing chain, and in saving time by reducing the number of experimental tests.

Codes and curves

CERN Document Server

Walker, Judy L

2000-01-01

When information is transmitted, errors are likely to occur. Coding theory examines efficient ways of packaging data so that these errors can be detected, or even corrected. The traditional tools of coding theory have come from combinatorics and group theory. Lately, however, coding theorists have added techniques from algebraic geometry to their toolboxes. In particular, by re-interpreting the Reed-Solomon codes, one can see how to define new codes based on divisors on algebraic curves. For instance, using modular curves over finite fields, Tsfasman, Vladut, and Zink showed that one can define a sequence of codes with asymptotically better parameters than any previously known codes. This monograph is based on a series of lectures the author gave as part of the IAS/PCMI program on arithmetic algebraic geometry. Here, the reader is introduced to the exciting field of algebraic geometric coding theory. Presenting the material in the same conversational tone of the lectures, the author covers linear codes, inclu...

Inclusion of the fitness sharing technique in an evolutionary algorithm to analyze the fitness landscape of the genetic code adaptability.

Science.gov (United States)

Santos, José; Monteagudo, Ángel

2017-03-27

The canonical code, although prevailing in complex genomes, is not universal. It was shown the canonical genetic code superior robustness compared to random codes, but it is not clearly determined how it evolved towards its current form. The error minimization theory considers the minimization of point mutation adverse effect as the main selection factor in the evolution of the code. We have used simulated evolution in a computer to search for optimized codes, which helps to obtain information about the optimization level of the canonical code in its evolution. A genetic algorithm searches for efficient codes in a fitness landscape that corresponds with the adaptability of possible hypothetical genetic codes. The lower the effects of errors or mutations in the codon bases of a hypothetical code, the more efficient or optimal is that code. The inclusion of the fitness sharing technique in the evolutionary algorithm allows the extent to which the canonical genetic code is in an area corresponding to a deep local minimum to be easily determined, even in the high dimensional spaces considered. The analyses show that the canonical code is not in a deep local minimum and that the fitness landscape is not a multimodal fitness landscape with deep and separated peaks. Moreover, the canonical code is clearly far away from the areas of higher fitness in the landscape. Given the non-presence of deep local minima in the landscape, although the code could evolve and different forces could shape its structure, the fitness landscape nature considered in the error minimization theory does not explain why the canonical code ended its evolution in a location which is not an area of a localized deep minimum of the huge fitness landscape.

Art of persuasion: an analysis of techniques used to market foods to children.

Science.gov (United States)

Hebden, Lana; King, Lesley; Kelly, Bridget

2011-11-01

Persuasive marketing techniques, such as promotional characters, influence children's food preferences and requests for foods. The aim of this research was to describe the techniques used to market unhealthy foods and beverages to children on Sydney free-to-air television. Marketing techniques designed to appeal to children were identified from international literature and summarised into a systematic coding tool. Using this tool, the marketing techniques used in a random sample of 100 unique food advertisements, broadcasted on Sydney free-to-air television, were coded. Frequency of marketing techniques was analysed overall and for use in advertisements marketing unhealthy foods, emotionally or verbally appealing to parents, or featuring child actors. Advertisers' use of persuasive techniques generally did not differ by type of food advertised. Marketing techniques with greater prominence in unhealthy food advertising were palatability (54% of unhealthy food advertisements), convenience (52%), fantasy/imagination (28%), fun/happiness (17%) and cartoon characters (9%). Advertisements emotionally appealing to parents (24%) were significantly more likely to make general health or nutrition statements (38% vs. 17%), and appealed to children concurrently through fun/happiness and fantasy/imagination appeals. Children were depicted in advertisements as eating with friends or family, situated within the home and frequently snacking on less healthy foods. Food and beverage advertisers use a range of visual, audio and emotive techniques to appeal to children and their parents that do not discriminate by the type of food advertised. The range and complexity of these techniques complicate the restriction of their use in food advertising to children. © 2011 The Authors. Journal of Paediatrics and Child Health © 2011 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

Estimation of small perturbation effects in multiversion calculations by the PRIZMA-D code

International Nuclear Information System (INIS)

Kandiev, Ya.Z.; Malakhov, A.A.; Serova, E.V.; Spirina, S.G.

2005-01-01

The PRIZMA-D code is intended for solving by the Monte Carlo method of the problems, connected with calculations of nuclear reactors and critical assemblies. Taking into account the effect of the perturbation on the distribution of the source division points is carried out by means of the method of small iterations for the division points. This method is described in the paper. Possibilities of its application are shown by the examples of calculations of some problems. The comparative results are presented [ru

Phase division multiplexed EIT for enhanced temporal resolution.

Science.gov (United States)

Dowrick, T; Holder, D

2018-03-29

The most commonly used EIT paradigm (time division multiplexing) limits the temporal resolution of impedance images due to the need to switch between injection electrodes. Advances have previously been made using frequency division multiplexing (FDM) to increase temporal resolution, but in cases where a fixed range of frequencies is available, such as imaging fast neural activity, an upper limit is placed on the total number of simultaneous injections. The use of phase division multiplexing (PDM) where multiple out of phase signals can be injected at each frequency is investigated to increase temporal resolution. TDM, FDM and PDM were compared in head tank experiments, to compare transfer impedance measurements and spatial resolution between the three techniques. A resistor phantom paradigm was established to investigate the imaging of one-off impedance changes, of magnitude 1% and with durations as low as 500 µs (similar to those seen in nerve bundles), using both PDM and TDM approaches. In head tank experiments, a strong correlation (r  >  0.85 and p  EIT injections.

Error-correction coding and decoding bounds, codes, decoders, analysis and applications

CERN Document Server

Tomlinson, Martin; Ambroze, Marcel A; Ahmed, Mohammed; Jibril, Mubarak

2017-01-01

This book discusses both the theory and practical applications of self-correcting data, commonly known as error-correcting codes. The applications included demonstrate the importance of these codes in a wide range of everyday technologies, from smartphones to secure communications and transactions. Written in a readily understandable style, the book presents the authors’ twenty-five years of research organized into five parts: Part I is concerned with the theoretical performance attainable by using error correcting codes to achieve communications efficiency in digital communications systems. Part II explores the construction of error-correcting codes and explains the different families of codes and how they are designed. Techniques are described for producing the very best codes. Part III addresses the analysis of low-density parity-check (LDPC) codes, primarily to calculate their stopping sets and low-weight codeword spectrum which determines the performance of these codes. Part IV deals with decoders desi...

Construction and performance research on variable-length codes for multirate OCDMA multimedia networks

Science.gov (United States)

Li, Chuan-qi; Yang, Meng-jie; Luo, De-jun; Lu, Ye; Kong, Yi-pu; Zhang, Dong-chuang

2014-09-01

A new kind of variable-length codes with good correlation properties for the multirate asynchronous optical code division multiple access (OCDMA) multimedia networks is proposed, called non-repetition interval (NRI) codes. The NRI codes can be constructed by structuring the interval-sets with no repetition, and the code length depends on the number of users and the code weight. According to the structural characteristics of NRI codes, the formula of bit error rate (BER) is derived. Compared with other variable-length codes, the NRI codes have lower BER. A multirate OCDMA multimedia simulation system is designed and built, the longer codes are assigned to the users who need slow speed, while the shorter codes are assigned to the users who need high speed. It can be obtained by analyzing the eye diagram that the user with slower speed has lower BER, and the conclusion is the same as the actual demand in multimedia data transport.

Coded Aperture Nuclear Scintigraphy: A Novel Small Animal Imaging Technique

Directory of Open Access Journals (Sweden)

Dawid Schellingerhout

2002-10-01

Full Text Available We introduce and demonstrate the utility of coded aperture (CA nuclear scintigraphy for imaging small animals. CA imaging uses multiple pinholes in a carefully designed mask pattern, mounted on a conventional gamma camera. System performance was assessed using point sources and phantoms, while several animal experiments were performed to test the usefulness of the imaging system in vivo, with commonly used radiopharmaceuticals. The sensitivity of the CA system for 99mTc was 4.2 × 103 cps/Bq (9400 cpm/μCi, compared to 4.4 × 104 cps/Bq (990 cpm/μCi for a conventional collimator system. The system resolution was 1.7 mm, as compared to 4–6 mm for the conventional imaging system (using a high-sensitivity low-energy collimator. Animal imaging demonstrated artifact-free imaging with superior resolution and image quality compared to conventional collimator images in several mouse and rat models. We conclude that: (a CA imaging is a useful nuclear imaging technique for small animal imaging. The advantage in signal-to-noise can be traded to achieve higher resolution, decreased dose or reduced imaging time. (b CA imaging works best for images where activity is concentrated in small volumes; a low count outline may be better demonstrated using conventional collimator imaging. Thus, CA imaging should be viewed as a technique to complement rather than replace traditional nuclear imaging methods. (c CA hardware and software can be readily adapted to existing gamma cameras, making their implementation a relatively inexpensive retrofit to most systems.

Solid State Division progress report for period ending September 30, 1993

Energy Technology Data Exchange (ETDEWEB)

Green, P.H.; Hinton, L.W. [eds.

1994-08-01

This report covers research progress in the Solid State Division from April 1, 1992, to September 30, 1993. During this period, the division conducted a broad, interdisciplinary materials research program with emphasis on theoretical solid state physics, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. This research effort was enhanced by new capabilities in atomic-scale materials characterization, new emphasis on the synthesis and processing of materials, and increased partnering with industry and universities. The theoretical effort included a broad range of analytical studies, as well as a new emphasis on numerical simulation stimulated by advances in high-performance computing and by strong interest in related division experimental programs. Superconductivity research continued to advance on a broad front from fundamental mechanisms of high-temperature superconductivity to the development of new materials and processing techniques. The Neutron Scattering Program was characterized by a strong scientific user program and growing diversity represented by new initiatives in complex fluids and residual stress. The national emphasis on materials synthesis and processing was mirrored in division research programs in thin-film processing, surface modification, and crystal growth. Research on advanced processing techniques such as laser ablation, ion implantation, and plasma processing was complemented by strong programs in the characterization of materials and surfaces including ultrahigh resolution scanning transmission electron microscopy, atomic-resolution chemical analysis, synchrotron x-ray research, and scanning tunneling microscopy.

Solid State Division progress report for period ending September 30, 1993

International Nuclear Information System (INIS)

Green, P.H.; Hinton, L.W.

1994-08-01

This report covers research progress in the Solid State Division from April 1, 1992, to September 30, 1993. During this period, the division conducted a broad, interdisciplinary materials research program with emphasis on theoretical solid state physics, neutron scattering, synthesis and characterization of materials, ion beam and laser processing, and the structure of solids and surfaces. This research effort was enhanced by new capabilities in atomic-scale materials characterization, new emphasis on the synthesis and processing of materials, and increased partnering with industry and universities. The theoretical effort included a broad range of analytical studies, as well as a new emphasis on numerical simulation stimulated by advances in high-performance computing and by strong interest in related division experimental programs. Superconductivity research continued to advance on a broad front from fundamental mechanisms of high-temperature superconductivity to the development of new materials and processing techniques. The Neutron Scattering Program was characterized by a strong scientific user program and growing diversity represented by new initiatives in complex fluids and residual stress. The national emphasis on materials synthesis and processing was mirrored in division research programs in thin-film processing, surface modification, and crystal growth. Research on advanced processing techniques such as laser ablation, ion implantation, and plasma processing was complemented by strong programs in the characterization of materials and surfaces including ultrahigh resolution scanning transmission electron microscopy, atomic-resolution chemical analysis, synchrotron x-ray research, and scanning tunneling microscopy

Fusion Energy Division progress report, 1 January 1990--31 December 1991

Energy Technology Data Exchange (ETDEWEB)

Sheffield, J.; Baker, C.C.; Saltmarsh, M.J.

1994-03-01

The Fusion Program of the Oak Ridge National Laboratory (ORNL), a major part of the national fusion program, encompasses nearly all areas of magnetic fusion research. The program is directed toward the development of fusion as an economical and environmentally attractive energy source for the future. The program involves staff from ORNL, Martin Marietta Energy systems, Inc., private industry, the academic community, and other fusion laboratories, in the US and abroad. Achievements resulting from this collaboration are documented in this report, which is issued as the progress report of the ORNL Fusion Energy Division; it also contains information from components for the Fusion Program that are external to the division (about 15% of the program effort). The areas addressed by the Fusion Program include the following: experimental and theoretical research on magnetic confinement concepts; engineering and physics of existing and planned devices, including remote handling; development and testing of diagnostic tools and techniques in support of experiments; assembly and distribution to the fusion community of databases on atomic physics and radiation effects; development and testing of technologies for heating and fueling fusion plasmas; development and testing of superconducting magnets for containing fusion plasmas; development and testing of materials for fusion devices; and exploration of opportunities to apply the unique skills, technology, and techniques developed in the course of this work to other areas (about 15% of the Division`s activities). Highlights from program activities during 1990 and 1991 are presented.

Cell Division Synchronization

Science.gov (United States)

The report summarizes the progress in the design and construction of automatic equipment for synchronizing cell division in culture by periodic...Concurrent experiments in hypothermic synchronization of algal cell division are reported.

Stylize Aesthetic QR Code

OpenAIRE

Xu, Mingliang; Su, Hao; Li, Yafei; Li, Xi; Liao, Jing; Niu, Jianwei; Lv, Pei; Zhou, Bing

2018-01-01

With the continued proliferation of smart mobile devices, Quick Response (QR) code has become one of the most-used types of two-dimensional code in the world. Aiming at beautifying the appearance of QR codes, existing works have developed a series of techniques to make the QR code more visual-pleasant. However, these works still leave much to be desired, such as visual diversity, aesthetic quality, flexibility, universal property, and robustness. To address these issues, in this paper, we pro...

LDPC Codes--Structural Analysis and Decoding Techniques

Science.gov (United States)

Zhang, Xiaojie

2012-01-01

Low-density parity-check (LDPC) codes have been the focus of much research over the past decade thanks to their near Shannon limit performance and to their efficient message-passing (MP) decoding algorithms. However, the error floor phenomenon observed in MP decoding, which manifests itself as an abrupt change in the slope of the error-rate curve,…

Argonne Physics Division Colloquium

Science.gov (United States)

[Argonne Logo] [DOE Logo] Physics Division Home News Division Information Contact PHY Org Chart Physics Division Colloquium Auditorium, Building 203, Argonne National Laboratory Fridays at 11:00 AM 2017 : Sereres Johnston 15 Sep 2017 Joint Physics and Materials Science Colloquium J. C. Séamus Davis, Cornell

Advanced hardware design for error correcting codes

CERN Document Server

Coussy, Philippe

2015-01-01

This book provides thorough coverage of error correcting techniques. It includes essential basic concepts and the latest advances on key topics in design, implementation, and optimization of hardware/software systems for error correction. The book’s chapters are written by internationally recognized experts in this field. Topics include evolution of error correction techniques, industrial user needs, architectures, and design approaches for the most advanced error correcting codes (Polar Codes, Non-Binary LDPC, Product Codes, etc). This book provides access to recent results, and is suitable for graduate students and researchers of mathematics, computer science, and engineering. • Examines how to optimize the architecture of hardware design for error correcting codes; • Presents error correction codes from theory to optimized architecture for the current and the next generation standards; • Provides coverage of industrial user needs advanced error correcting techniques.

Opportunistic Adaptive Transmission for Network Coding Using Nonbinary LDPC Codes

Directory of Open Access Journals (Sweden)

Cocco Giuseppe

2010-01-01

Full Text Available Network coding allows to exploit spatial diversity naturally present in mobile wireless networks and can be seen as an example of cooperative communication at the link layer and above. Such promising technique needs to rely on a suitable physical layer in order to achieve its best performance. In this paper, we present an opportunistic packet scheduling method based on physical layer considerations. We extend channel adaptation proposed for the broadcast phase of asymmetric two-way bidirectional relaying to a generic number of sinks and apply it to a network context. The method consists of adapting the information rate for each receiving node according to its channel status and independently of the other nodes. In this way, a higher network throughput can be achieved at the expense of a slightly higher complexity at the transmitter. This configuration allows to perform rate adaptation while fully preserving the benefits of channel and network coding. We carry out an information theoretical analysis of such approach and of that typically used in network coding. Numerical results based on nonbinary LDPC codes confirm the effectiveness of our approach with respect to previously proposed opportunistic scheduling techniques.

Annual report of the Nuclear Physics Division [for] period ending December 31, 1982

International Nuclear Information System (INIS)

Eswaran, M.A.; Paranjpe, A.S.

1985-01-01

The research and development work of the Nuclear Physics Division of the Bhabha Atomic Research Centre, Bombay for the period ending on 31 December 1982 is reported in the form of individual summaries arranged under the headings: (1) nuclear physics, (2) solid state physics, and (3) instrumentation and techniques. A list of papers by the staff-members of the Division published in journals and presented at conferences during the report period is also given. (author)

Fracture flow code

International Nuclear Information System (INIS)

Dershowitz, W; Herbert, A.; Long, J.

1989-03-01

The hydrology of the SCV site will be modelled utilizing discrete fracture flow models. These models are complex, and can not be fully cerified by comparison to analytical solutions. The best approach for verification of these codes is therefore cross-verification between different codes. This is complicated by the variation in assumptions and solution techniques utilized in different codes. Cross-verification procedures are defined which allow comparison of the codes developed by Harwell Laboratory, Lawrence Berkeley Laboratory, and Golder Associates Inc. Six cross-verification datasets are defined for deterministic and stochastic verification of geometric and flow features of the codes. Additional datasets for verification of transport features will be documented in a future report. (13 figs., 7 tabs., 10 refs.) (authors)

MARS 1.3 system analysis code coupling with CONTEMPT4/MOD5/PCCS containment analysis code using dynamic link library

International Nuclear Information System (INIS)

Chung, Bub Dong; Jeong, Jae Jun; Lee, Won Jae

1998-01-01

The two independent codes, MARS 1.3 and CONTEMPT4/MOD5/PCCS, have been coupled using the method of dynamic-link-library (DLL) technique. Overall configuration of the code system is designed so that MARS will be a main driver program which use CONTEMPT as associated routines. Using Digital Visual Fortran compiler, DLL was generated from the CONTEMPT source code with the interfacing routine names and arguments. Coupling of MARS with CONTEMPT was realized by calling the DLL routines at the appropriate step in the MARS code. Verification of coupling was carried out for LBLOCA transient of a typical plant design. It was found that the DLL technique is much more convenient than the UNIX process control techniques and effective for Window operating system. Since DLL can be used by more than one application and an application program can use many DLLs simultaneously, this technique would enable the existing codes to use more broadly with linking others

MARS 1.3 system analysis code coupling with CONTEMPT4/MOD5/PCCS containment analysis code using dynamic link library

Energy Technology Data Exchange (ETDEWEB)

Chung, Bub Dong; Jeong, Jae Jun; Lee, Won Jae [KAERI, Taejon (Korea, Republic of)

1998-10-01

The two independent codes, MARS 1.3 and CONTEMPT4/MOD5/PCCS, have been coupled using the method of dynamic-link-library (DLL) technique. Overall configuration of the code system is designed so that MARS will be a main driver program which use CONTEMPT as associated routines. Using Digital Visual Fortran compiler, DLL was generated from the CONTEMPT source code with the interfacing routine names and arguments. Coupling of MARS with CONTEMPT was realized by calling the DLL routines at the appropriate step in the MARS code. Verification of coupling was carried out for LBLOCA transient of a typical plant design. It was found that the DLL technique is much more convenient than the UNIX process control techniques and effective for Window operating system. Since DLL can be used by more than one application and an application program can use many DLLs simultaneously, this technique would enable the existing codes to use more broadly with linking others.

The Use of Coupled Code Technique for Best Estimate Safety Analysis of Nuclear Power Plants

International Nuclear Information System (INIS)

Bousbia Salah, A.; D'Auria, F.

2006-01-01

Issues connected with the thermal-hydraulics and neutronics of nuclear plants still challenge the design, safety and the operation of Light Water nuclear Reactors (LWR). The lack of full understanding of complex mechanisms related to the interaction between these issues imposed the adoption of conservative safety limits. Those safety margins put restrictions on the optimal exploitation of the plants and consequently reduced economic profit of the plant. In the light of the sustained development in computer technology, the possibilities of code capabilities have been enlarged substantially. Consequently, advanced safety evaluations and design optimizations that were not possible few years ago can now be performed. In fact, during the last decades Best Estimate (BE) neutronic and thermal-hydraulic calculations were so far carried out following rather parallel paths with only few interactions between them. Nowadays, it becomes possible to switch to new generation of computational tools, namely, Coupled Code technique. The application of such method is mandatory for the analysis of accident conditions where strong coupling between the core neutronics and the primary circuit thermal-hydraulics, and more especially when asymmetrical processes take place in the core leading to local space-dependent power generation. Through the current study, a demonstration of the maturity level achieved in the calculation of 3-D core performance during complex accident scenarios in NPPs is emphasized. Typical applications are outlined and discussed showing the main features and limitations of this technique. (author)

Improving Student Engagement in a Lower-Division Botany Course

Science.gov (United States)

Goldberg, Nisse A.; Ingram, Kathleen W.

2011-01-01

Active-learning techniques have been advocated as a means to promote student engagement in lower-division biology courses. In this case study, mini-lectures in combination with active-learning activities were evaluated as strategies to promote a culture of learning and participation in a required botany course. These activities were designed to…

The research of atmospheric 2D optical PPM CDMA system with turbo coding

Science.gov (United States)

Zhou, Xiuli; Li, Zaoxia

2007-11-01

The atmospheric two-dimensional optical code-division multiple-access (CDMA) systems using pulse-position modulation (PPM) and Turbo-coded were presented. We analyzed the bit-error rate (BER) of the proposed system using pulse-position modulation (PPM) with considering the effects of the scintillation, avalanche photodiode noise, thermal noise, and multi-user interference. We showed that the atmospheric two dimensional (2D) optical PPM CDMA systems can realize high-speed communications when the logarithm variance of the scintillation is less than 0.1, and the turbo-coded atmospheric optical CDMA system has better bit error rate(BER) performance than the atmospheric optical PPM CDMA systems without turbo-coded. We also showed that the turbo-coded system has better performance than the multi-user detection system.

Coding Military Command as a Promiscuous Practice

DEFF Research Database (Denmark)

Ashcraft, Karen Lee; Muhr, Sara Louise

2018-01-01

by translating the vague promise of queering leadership into a tangible method distinguished by specific habits. The article formulates this analytical practice out of empirical provocations encountered by the authors: namely, a striking mismatch between their experiences in military fields and the dominant......Despite abundant scholarship addressed to gender equity in leadership, much leadership literature remains invested in gender binaries. Metaphors of leadership are especially dependent on gender oppositions, and this article treats the scholarly practice of coding leadership through gendered...... metaphor as a consequential practice of leadership unto itself. Drawing on queer theory, the article develops a mode of analysis, called ‘promiscuous coding’, conducive to disrupting the gender divisions that currently anchor most leadership metaphors. Promiscuous coding can assist leadership scholars...

Multi element synthetic aperture transmission using a frequency division approach

DEFF Research Database (Denmark)

Gran, Fredrik; Jensen, Jørgen Arendt

2003-01-01

transmitted into the tissue is low. This paper describes a novel method in which the available spectrum is divided into 2N overlapping subbands. This will assure a smooth broadband high resolution spectrum when combined. The signals are grouped into two subsets in which all signals are fully orthogonal...... can therefore be used for flow imaging, unlike with Hadamard and Golay coding. The frequency division approach increases the SNR by a factor of N2 compared to conventional pulsed synthetic aperture imaging, provided that N transmission centers are used. Simulations and phantom measurements...

Application of the partitive analytical forecasting (PAF) technique to the United States controlled thermonuclear research effort

International Nuclear Information System (INIS)

Nichols, S.P.

1975-01-01

The Partitive Analytical Forecasting (PAF) technique is applied to the overall long-term program plans for the Division of Controlled Thermonuclear Research (DCTR) of the United States Energy Research and Development Administration (ERDA). As part of the PAF technique, the Graphical Evaluation and Review Technique (GERTS) IIIZ computer code is used to perform simulations on a logic network describing the DCTR long-term program plan. Logic networks describing the tokamak, mirror, and theta-pinch developments are simulated individually and then together to form an overall DCTR program network. The results of the simulation of the overall network using various funding schemes and strategies are presented. An economic sensitivity analysis is provided for the tokamak logic networks. An analysis is also performed of the fusion-fission hybrid concept in the context of the present DCTR goals. The results mentioned above as well as the PAF technique itself are evaluated, and recommendations for further research are discussed

MORSE Monte Carlo code

International Nuclear Information System (INIS)

Cramer, S.N.

1984-01-01

The MORSE code is a large general-use multigroup Monte Carlo code system. Although no claims can be made regarding its superiority in either theoretical details or Monte Carlo techniques, MORSE has been, since its inception at ORNL in the late 1960s, the most widely used Monte Carlo radiation transport code. The principal reason for this popularity is that MORSE is relatively easy to use, independent of any installation or distribution center, and it can be easily customized to fit almost any specific need. Features of the MORSE code are described

Radiochemistry Division biennial progress report: 1995-1996

International Nuclear Information System (INIS)

Tomar, B.S.; Pujari, P.K.; Mathur, J.N.; Mohapatra, P.K.; Murali, M.S.; Natarajan, V.; Jayanthakumar, M.L.

1997-01-01

The research and development activities of Radiochemistry Division during 1995-96 are briefly described under the headings : (1) nuclear chemistry; (2) actinide chemistry; (3) spectroscopy and (4) instrumentation. Nuclear chemistry work deals with the areas of nuclear reactions, nuclear spectroscopy, nuclear probes and radioanalytical techniques. The research programme in actinide chemistry centered on development of novel procedures for the separation of actinides, guest-host chemistry of lanthanides, actinides and fission products and extractants for solvent extraction. Spectroscopy section activities are summarised under (1) basic research in the solid state chemistry; (2) development of analytical spectroscopic methods for the trace metal determination in nuclear materials; (3) chemical quality control of plutonium 239, uranium 233 and thorium based nuclear fuels. Instrumentation group deals mainly with servicing and maintenance of electronic instruments and allied systems. A list of publications, by the scientific staff of the Divisions is also included. (author)

Radiochemistry Division biennial progress report: 1995-1996

Energy Technology Data Exchange (ETDEWEB)

Tomar, B S; Pujari, P K; Mathur, J N; Mohapatra, P K; Murali, M S; Natarajan, V; Jayanthakumar, M L [eds.; Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai (India)

1998-12-31

The research and development activities of Radiochemistry Division during 1995-96 are briefly described under the headings : (1) nuclear chemistry; (2) actinide chemistry; (3) spectroscopy and (4) instrumentation. Nuclear chemistry work deals with the areas of nuclear reactions, nuclear spectroscopy, nuclear probes and radioanalytical techniques. The research programme in actinide chemistry centered on development of novel procedures for the separation of actinides, guest-host chemistry of lanthanides, actinides and fission products and extractants for solvent extraction. Spectroscopy section activities are summarised under (1) basic research in the solid state chemistry; (2) development of analytical spectroscopic methods for the trace metal determination in nuclear materials; (3) chemical quality control of plutonium 239, uranium 233 and thorium based nuclear fuels. Instrumentation group deals mainly with servicing and maintenance of electronic instruments and allied systems. A list of publications, by the scientific staff of the Divisions is also included. (author)

Topology-selective jamming of fully-connected, code-division random-access networks

Science.gov (United States)

Polydoros, Andreas; Cheng, Unjeng

1990-01-01

The purpose is to introduce certain models of topology selective stochastic jamming and examine its impact on a class of fully-connected, spread-spectrum, slotted ALOHA-type random access networks. The theory covers dedicated as well as half-duplex units. The dominant role of the spatial duty factor is established, and connections with the dual concept of time selective jamming are discussed. The optimal choices of coding rate and link access parameters (from the users' side) and the jamming spatial fraction are numerically established for DS and FH spreading.

Report of the Nuclear Physics Division, January 1, 1978 -December 31, 1979

International Nuclear Information System (INIS)

Thaper, C.L.; Ajitanand, N.N.; Kerekatte, S.S.

1980-01-01

The research activities, with an individual summary of each, of the Nuclear Physics Division of the Bhabha Atomic Research Centre, Bombay, during the calendar years 1978 and 1979 are reported. The Division is organised into three sections, namely, the Solid State physics Section, the Fission Physics Section and the Van de Graaff Laboratory. The supporting facilities of the Division include a workshop, and facilities for electronic design and development, neutron radiography and accelerator maintenance. Techniques of neutron scattering, light scattering and Moessbauer spectroscopy are used for studies in solid state physics. Major activities of the Fission Physics Section relate to theoretical studies of the fission process, heavy ion reactions and nuclear level densities. The activities of this Section during the report period deserving a special mention are studies on the mass division in fission based on the nuclear exchange process and deduction of heavy ion fusion cross sections from fission fragment angular distribution. Experimental work for multiparameter studies of the light charged particles emitted in the thermal induced fission of 235 U and for search of superheavy elements by K X-ray technique is continued. Van de Graaff accelerator is used to study nuclear reactions, nuclear structure and cross sections. Ion beam techniques including ion implantation are used for blistering studies. During the period of the report, 2 MW tandem accelerator was commissioned and DUMAS heavy duty mass separator was tested for performance. A linear, position sensitive X-ray detector has been developed. The report also includes lists of staff members, articles published in journals, papers presented at conferences, symposia etc., reports issued, theses presented, seminars, workshops etc., lecturers delivered by the staff members at other institutions and training courses. (M.G.B.)

Annotated Bibliography of the Advanced Systems Division Reports (1950-1972).

Science.gov (United States)

Valverde, Horace H.; And Others

The Advanced Systems Division of the Air Force Human Resources Laboratory, Air Force Systems Command conducts research and development in the areas of training techniques, psychological and engineering aspects of training equipment, and personnel and training factors in the design of new systems and equipment. This unclassified, unlimited…

Light-water reactor safety analysis codes

International Nuclear Information System (INIS)

Jackson, J.F.; Ransom, V.H.; Ybarrondo, L.J.; Liles, D.R.

1980-01-01

A brief review of the evolution of light-water reactor safety analysis codes is presented. Included is a summary comparison of the technical capabilities of major system codes. Three recent codes are described in more detail to serve as examples of currently used techniques. Example comparisons between calculated results using these codes and experimental data are given. Finally, a brief evaluation of current code capability and future development trends is presented

Random linear codes in steganography

Directory of Open Access Journals (Sweden)

Kamil Kaczyński

2016-12-01

Full Text Available Syndrome coding using linear codes is a technique that allows improvement in the steganographic algorithms parameters. The use of random linear codes gives a great flexibility in choosing the parameters of the linear code. In parallel, it offers easy generation of parity check matrix. In this paper, the modification of LSB algorithm is presented. A random linear code [8, 2] was used as a base for algorithm modification. The implementation of the proposed algorithm, along with practical evaluation of algorithms’ parameters based on the test images was made.[b]Keywords:[/b] steganography, random linear codes, RLC, LSB

Nupack, the new ASME code for radioactive material transportation packaging containments

International Nuclear Information System (INIS)

Turula, P.

1998-01-01

The American Society of Mechanical Engineers (ASME) has added a new division to the nuclear construction section of its Boiler and Pressure Vessel Code (B and PVC). This Division, commonly referred to as Nupack, has been written to provide a consistent set of technical requirements for containment vessels of transportation packagings for high-level radioactive materials. This paper provides an introduction to Nupack, discusses some of its technical provisions, and describes how it can be used for the design and construction of packaging components. Nupack's general provisions and design requirements are emphasized, while treatment of materials, fabrication and inspection is left for another paper

Performance Analysis of a New Coded TH-CDMA Scheme in Dispersive Infrared Channel with Additive Gaussian Noise

Science.gov (United States)

Hamdi, Mazda; Kenari, Masoumeh Nasiri

2013-06-01

We consider a time-hopping based multiple access scheme introduced in [1] for communication over dispersive infrared links, and evaluate its performance for correlator and matched filter receivers. In the investigated time-hopping code division multiple access (TH-CDMA) method, the transmitter benefits a low rate convolutional encoder. In this method, the bit interval is divided into Nc chips and the output of the encoder along with a PN sequence assigned to the user determines the position of the chip in which the optical pulse is transmitted. We evaluate the multiple access performance of the system for correlation receiver considering background noise which is modeled as White Gaussian noise due to its large intensity. For the correlation receiver, the results show that for a fixed processing gain, at high transmit power, where the multiple access interference has the dominant effect, the performance improves by the coding gain. But at low transmit power, in which the increase of coding gain leads to the decrease of the chip time, and consequently, to more corruption due to the channel dispersion, there exists an optimum value for the coding gain. However, for the matched filter, the performance always improves by the coding gain. The results show that the matched filter receiver outperforms the correlation receiver in the considered cases. Our results show that, for the same bandwidth and bit rate, the proposed system excels other multiple access techniques, like conventional CDMA and time hopping scheme.

Lipid Cell Biology: A Focus on Lipids in Cell Division.

Science.gov (United States)

Storck, Elisabeth M; Özbalci, Cagakan; Eggert, Ulrike S

2018-06-20

Cells depend on hugely diverse lipidomes for many functions. The actions and structural integrity of the plasma membrane and most organelles also critically depend on membranes and their lipid components. Despite the biological importance of lipids, our understanding of lipid engagement, especially the roles of lipid hydrophobic alkyl side chains, in key cellular processes is still developing. Emerging research has begun to dissect the importance of lipids in intricate events such as cell division. This review discusses how these structurally diverse biomolecules are spatially and temporally regulated during cell division, with a focus on cytokinesis. We analyze how lipids facilitate changes in cellular morphology during division and how they participate in key signaling events. We identify which cytokinesis proteins are associated with membranes, suggesting lipid interactions. More broadly, we highlight key unaddressed questions in lipid cell biology and techniques, including mass spectrometry, advanced imaging, and chemical biology, which will help us gain insights into the functional roles of lipids.

QR code optical encryption using spatially incoherent illumination

Science.gov (United States)

Cheremkhin, P. A.; Krasnov, V. V.; Rodin, V. G.; Starikov, R. S.

2017-02-01

Optical encryption is an actively developing field of science. The majority of encryption techniques use coherent illumination and suffer from speckle noise, which severely limits their applicability. The spatially incoherent encryption technique does not have this drawback, but its effectiveness is dependent on the Fourier spectrum properties of the image to be encrypted. The application of a quick response (QR) code in the capacity of a data container solves this problem, and the embedded error correction code also enables errorless decryption. The optical encryption of digital information in the form of QR codes using spatially incoherent illumination was implemented experimentally. The encryption is based on the optical convolution of the image to be encrypted with the kinoform point spread function, which serves as an encryption key. Two liquid crystal spatial light modulators were used in the experimental setup for the QR code and the kinoform imaging, respectively. The quality of the encryption and decryption was analyzed in relation to the QR code size. Decryption was conducted digitally. The successful decryption of encrypted QR codes of up to 129  ×  129 pixels was demonstrated. A comparison with the coherent QR code encryption technique showed that the proposed technique has a signal-to-noise ratio that is at least two times higher.

Division par sexe, hiérarchisation des statuts et socialisation corporelle dans les clubs sportifs de judo : vers une neutralisation situationnelle

OpenAIRE

Klein , Emmanuelle

2013-01-01

The framework for the practise of judo is a particular one; it stages elements that make the study of gender division in judo sport clubs particularly interesting. Indeed, the socialisation of the body and the integration of non-official codes of the sport aim at de-Gendering the bodies and the judokas, thus promoting the emergence of neutralized gender relations between judokas. From a situational analysis of the gender division, it was then possible to highlight the fact that gendered statu...

Adaptive RAC codes employing statistical channel evaluation ...

African Journals Online (AJOL)

An adaptive encoding technique using row and column array (RAC) codes employing a different number of parity columns that depends on the channel state is proposed in this paper. The trellises of the proposed adaptive codes and a statistical channel evaluation technique employing these trellises are designed and ...

Division of atomic physics

International Nuclear Information System (INIS)

Kroell, S.

1994-01-01

The Division of Atomic Physics, Lund Institute of Technology (LTH), is responsible for the basic physics teaching in all subjects at LTH and for specialized teaching in Optics, Atomic Physics, Atomic and Molecular Spectroscopy and Laser Physics. The Division has research activities in basic and applied optical spectroscopy, to a large extent based on lasers. It is also part of the Physics Department, Lund University, where it forms one of eight divisions. Since the beginning of 1980 the research activities of our division have been centred around the use of lasers. The activities during the period 1991-1992 is described in this progress reports

Ethical Use of Gestalt Techniques.

Science.gov (United States)

Given, Jane A.

The purpose of this paper is to engender a healthy respect for Gestalt theory and techniques and the use of the techniques in the client's best interest and in the interest of positive professional and self-development in the practitioner. An overview of Gestalt techniques is provided, concentrating on the two category divisions of experiments and…

Computer code ANISN multiplying media and shielding calculation II. Code description (input/output)

International Nuclear Information System (INIS)

Maiorino, J.R.

1990-01-01

The user manual of the ANISN computer code describing input and output subroutines is presented. ANISN code was developed to solve one-dimensional transport equation for neutron or gamma rays in slab, sphere or cylinder geometry with general anisotropic scattering. The solution technique is the discrete ordinate method. (M.C.K.)

Annual report of the Nuclear Physics Division [for] the period ending December 1975

International Nuclear Information System (INIS)

Jain, B.K.; Nadkarni, D.M.; Rao, K.R.P.M.

1976-01-01

The R and D activities of the Nuclear Physics Division of the Bhabha Atomic Research Centre, Bombay, during 1975, are described. The following are the significant areas of research activities of the Division : resonance reactions, nuclear spectra, fast fission, ternary and quaternary fission, neutron diffraction studies of magnetic materials, neutron inelastic scattering and dynamics of condensed media. The progress of development work on various experimental techniques and facilities including ion implantation facility and terminal tandem accelerator has been reported. (M.G.B.)

Development of OCDMA system based on Flexible Cross Correlation (FCC) code with OFDM modulation

Science.gov (United States)

Aldhaibani, A. O.; Aljunid, S. A.; Anuar, M. S.; Arief, A. R.; Rashidi, C. B. M.

2015-03-01

The performance of the OCDMA systems is governed by numerous quantitative parameters such as the data rate, simultaneous number of users, the powers of transmitter and receiver, and the type of codes. This paper analyzes the performance of the OCDMA system using OFDM technique to enhance the channel data rate, to save power and increase the number of user of OSCDMA systems compared with previous hybrid subcarrier multiplexing/optical spectrum code division multiplexing (SCM/OSCDM) system. The average received signal to noise ratio (SNR) with the nonlinearity of subcarriers is derived. The theoretical results have been evaluated based on BER and number of users as well as amount of power saved. The proposed system gave better performance and save around -6 dBm of the power as well as increase the number of users twice compare to SCM/OCDMA system. In addition it is robust against interference and much more spectrally efficient than SCM/OCDMA system. The system was designed based on Flexible Cross Correlation (FCC) code which is easier construction, less complexity of encoder/decoder design and flexible in-phase cross-correlation for uncomplicated to implement using Fiber Bragg Gratings (FBGs) for the OCDMA systems for any number of users and weights. The OCDMA-FCC_OFDM improves the number of users (cardinality) 108% compare to SCM/ODCMA-FCC system.

ASME Code requirements for multi-canister overpack design and fabrication

International Nuclear Information System (INIS)

SMITH, K.E.

1998-01-01

The baseline requirements for the design and fabrication of the MCO include the application of the technical requirements of the ASME Code, Section III, Subsection NB for containment and Section III, Subsection NG for criticality control. ASME Code administrative requirements, which have not historically been applied at the Hanford site and which have not been required by the US Nuclear Regulatory Commission (NRC) for licensed spent fuel casks/canisters, were not invoked for the MCO. As a result of recommendations made from an ASME Code consultant in response to DNFSB staff concerns regarding ASME Code application, the SNF Project will be making the following modifications: issue an ASME Code Design Specification and Design Report, certified by a Registered Professional Engineer; Require the MCO fabricator to hold ASME Section III or Section VIII, Division 2 accreditation; and Use ASME Authorized Inspectors for MCO fabrication. Incorporation of these modifications will ensure that the MCO is designed and fabricated in accordance with the ASME Code. Code Stamping has not been a requirement at the Hanford site, nor for NRC licensed spent fuel casks/canisters, but will be considered if determined to be economically justified

Low Computational Complexity Network Coding For Mobile Networks

DEFF Research Database (Denmark)

Heide, Janus

2012-01-01

Network Coding (NC) is a technique that can provide benefits in many types of networks, some examples from wireless networks are: In relay networks, either the physical or the data link layer, to reduce the number of transmissions. In reliable multicast, to reduce the amount of signaling and enable......-flow coding technique. One of the key challenges of this technique is its inherent computational complexity which can lead to high computational load and energy consumption in particular on the mobile platforms that are the target platform in this work. To increase the coding throughput several...

Repetition code of 15 qubits

Science.gov (United States)

Wootton, James R.; Loss, Daniel

2018-05-01

The repetition code is an important primitive for the techniques of quantum error correction. Here we implement repetition codes of at most 15 qubits on the 16 qubit ibmqx3 device. Each experiment is run for a single round of syndrome measurements, achieved using the standard quantum technique of using ancilla qubits and controlled operations. The size of the final syndrome is small enough to allow for lookup table decoding using experimentally obtained data. The results show strong evidence that the logical error rate decays exponentially with code distance, as is expected and required for the development of fault-tolerant quantum computers. The results also give insight into the nature of noise in the device.

Technical activities, 1990: Surface Science Division

International Nuclear Information System (INIS)

Powell, C.J.

1991-05-01

The report summarizes technical activities and accomplishments of the NIST Surface Science Division during Fiscal Year 1990. Overviews are presented of the Division and of its three constituent groups: Surface Dynamical Processes, Thin Films and Interfaces, and Surface Spectroscopies and Standards. These overviews are followed by reports of selected technical accomplishments during the year. A summary is given of Division outputs and interactions that includes lists of publications, talks, committee assignments, seminars (including both Division seminars and Interface Science seminars arranged through the Division), conferences organized, and a standard reference material certified. Finally, lists are given of Division staff and of guest scientists who have worked in the Division during the past year

Protecting safeguards information / Division of technical support

International Nuclear Information System (INIS)

2002-01-01

This DVD contains two films representing the key aspects of the IAEA Department of Safeguards. 'Protecting Safeguards Information' is a narrative/fiction film which presents the Agency's information handling and protection measures. A security representative from a fictional nation receives a briefing on the procedures and methods used by the Department. These techniques will assure member states that the information they provide to the Agency is kept safe and confidential. 'Division of Technical Support' is a non-fiction documentary which presents a detailed look at the technical capabilities and management techniques used by the Agency in nuclear material accountancy. The film covers many aspects of safeguards equipment and techniques including: NDA and DA instruments, seals, surveillance, training, development and maintenance. Taken together, these films provide an introduction and overview to many important aspects of the IAEA Department of Safeguards. (IAEA)

Progress report: 1996 Radiation Safety Systems Division

International Nuclear Information System (INIS)

Bhagwat, A.M.; Sharma, D.N.; Abani, M.C.; Mehta, S.K.

1997-01-01

The activities of Radiation Safety Systems Division include (i) development of specialised monitoring systems and radiation safety information network, (ii) radiation hazards control at the nuclear fuel cycle facilities, the radioisotope programmes at Bhabha Atomic Research Centre (BARC) and for the accelerators programme at BARC and Centre for Advanced Technology (CAT), Indore. The systems on which development and upgradation work was carried out during the year included aerial gamma spectrometer, automated environment monitor using railway network, radioisotope package monitor and air monitors for tritium and alpha active aerosols. Other R and D efforts at the division included assessment of risk for radiation exposures and evaluation of ICRP 60 recommendations in the Indian context, shielding evaluation and dosimetry for the new upcoming accelerator facilities and solid state nuclear track detector techniques for neutron measurements. The expertise of the divisional members was provided for 36 safety committees of BARC and Atomic Energy Regulatory Board (AERB). Twenty three publications were brought out during the year 1996. (author)

Radiochemical procedures and techniques

International Nuclear Information System (INIS)

Flynn, K.

1975-04-01

A summary is presented of the radiochemical procedures and techniques currently in use by the Chemistry Division Nuclear Chemistry Group at Argonne National Laboratory for the analysis of radioactive samples. (U.S.)

Spatially coded backscatter radiography

International Nuclear Information System (INIS)

Thangavelu, S.; Hussein, E.M.A.

2007-01-01

Conventional radiography requires access to two opposite sides of an object, which makes it unsuitable for the inspection of extended and/or thick structures (airframes, bridges, floors etc.). Backscatter imaging can overcome this problem, but the indications obtained are difficult to interpret. This paper applies the coded aperture technique to gamma-ray backscatter-radiography in order to enhance the detectability of flaws. This spatial coding method involves the positioning of a mask with closed and open holes to selectively permit or block the passage of radiation. The obtained coded-aperture indications are then mathematically decoded to detect the presence of anomalies. Indications obtained from Monte Carlo calculations were utilized in this work to simulate radiation scattering measurements. These simulated measurements were used to investigate the applicability of this technique to the detection of flaws by backscatter radiography

An Efficient Code-Timing Estimator for DS-CDMA Systems over Resolvable Multipath Channels

Directory of Open Access Journals (Sweden)

Jian Li

2005-04-01

Full Text Available We consider the problem of training-based code-timing estimation for the asynchronous direct-sequence code-division multiple-access (DS-CDMA system. We propose a modified large-sample maximum-likelihood (MLSML estimator that can be used for the code-timing estimation for the DS-CDMA systems over the resolvable multipath channels in closed form. Simulation results show that MLSML can be used to provide a high correct acquisition probability and a high estimation accuracy. Simulation results also show that MLSML can have very good near-far resistant capability due to employing a data model similar to that for adaptive array processing where strong interferences can be suppressed.

Nuclear Technology Division annual progress report for period ending June 30, 1974

International Nuclear Information System (INIS)

1975-01-01

Abstracts of research projects are presented concerning nuclear properties, general reactor development and support, test reactor operations support, LOFT support, PBF support, FEFPL support, TRSP support, techniques and instrumentation, non-nuclear energy sources, and related activities of division personnel. (U.S.)

Analysis of preservice inspection relief requests and recommendations for ASME code changes

International Nuclear Information System (INIS)

Cook, J.F.

1985-05-01

NRC regulations require that preservice inspection (PSI) of nuclear plants be performed in accordance with referenced editions and addenda of Division 1 rules of Section XI, ''Rules for Inservice Inspection of Nuclear Power Plant Components'', of the ASME Boiler and Pressure Vessel Code (ASME Code). The regulations permit applicants to request and obtain relief from the NRC from specific ASME Code requirements that are determined to be impractical. Applicant requests for relief from preservice inspection (PSI) requirements were compiled and analyzed. From this data, covering a total of 178 relief requests, common problems with examination requirements were identified. Changes to examination requirements to solve selected problems are proposed. By following later ASME Code requirements, 46 out of the 178 relief requests can be eliminated. Implementing proposed Code changes would eliminate another 25 relief requests, leaving 107 relief requests out of the original 178 relief requests covered by this survey

Construction and performance analysis of variable-weight optical orthogonal codes for asynchronous OCDMA systems

Science.gov (United States)

Li, Chuan-qi; Yang, Meng-jie; Zhang, Xiu-rong; Chen, Mei-juan; He, Dong-dong; Fan, Qing-bin

2014-07-01

A construction scheme of variable-weight optical orthogonal codes (VW-OOCs) for asynchronous optical code division multiple access (OCDMA) system is proposed. According to the actual situation, the code family can be obtained by programming in Matlab with the given code weight and corresponding capacity. The formula of bit error rate (BER) is derived by taking account of the effects of shot noise, avalanche photodiode (APD) bulk, thermal noise and surface leakage currents. The OCDMA system with the VW-OOCs is designed and improved. The study shows that the VW-OOCs have excellent performance of BER. Despite of coming from the same code family or not, the codes with larger weight have lower BER compared with the other codes in the same conditions. By taking simulation, the conclusion is consistent with the analysis of BER in theory. And the ideal eye diagrams are obtained by the optical hard limiter.

Attention Filtering in the Design of Electronic Map Displays: A Comparison of Color-Coding, Intensity Coding, and Decluttering Techniques

National Research Council Canada - National Science Library

Yeh, Michelle; Wickens, Christopher D

2000-01-01

In a series of experiments, the use of color-coding, intensity coding, and decluttering were compared order to assess their potential benefits for accessing information from electronic map displays...

Elastic-plastic code in the static regime for two-dimensional structures

International Nuclear Information System (INIS)

Giuliani, S.

1976-07-01

The finite-element computer code STEP-2D, which was conceived as a numerical tool for basic research in fracture mechanics presently under way in the Materials Division of JRC Ispra is described. The code employs 8-node isoparametric elements for calculating elastic-plastic stress and strain distributions in 2-D geometries. The von Mises yield criterion is used. Material strain hardening is described by means of either the isotropic or the so-called 'overlay' model. An incremental solution is employed in the plastic range. The program has been written in Fortran IV and compiled on an IBM 370-165

Spectral-Amplitude-Coded OCDMA Optimized for a Realistic FBG Frequency Response

Science.gov (United States)

Penon, Julien; El-Sahn, Ziad A.; Rusch, Leslie A.; Larochelle, Sophie

2007-05-01

We develop a methodology for numerical optimization of fiber Bragg grating frequency response to maximize the achievable capacity of a spectral-amplitude-coded optical code-division multiple-access (SAC-OCDMA) system. The optimal encoders are realized, and we experimentally demonstrate an incoherent SAC-OCDMA system with seven simultaneous users. We report a bit error rate (BER) of 2.7 x 10-8 at 622 Mb/s for a fully loaded network (seven users) using a 9.6-nm optical band. We achieve error-free transmission (BER < 1 x 10-9) for up to five simultaneous users.

Document image retrieval through word shape coding.

Science.gov (United States)

Lu, Shijian; Li, Linlin; Tan, Chew Lim

2008-11-01

This paper presents a document retrieval technique that is capable of searching document images without OCR (optical character recognition). The proposed technique retrieves document images by a new word shape coding scheme, which captures the document content through annotating each word image by a word shape code. In particular, we annotate word images by using a set of topological shape features including character ascenders/descenders, character holes, and character water reservoirs. With the annotated word shape codes, document images can be retrieved by either query keywords or a query document image. Experimental results show that the proposed document image retrieval technique is fast, efficient, and tolerant to various types of document degradation.

Information preserving coding for multispectral data

Science.gov (United States)

Duan, J. R.; Wintz, P. A.

1973-01-01

A general formulation of the data compression system is presented. A method of instantaneous expansion of quantization levels by reserving two codewords in the codebook to perform a folding over in quantization is implemented for error free coding of data with incomplete knowledge of the probability density function. Results for simple DPCM with folding and an adaptive transform coding technique followed by a DPCM technique are compared using ERTS-1 data.

Ultrafast two-photon absorption optical thresholding of spectrally coded pulses

Science.gov (United States)

Zheng, Z.; Shen, S.; Sardesai, H.; Chang, C.-C.; Marsh, J. H.; Karkhanehchi, M. M.; Weiner, A. M.

1999-08-01

We report studies on two-photon absorption (TPA) GaAs p-i-n waveguide photodetectors as optical thresholders for proposed ultrashort pulse optical code-division multiple-access (CDMA) systems. For either chirped optical pulses or spectrally phase coded pseudonoise bursts, the TPA photocurrent response reveals a strong pulseshape dependence and shows good agreement with theoretical predictions and results from conventional SHG measurements. The performance limits of the TPA optical thresholders set by the encoded bandwidth in the spectral encoding-decoding process are also discussed based on numerical simulations. Our results show the feasibility of applying such devices as nonlinear intensity discriminators in ultrahigh-speed optical network applications.

Real division algebras and other algebras motivated by physics

International Nuclear Information System (INIS)

Benkart, G.; Osborn, J.M.

1981-01-01

In this survey we discuss several general techniques which have been productive in the study of real division algebras, flexible Lie-admissible algebras, and other nonassociative algebras, and we summarize results obtained using these methods. The principal method involved in this work is to view an algebra A as a module for a semisimple Lie algebra of derivations of A and to use representation theory to study products in A. In the case of real division algebras, we also discuss the use of isotopy and the use of a generalized Peirce decomposition. Most of the work summarized here has appeared in more detail in various other papers. The exceptions are results on a class of algebras of dimension 15, motivated by physics, which admit the Lie algebra sl(3) as an algebra of derivations

Physics, Computer Science and Mathematics Division annual report, January 1--December 31, 1976

International Nuclear Information System (INIS)

Lepore, J.V.

1977-01-01

This annual report of the Physics, Computer Science and Mathematics Division describes the scientific research and other work carried out within the Division during the calendar year 1976. The Division is concerned with work in experimental and theoretical physics, with computer science and applied mathematics, and with the operation of a computer center. The major physics research activity is in high-energy physics; a vigorous program is maintained in this pioneering field. The high-energy physics research program in the Division now focuses on experiments with e + e - colliding beams using advanced techniques and developments initiated and perfected at the Laboratory. The Division continues its work in medium energy physics, with experimental work carried out at the Bevatron and at the Los Alamos Pi-Meson Facility. Work in computer science and applied mathematics includes construction of data bases, computer graphics, computational physics and data analysis, mathematical modeling, and mathematical analysis of differential and integral equations resulting from physical problems. The computer center serves the Laboratory by constantly upgrading its facility and by providing day-to-day service. This report is descriptive in nature; references to detailed publications are given

Physics, Computer Science and Mathematics Division annual report, January 1--December 31, 1976

Energy Technology Data Exchange (ETDEWEB)

Lepore, J.V. (ed.)

1977-01-01

This annual report of the Physics, Computer Science and Mathematics Division describes the scientific research and other work carried out within the Division during the calendar year 1976. The Division is concerned with work in experimental and theoretical physics, with computer science and applied mathematics, and with the operation of a computer center. The major physics research activity is in high-energy physics; a vigorous program is maintained in this pioneering field. The high-energy physics research program in the Division now focuses on experiments with e/sup +/e/sup -/ colliding beams using advanced techniques and developments initiated and perfected at the Laboratory. The Division continues its work in medium energy physics, with experimental work carried out at the Bevatron and at the Los Alamos Pi-Meson Facility. Work in computer science and applied mathematics includes construction of data bases, computer graphics, computational physics and data analysis, mathematical modeling, and mathematical analysis of differential and integral equations resulting from physical problems. The computer center serves the Laboratory by constantly upgrading its facility and by providing day-to-day service. This report is descriptive in nature; references to detailed publications are given. (RWR)

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †.

Science.gov (United States)

Murdani, Muhammad Harist; Kwon, Joonho; Choi, Yoon-Ho; Hong, Bonghee

2018-03-24

In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes ( Ad-Hoc ) and neighborhood proximity ( Top-K ). Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.

Efficient Proximity Computation Techniques Using ZIP Code Data for Smart Cities †

Directory of Open Access Journals (Sweden)

Muhammad Harist Murdani

2018-03-01

Full Text Available In this paper, we are interested in computing ZIP code proximity from two perspectives, proximity between two ZIP codes (Ad-Hoc and neighborhood proximity (Top-K. Such a computation can be used for ZIP code-based target marketing as one of the smart city applications. A naïve approach to this computation is the usage of the distance between ZIP codes. We redefine a distance metric combining the centroid distance with the intersecting road network between ZIP codes by using a weighted sum method. Furthermore, we prove that the results of our combined approach conform to the characteristics of distance measurement. We have proposed a general and heuristic approach for computing Ad-Hoc proximity, while for computing Top-K proximity, we have proposed a general approach only. Our experimental results indicate that our approaches are verifiable and effective in reducing the execution time and search space.

FY16 ASME High Temperature Code Activities

Energy Technology Data Exchange (ETDEWEB)

Swindeman, M. J. [Chromtech Inc., Oak Ridge, TN (United States); Jetter, R. I. [R. I Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

2016-09-01

One of the objectives of the ASME high temperature Code activities is to develop and validate both improvements and the basic features of Section III, Division 5, Subsection HB, Subpart B (HBB). The overall scope of this task is to develop a computer program to be used to assess whether or not a specific component under specified loading conditions will satisfy the elevated temperature design requirements for Class A components in Section III, Division 5, Subsection HB, Subpart B (HBB). There are many features and alternative paths of varying complexity in HBB. The initial focus of this task is a basic path through the various options for a single reference material, 316H stainless steel. However, the program will be structured for eventual incorporation all the features and permitted materials of HBB. Since this task has recently been initiated, this report focuses on the description of the initial path forward and an overall description of the approach to computer program development.

Computed Radiography: An Innovative Inspection Technique

International Nuclear Information System (INIS)

Klein, William A.; Councill, Donald L.

2002-01-01

Florida Power and Light Company's (FPL) Nuclear Division combined two diverse technologies to create an innovative inspection technique, Computed Radiography, that improves personnel safety and unit reliability while reducing inspection costs. This technique was pioneered in the medical field and applied in the Nuclear Division initially to detect piping degradation due to flow-accelerated corrosion. Component degradation can be detected by this additional technique. This approach permits FPL to reduce inspection costs, perform on line examinations (no generation curtailment), and to maintain or improve both personnel safety and unit reliability. Computed Radiography is a very versatile tool capable of other uses: - improving the external corrosion program by permitting inspections underneath insulation, and - diagnosing system and component problems such as valve positions, without the need to shutdown or disassemble the component. (authors)

E-Division activities report

International Nuclear Information System (INIS)

Barschall, H.H.

1984-07-01

E (Experimental Physics) Division carries out basic and applied research in atomic and nuclear physics, in materials science, and in other areas related to the missions of the Laboratory. Some of the activities are cooperative efforts with other divisions of the Laboratory, and, in a few cases, with other laboratories. Many of the experiments are directly applicable to problems in weapons and energy, some have only potential applied uses, and others are in pure physics. This report presents abstracts of papers published by E (Experimental Physics) Division staff members between July 1983 and June 1984. In addition, it lists the members of the scientific staff of the division, including visitors and students, and some of the assignments of staff members on scientific committees. A brief summary of the budget is included

Bit-wise arithmetic coding for data compression

Science.gov (United States)

Kiely, A. B.

1994-01-01

This article examines the problem of compressing a uniformly quantized independent and identically distributed (IID) source. We present a new compression technique, bit-wise arithmetic coding, that assigns fixed-length codewords to the quantizer output and uses arithmetic coding to compress the codewords, treating the codeword bits as independent. We examine the performance of this method and evaluate the overhead required when used block-adaptively. Simulation results are presented for Gaussian and Laplacian sources. This new technique could be used as the entropy coder in a transform or subband coding system.

Division Quilts: A Measurement Model

Science.gov (United States)

Pratt, Sarah S.; Lupton, Tina M.; Richardson, Kerri

2015-01-01

As teachers seek activities to assist students in understanding division as more than just the algorithm, they find many examples of division as fair sharing. However, teachers have few activities to engage students in a quotative (measurement) model of division. Efraim Fischbein and his colleagues (1985) defined two types of whole-number…

American Chemical Society. Division of Nuclear Chemistry and Technology

International Nuclear Information System (INIS)

Anon.

1991-01-01

The meeting of the 201st American Chemical Society Division of Nuclear Chemistry and Technology was comprised from a variety of topics in this field including: nuclear chemistry, nuclear physics, and nuclear techniques for environmental studies. Particular emphasis was given to fundamental research concerning nuclear structure (seven of the nineteen symposia) and studies of airborne particle monitoring and transport (five symposia). 105 papers were presented

KENO-V code

International Nuclear Information System (INIS)

Cramer, S.N.

1984-01-01

The KENO-V code is the current release of the Oak Ridge multigroup Monte Carlo criticality code development. The original KENO, with 16 group Hansen-Roach cross sections and P 1 scattering, was one ot the first multigroup Monte Carlo codes and it and its successors have always been a much-used research tool for criticality studies. KENO-V is able to accept large neutron cross section libraries (a 218 group set is distributed with the code) and has a general P/sub N/ scattering capability. A supergroup feature allows execution of large problems on small computers, but at the expense of increased calculation time and system input/output operations. This supergroup feature is activated automatically by the code in a manner which utilizes as much computer memory as is available. The primary purpose of KENO-V is to calculate the system k/sub eff/, from small bare critical assemblies to large reflected arrays of differing fissile and moderator elements. In this respect KENO-V neither has nor requires the many options and sophisticated biasing techniques of general Monte Carlo codes

Validation and verification of the ORNL Monte Carlo codes for nuclear safety analysis

International Nuclear Information System (INIS)

Emmett, M.B.

1993-01-01

The process of ensuring the quality of computer codes can be very time consuming and expensive. The Oak Ridge National Laboratory (ORNL) Monte Carlo codes all predate the existence of quality assurance (QA) standards and configuration control. The number of person-years and the amount of money spent on code development make it impossible to adhere strictly to all the current requirements. At ORNL, the Nuclear Engineering Applications Section of the Computing Applications Division is responsible for the development, maintenance, and application of the Monte Carlo codes MORSE and KENO. The KENO code is used for doing criticality analyses; the MORSE code, which has two official versions, CGA and SGC, is used for radiation transport analyses. Because KENO and MORSE were very thoroughly checked out over the many years of extensive use both in the United States and in the international community, the existing codes were open-quotes baselined.close quotes This means that the versions existing at the time the original configuration plan is written are considered to be validated and verified code systems based on the established experience with them

Penile suspensory ligament division for penile augmentation: indications and results.

Science.gov (United States)

Li, Chi-Ying; Kayes, Oliver; Kell, Phillip D; Christopher, Nim; Minhas, Suks; Ralph, David J

2006-04-01

This study assessed the management of patients requesting penile length enhancement by division of the penile suspensory ligament. From September 1998 to January 2005, 42 patients with a variety of etiologies were included; all underwent division of the penile suspensory ligament. The outcome was assessed objectively based on increase in flaccid stretched penile length (SPL) and subjectively using the rates of patient satisfaction. The mean increase in SPL was 1.3+/-0.9 cm (range, -1 to +3 cm), with the addition of a silicone spacer placed between the pubis and penis giving a better outcome (p<0.05). The overall patient satisfaction rate was 35% but lower in the group with penile dysmorphic disorder at 27%. Division of the penile suspensory ligament or other augmentation techniques may increase penile length but usually not to a degree that satisfies the patient. Men with penile dysmorphic disorder often have unrealistic expectations regarding the outcome of surgical intervention and should be encouraged to seek psychological help primarily, with surgery reserved as the last resort.

Iterative channel decoding of FEC-based multiple-description codes.

Science.gov (United States)

Chang, Seok-Ho; Cosman, Pamela C; Milstein, Laurence B

2012-03-01

Multiple description coding has been receiving attention as a robust transmission framework for multimedia services. This paper studies the iterative decoding of FEC-based multiple description codes. The proposed decoding algorithms take advantage of the error detection capability of Reed-Solomon (RS) erasure codes. The information of correctly decoded RS codewords is exploited to enhance the error correction capability of the Viterbi algorithm at the next iteration of decoding. In the proposed algorithm, an intradescription interleaver is synergistically combined with the iterative decoder. The interleaver does not affect the performance of noniterative decoding but greatly enhances the performance when the system is iteratively decoded. We also address the optimal allocation of RS parity symbols for unequal error protection. For the optimal allocation in iterative decoding, we derive mathematical equations from which the probability distributions of description erasures can be generated in a simple way. The performance of the algorithm is evaluated over an orthogonal frequency-division multiplexing system. The results show that the performance of the multiple description codes is significantly enhanced.

The Art of Readable Code

CERN Document Server

Boswell, Dustin

2011-01-01

As programmers, we've all seen source code that's so ugly and buggy it makes our brain ache. Over the past five years, authors Dustin Boswell and Trevor Foucher have analyzed hundreds of examples of "bad code" (much of it their own) to determine why they're bad and how they could be improved. Their conclusion? You need to write code that minimizes the time it would take someone else to understand it-even if that someone else is you. This book focuses on basic principles and practical techniques you can apply every time you write code. Using easy-to-digest code examples from different languag

[The Ethics and Deontology division of the French National Council of Medical Doctors, eight years of activity, 1993-2001].

Science.gov (United States)

Hoerni, Bernard

2011-01-01

The activity of the division of Ethics and deontology of the French National council of medical doctors is analysed by its former president (1993-2001). Among a lot of topics, a new version of the professionnal Code of deontology and patients' information were the main subjects of reflection and action.

H-division quarterly report, October--December 1977

International Nuclear Information System (INIS)

1978-01-01

The Theoretical EOS Group develops theoretical techniques for describing material properties under extreme conditions and constructs equation-of-state (EOS) tables for specific applications. Work this quarter concentrated on a Li equation of state, equation of state for equilibrium plasma, improved ion corrections to the Thomas--Fermi--Kirzhnitz theory, and theoretical estimates of high-pressure melting in metals. The Experimental Physics Group investigates properties of materials at extreme conditions of pressure and temperature, and develops new experimental techniques. Effort this quarter concerned the following: parabolic projectile distortion in the two-state light-gas gun, construction of a ballistic range for long-rod penetrators, thermodynamics and sound velocities in liquid metals, isobaric expansion measurements in Pt, and calculation of the velocity--mass profile of a jet produced by a shaped charge. Code development was concentrated on the PELE code, a multimaterial, multiphase, explicit finite-difference Eulerian code for pool suppression dynamics of a hypothetical loss-of-coolant accident in a nuclear reactor. Activities of the Fluid Dynamics Group were directed toward development of a code to compute the equations of state and transport properties of liquid metals (e.g. Li) and partially ionized dense plasmas, jet stability in the Li reactor system, and the study and problem application of fluid dynamic turbulence theory. 19 figures, 5 tables

Analysis of Non-binary Hybrid LDPC Codes

OpenAIRE

Sassatelli, Lucile; Declercq, David

2008-01-01

In this paper, we analyse asymptotically a new class of LDPC codes called Non-binary Hybrid LDPC codes, which has been recently introduced. We use density evolution techniques to derive a stability condition for hybrid LDPC codes, and prove their threshold behavior. We study this stability condition to conclude on asymptotic advantages of hybrid LDPC codes compared to their non-hybrid counterparts.

Comparison of Concussion Rates Between NCAA Division I and Division III Men's and Women's Ice Hockey Players.

Science.gov (United States)

Rosene, John M; Raksnis, Bryan; Silva, Brie; Woefel, Tyler; Visich, Paul S; Dompier, Thomas P; Kerr, Zachary Y

2017-09-01

Examinations related to divisional differences in the incidence of sports-related concussions (SRC) in collegiate ice hockey are limited. To compare the epidemiologic patterns of concussion in National Collegiate Athletic Association (NCAA) ice hockey by sex and division. Descriptive epidemiology study. A convenience sample of men's and women's ice hockey teams in Divisions I and III provided SRC data via the NCAA Injury Surveillance Program during the 2009-2010 to 2014-2015 academic years. Concussion counts, rates, and distributions were examined by factors including injury activity and position. Injury rate ratios (IRRs) and injury proportion ratios (IPRs) with 95% confidence intervals (CIs) were used to compare concussion rates and distributions, respectively. Overall, 415 concussions were reported for men's and women's ice hockey combined. The highest concussion rate was found in Division I men (0.83 per 1000 athlete-exposures [AEs]), followed by Division III women (0.78/1000 AEs), Division I women (0.65/1000 AEs), and Division III men (0.64/1000 AEs). However, the only significant IRR was that the concussion rate was higher in Division I men than Division III men (IRR = 1.29; 95% CI, 1.02-1.65). The proportion of concussions from checking was higher in men than women (28.5% vs 9.4%; IPR = 3.02; 95% CI, 1.63-5.59); however, this proportion was higher in Division I women than Division III women (18.4% vs 1.8%; IPR = 10.47; 95% CI, 1.37-79.75). The proportion of concussions sustained by goalkeepers was higher in women than men (14.2% vs 2.9%; IPR = 4.86; 95% CI, 2.19-10.77), with findings consistent within each division. Concussion rates did not vary by sex but differed by division among men. Checking-related concussions were less common in women than men overall but more common in Division I women than Division III women. Findings highlight the need to better understand the reasons underlying divisional differences within men's and women's ice hockey and the

Nuclear Physics Divisions progress report for the period 1st January to 31st December 1979

International Nuclear Information System (INIS)

Sofield, C.J.; Lees, E.W.; Longworth, G.

1980-04-01

The annual progress report of the Nuclear Physics Division of the Atomic Energy Research Division of the Atomic Energy Research Establishment, Harwell for 1979, is presented under the headings; nuclear data and technology for nuclear power, nuclear studies, applications of nuclear and associated techniques, and accelerator operation, maintenance and development. Lists of reports, publications and conference papers and also of divisional, attached and research student staff are appended. (U.K.)

Lightening protection, techniques, applied codes and standards. Vol. 4

International Nuclear Information System (INIS)

Mahmoud, M.; Shaaban, H.; Lamey, S.

1996-01-01

Lightening is the only natural disaster that protection against is highly effective. Therefore for the safety of critical installations specifically nuclear, an effective lightening protection system (LPS) is required. The design and installation of LPS's have been addressed by many international codes and standards. In this paper, the various LPS's are discussed and compared, including radioactive air terminals, ionizing air terminals, and terminals equipped with electrical trigging devices. Also, the so-called dissipation array systems are discussed and compared to other systems technically and economically. Moreover, the available international codes and standards related to the lightening protection are discussed. such standards include those published by the national fire protection association (NFPA), lightening protection institute (LPI), underwriters laboratories (UL), and british standards Finally, the possibility of developing an egyptian national standards is discussed

Permanent phonetic identification code for radiation workers

International Nuclear Information System (INIS)

Khatua, R.; Somasundaram, S.; Srivastava, D.N.

1987-01-01

This report describes a system of self-checking short and easily memorisable 4-digit 'Permanent Phonetic Radiation Code' (PPRC) using radix 128 for Indians occupationally exposed to radiation, to facilitate entry of all radiation dose data pertaining to an individual in a single record of a file. The logic of PPRC is computer compatible. The necessary computer program has been developed in Health Physics Division for printing the PPRCs in Devanagari script through dot-matrix printers for making it understandable to the majority of the persons concerned. (author)

Monomial codes seen as invariant subspaces

Directory of Open Access Journals (Sweden)

García-Planas María Isabel

2017-08-01

Full Text Available It is well known that cyclic codes are very useful because of their applications, since they are not computationally expensive and encoding can be easily implemented. The relationship between cyclic codes and invariant subspaces is also well known. In this paper a generalization of this relationship is presented between monomial codes over a finite field and hyperinvariant subspaces of n under an appropriate linear transformation. Using techniques of Linear Algebra it is possible to deduce certain properties for this particular type of codes, generalizing known results on cyclic codes.

Overview of hypersonic CFD code calibration studies

Science.gov (United States)

Miller, Charles G.

1987-01-01

The topics are presented in viewgraph form and include the following: definitions of computational fluid dynamics (CFD) code validation; climate in hypersonics and LaRC when first 'designed' CFD code calibration studied was initiated; methodology from the experimentalist's perspective; hypersonic facilities; measurement techniques; and CFD code calibration studies.

Progress report of Physics Division. 1 October 1979 - 30 September 1980. Acting Division Chief - Dr. J. Parry

International Nuclear Information System (INIS)

2004-01-01

The work of the Division concentrated on topics reported in the previous Progress Report with one additional project, namely, the application of ion beam techniques and laser annealing to the production of photovoltaic devices. The MOATA reactor and 3 MeV accelerator operated for Divisional projects and for other work, including collaborative projects supported by the Australian Institute of Nuclear Science and Engineering. Staff were seconded to the Reactors Department (New Reactor Study) and to universities (plasma physics and fusion program). Results obtained on four main themes (reactor calculations, neutron physics, nuclear applications and plasma physics) are reported in the following sections (author)

Chemical Technology Division annual technical report 1989

International Nuclear Information System (INIS)

1990-03-01

Highlights of the Chemical Technology (CMT) Division's activities during 1989 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including high-performance batteries (mainly lithium/iron sulfide and sodium/metal chloride), aqueous batteries (lead-acid and nickel/iron), and advanced fuel cells with molten carbonate and solid oxide electrolytes: (2) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants and the technology for fluidized-bed combustion; (3) methods for recovery of energy from municipal waste and techniques for treatment of hazardous organic waste; (4) nuclear technology related to a process for separating and recovering transuranic elements from nuclear waste and for producing 99 Mo from low-enriched uranium targets, the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor (the Integral Fast Reactor), and waste management; and (5) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for superconducting oxides and associated and ordered solutions at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be administratively responsible for and the major user of the Analytical Chemistry Laboratory at Argonne National Laboratory (ANL)

Chemical Technology Division annual technical report, 1988

International Nuclear Information System (INIS)

1989-05-01

Highlights of the Chemical Technology (CMT) Divisions's activities during 1988 are presented. In this period, CMT conducted research and development in the following areas: (1) high-performance batteries (mainly lithium-alloy/metal sulfide, sodium/metal chloride, and sodium/sulfur); (2) aqueous batteries (lead-acid, nickel/iron, etc.); (3) advanced fuel cells with molten carbonate or solid oxide electrolytes; (4) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants and the technology for fluidized-bed combustion; (5) methods for recovery of energy from municipal waste and techniques for treatment of hazardous chemical water; (6) nuclear technology related to a process for separating and recovering transuranic elements from nuclear waste and for producing /sup 99/Mo from low-enriched uranium targets, the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor, and waste management; and (7) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for superconducting oxides and associated and ordered solutions at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be the major user of the technical support provided by the Analytical Chemistry Laboratory at ANL. 53 figs., 16 tabs

Simulation realization of 2-D wavelength/time system utilizing MDW code for OCDMA system

Science.gov (United States)

Azura, M. S. A.; Rashidi, C. B. M.; Aljunid, S. A.; Endut, R.; Ali, N.

2017-11-01

This paper presents a realization of Wavelength/Time (W/T) Two-Dimensional Modified Double Weight (2-D MDW) code for Optical Code Division Multiple Access (OCDMA) system based on Spectral Amplitude Coding (SAC) approach. The MDW code has the capability to suppress Phase-Induce Intensity Noise (PIIN) and minimizing the Multiple Access Interference (MAI) noises. At the permissible BER 10-9, the 2-D MDW (APD) had shown minimum effective received power (Psr) = -71 dBm that can be obtained at the receiver side as compared to 2-D MDW (PIN) only received -61 dBm. The results show that 2-D MDW (APD) has better performance in achieving same BER with longer optical fiber length and with less received power (Psr). Also, the BER from the result shows that MDW code has the capability to suppress PIIN ad MAI.

Simulation realization of 2-D wavelength/time system utilizing MDW code for OCDMA system

Directory of Open Access Journals (Sweden)

Azura M. S. A.

2017-01-01

Full Text Available This paper presents a realization of Wavelength/Time (W/T Two-Dimensional Modified Double Weight (2-D MDW code for Optical Code Division Multiple Access (OCDMA system based on Spectral Amplitude Coding (SAC approach. The MDW code has the capability to suppress Phase-Induce Intensity Noise (PIIN and minimizing the Multiple Access Interference (MAI noises. At the permissible BER 10-9, the 2-D MDW (APD had shown minimum effective received power (Psr = -71 dBm that can be obtained at the receiver side as compared to 2-D MDW (PIN only received -61 dBm. The results show that 2-D MDW (APD has better performance in achieving same BER with longer optical fiber length and with less received power (Psr. Also, the BER from the result shows that MDW code has the capability to suppress PIIN ad MAI.

Fast decoder for local quantum codes using Groebner basis

Science.gov (United States)

Haah, Jeongwan

2013-03-01

Based on arXiv:1204.1063. A local translation-invariant quantum code has a description in terms of Laurent polynomials. As an application of this observation, we present a fast decoding algorithm for translation-invariant local quantum codes in any spatial dimensions using the straightforward division algorithm for multivariate polynomials. The running time is O (n log n) on average, or O (n2 log n) on worst cases, where n is the number of physical qubits. The algorithm improves a subroutine of the renormalization-group decoder by Bravyi and Haah (arXiv:1112.3252) in the translation-invariant case. This work is supported in part by the Insitute for Quantum Information and Matter, an NSF Physics Frontier Center, and the Korea Foundation for Advanced Studies.

Goddard's Astrophysics Science Division Annual Report 2013

Science.gov (United States)

Weaver, Kimberly A. (Editor); Reddy, Francis J. (Editor); Tyler, Patricia A. (Editor)

2014-01-01

The Astrophysics Science Division (ASD) at Goddard Space Flight Center (GSFC) is one of the largest and most diverse astrophysical organizations in the world, with activities spanning a broad range of topics in theory, observation, and mission and technology development. Scientific research is carried out over the entire electromagnetic spectrum from gamma rays to radio wavelengths as well as particle physics and gravitational radiation. Members of ASD also provide the scientific operations for two orbiting astrophysics missions Fermi Gamma-ray Space Telescope and Swift as well as the Science Support Center for Fermi. A number of key technologies for future missions are also under development in the Division, including X-ray mirrors, space-based interferometry, high contrast imaging techniques to search for exoplanets, and new detectors operating at gamma-ray, X-ray, ultraviolet, infrared, and radio wavelengths. The overriding goals of ASD are to carry out cutting-edge scientific research, provide Project Scientist support for spaceflight missions, implement the goals of the NASA Strategic Plan, serve and support the astronomical community, and enable future missions by conceiving new concepts and inventing new technologies.

ETFOD: a point model physics code with arbitrary input

International Nuclear Information System (INIS)

Rothe, K.E.; Attenberger, S.E.

1980-06-01

ETFOD is a zero-dimensional code which solves a set of physics equations by minimization. The technique used is different than normally used, in that the input is arbitrary. The user is supplied with a set of variables from which he specifies which variables are input (unchanging). The remaining variables become the output. Presently the code is being used for ETF reactor design studies. The code was written in a manner to allow easy modificaton of equations, variables, and physics calculations. The solution technique is presented along with hints for using the code

Translational Control of Cell Division by Elongator

Directory of Open Access Journals (Sweden)

Fanelie Bauer

2012-05-01

Full Text Available Elongator is required for the synthesis of the mcm5s2 modification found on tRNAs recognizing AA-ending codons. In order to obtain a global picture of the role of Elongator in translation, we used reverse protein arrays to screen the fission yeast proteome for translation defects. Unexpectedly, this revealed that Elongator inactivation mainly affected three specific functional groups including proteins implicated in cell division. The absence of Elongator results in a delay in mitosis onset and cytokinesis defects. We demonstrate that the kinase Cdr2, which is a central regulator of mitosis and cytokinesis, is under translational control by Elongator due to the Lysine codon usage bias of the cdr2 coding sequence. These findings uncover a mechanism by which the codon usage, coupled to tRNA modifications, fundamentally contributes to gene expression and cellular functions.

Nupack, the new Asme code for radioactive material transportation packaging containments

International Nuclear Information System (INIS)

Turula, P.

1998-01-01

The American Society of Mechanical Engineers (ASME) has added a new division to the nuclear construction section of its Boiler and Pressure Vessel Code (B and PVC). This Division, commonly referred to as 'Nupack', has been written to provide a consistent set of technical requirements for containment vessels of transportation packagings for high-level radioactive materials. This paper provides an introduction to Nupack, discusses some of its technical provisions, and describes how it can be used the design and construction of packaging components. Nupack's general provisions and design requirements are emphasized, while treatment of materials, fabrication and inspection is left for another paper. Participation in the Nupack development work described in this paper was supported by the U.S. Department of Energy. (authors)

Progress report of Physics Division. 1st October 1976 - 30th September 1977. Acting Division Chief - Mr. W. Gemmell

International Nuclear Information System (INIS)

2004-01-01

The maturity of the nuclear industry is exemplified by the increasingly large effort required to improve upon existing levels of knowledge or understanding. Our experiment to provide an accurate measurement of the californium fission neutron spectrum has been delayed by the necessity to investigate the many small correction effects and validate the new features introduced. The same type of painstaking analysis has become necessary in the collaborative studies with Oak Ridge National Laboratory on neutron capture cross sections. Investigation of background, interference and experimental techniques has led to significant revisions of the data and, again, emphasizes the care necessary before such data becomes incorporated into international data collections. A continuing worry in all of this is the adequacy of our major equipment for continuation in these fields. These worries have been lessened by the excitement of some applications ranging from investigations of gas/liquid inclusions in rocks and minerals, to the quite spectacular radiographs of uranium distribution in kidney sections, using solid state track devices. Although our interests lie primarily with an understanding of the polluting processes in uranium mine tailings, it has become obvious that the problem is a general and widespread one. Few physics investigations have been recorded and yet diffusion processes appear to be of prime importance. Most, if not all, the pollution arises from heavy metals other than uranium. interest in reactor safety has moved steadily away from the neutronics to the study of the hydrodynamics of the loss of coolant accident and to an understanding of the convection processes in transient heat transfer. Interesting problems in classical physics have arisen. The main code development interest has been with a new method of numerical iteration which offers prospects for reducing the convergence time of large, three-dimensional codes. Work on interactive computing methods has

Report on R and D activities of Health Physics Division 1994-1995

Energy Technology Data Exchange (ETDEWEB)

Raju, A; Narayanan, K K; Katoch, D S; Sharma, R C [comps.; Health Physics Division, Bhabha Atomic Research Centre, Mumbai (India)

1996-10-01

This report is a compilation of the activities and also of the results of various R and D programmes of the Health Physics Division of Bhabha Atomic Research Centre (BARC) during the period 1994-1995. The topics covered are: environmental studies, radiation dosimetry- internal and external, operational health physics and nuclear safety, instruments and techniques, radiation physics, mathematical modelling and software development, micrometeorology and industrial hygiene. The matter is presented in the form of abstracts with the publication details. Also included are extracts from IAEA research agreements and the summary of theses submitted by the staff members of the Division during the above period.

Report on R and D activities of Health Physics Division 1994-1995

International Nuclear Information System (INIS)

Raju, A.; Narayanan, K.K.; Katoch, D.S.; Sharma, R.C.

1996-10-01

This report is a compilation of the activities and also of the results of various R and D programmes of the Health Physics Division of Bhabha Atomic Research Centre (BARC) during the period 1994-1995. The topics covered are: environmental studies, radiation dosimetry- internal and external, operational health physics and nuclear safety, instruments and techniques, radiation physics, mathematical modelling and software development, micrometeorology and industrial hygiene. The matter is presented in the form of abstracts with the publication details. Also included are extracts from IAEA research agreements and the summary of theses submitted by the staff members of the Division during the above period

Fusion Energy Division progress report, 1 January 1990--31 December 1991

International Nuclear Information System (INIS)

Sheffield, J.; Baker, C.C.; Saltmarsh, M.J.

1994-03-01

The Fusion Program of the Oak Ridge National Laboratory (ORNL), a major part of the national fusion program, encompasses nearly all areas of magnetic fusion research. The program is directed toward the development of fusion as an economical and environmentally attractive energy source for the future. The program involves staff from ORNL, Martin Marietta Energy systems, Inc., private industry, the academic community, and other fusion laboratories, in the US and abroad. Achievements resulting from this collaboration are documented in this report, which is issued as the progress report of the ORNL Fusion Energy Division; it also contains information from components for the Fusion Program that are external to the division (about 15% of the program effort). The areas addressed by the Fusion Program include the following: experimental and theoretical research on magnetic confinement concepts; engineering and physics of existing and planned devices, including remote handling; development and testing of diagnostic tools and techniques in support of experiments; assembly and distribution to the fusion community of databases on atomic physics and radiation effects; development and testing of technologies for heating and fueling fusion plasmas; development and testing of superconducting magnets for containing fusion plasmas; development and testing of materials for fusion devices; and exploration of opportunities to apply the unique skills, technology, and techniques developed in the course of this work to other areas (about 15% of the Division's activities). Highlights from program activities during 1990 and 1991 are presented

Particle tracing code for multispecies gas

International Nuclear Information System (INIS)

Eaton, R.R.; Fox, R.L.; Vandevender, W.H.

1979-06-01

Details are presented for the development of a computer code designed to calculate the flow of a multispecies gas mixture using particle tracing techniques. The current technique eliminates the need for a full simulation by utilizing local time averaged velocity distribution functions to obtain the dynamic properties for probable collision partners. The development of this concept reduces statistical scatter experienced in conventional Monte Carlo simulations. The technique is applicable to flow problems involving gas mixtures with disparate masses and trace constituents in the Knudsen number, Kn, range from 1.0 to less than 0.01. The resulting code has previously been used to analyze several aerodynamic isotope enrichment devices

Hamming Code Based Watermarking Scheme for 3D Model Verification

Directory of Open Access Journals (Sweden)

Jen-Tse Wang

2014-01-01

Full Text Available Due to the explosive growth of the Internet and maturing of 3D hardware techniques, protecting 3D objects becomes a more and more important issue. In this paper, a public hamming code based fragile watermarking technique is proposed for 3D objects verification. An adaptive watermark is generated from each cover model by using the hamming code technique. A simple least significant bit (LSB substitution technique is employed for watermark embedding. In the extraction stage, the hamming code based watermark can be verified by using the hamming code checking without embedding any verification information. Experimental results shows that 100% vertices of the cover model can be watermarked, extracted, and verified. It also shows that the proposed method can improve security and achieve low distortion of stego object.

77 FR 40586 - Coastal Programs Division

Science.gov (United States)

2012-07-10

... DEPARTMENT OF COMMERCE National Oceanic and Atmospheric Administration Coastal Programs Division AGENCY: Coastal Programs Division, Office of Ocean and Coastal Resource Management, National Ocean.... FOR FURTHER INFORMATION CONTACT: Kerry Kehoe, Coastal Programs Division (NORM/3), Office of Ocean and...

The Use of System Codes in Scaling Studies: Relevant Techniques for Qualifying NPP Nodalizations for Particular Scenarios

Directory of Open Access Journals (Sweden)

V. Martinez-Quiroga

2014-01-01

Full Text Available System codes along with necessary nodalizations are valuable tools for thermal hydraulic safety analysis. Qualifying both codes and nodalizations is an essential step prior to their use in any significant study involving code calculations. Since most existing experimental data come from tests performed on the small scale, any qualification process must therefore address scale considerations. This paper describes the methodology developed at the Technical University of Catalonia in order to contribute to the qualification of Nuclear Power Plant nodalizations by means of scale disquisitions. The techniques that are presented include the so-called Kv-scaled calculation approach as well as the use of “hybrid nodalizations” and “scaled-up nodalizations.” These methods have revealed themselves to be very helpful in producing the required qualification and in promoting further improvements in nodalization. The paper explains both the concepts and the general guidelines of the method, while an accompanying paper will complete the presentation of the methodology as well as showing the results of the analysis of scaling discrepancies that appeared during the posttest simulations of PKL-LSTF counterpart tests performed on the PKL-III and ROSA-2 OECD/NEA Projects. Both articles together produce the complete description of the methodology that has been developed in the framework of the use of NPP nodalizations in the support to plant operation and control.

Monte-Carlo method - codes for the study of criticality problems (on IBM 7094); Methode de Monte- Carlo - codes pour l'etude des problemes de criticite (IBM 7094)

Energy Technology Data Exchange (ETDEWEB)

Moreau, J; Rabot, H; Robin, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-07-01

The two codes presented here allow to determine the multiplication constant of media containing fissionable materials under numerous and divided forms; they are based on the Monte-Carlo method. The first code apply to x, y, z, geometries. The volume to be studied ought to be divisible in parallelepipeds, the media within each parallelepiped being limited by non-secant surfaces. The second code is intended for r, 0, z geometries. The results include an analysis of collisions in each medium. Applications and examples with informations on time and accuracy are given. (authors) [French] Les deux codes presentes dans ce rapport permettent la determination des coefficients de multiplication de milieux contenant des matieres fissiles sous des formes tres variees et divisees, ils reposent sur la methode de Monte-Carlo. Le premier code s'applique aux geometries x, y, z, le volume a etudier doit pouvoir etre decompose en parallelepipedes, les milieux a l'interieur de chaque parallelepipede etant limites par des surfaces non secantes. Le deuxieme code s'applique aux geometries r, 0, z. Les resultats comportent une analyse des collisions dans chaque milieu. Des applications et des exemples avec les indications de temps et de precision sont fournis. (auteurs)

Code breaking in the pacific

CERN Document Server

Donovan, Peter

2014-01-01

Covers the historical context and the evolution of the technically complex Allied Signals Intelligence (Sigint) activity against Japan from 1920 to 1945 Describes, explains and analyzes the code breaking techniques developed during the war in the Pacific Exposes the blunders (in code construction and use) made by the Japanese Navy that led to significant US Naval victories

Theoretical Division progress report

International Nuclear Information System (INIS)

Cooper, N.G.

1979-04-01

This report presents highlights of activities in the Theoretical (T) Division from October 1976-January 1979. The report is divided into three parts. Part I presents an overview of the Division: its unique function at the Los Alamos Scientific Laboratory (LASL) and within the scientific community as a whole; the organization of personnel; the main areas of research; and a survey of recent T-Division initiatives. This overview is followed by a survey of the 13 groups within the Division, their main responsibilities, interests, and expertise, consulting activities, and recent scientific accomplisments. The remainder of the report, Parts II and III, is devoted to articles on selected research activities. Recent efforts on topics of immediate interest to energy and weapons programs at LASL and elsewhere are described in Part II, Major National Programs. Separate articles present T-Divison contributions to weapons research, reactor safety and reactor physics research, fusion research, laser isotope separation, and other energy research. Each article is a compilation of independent projects within T Division, all related to but addressing different aspects of the major program. Part III is organized by subject discipline, and describes recent scientific advances of fundamental interest. An introduction, defining the scope and general nature of T-Division efforts within a given discipline, is followed by articles on the research topics selected. The reporting is done by the scientists involved in the research, and an attempt is made to communicate to a general audience. Some data are given incidentally; more technical presentations of the research accomplished may be found among the 47 pages of references. 110 figures, 5 tables

Suture Coding: A Novel Educational Guide for Suture Patterns.

Science.gov (United States)

Gaber, Mohamed; Abdel-Wahed, Ramadan

2015-01-01

This study aims to provide a helpful guide to perform tissue suturing successfully using suture coding-a method for identification of suture patterns and techniques by giving full information about the method of application of each pattern using numbers and symbols. Suture coding helps construct an infrastructure for surgical suture science. It facilitates the easy understanding and learning of suturing techniques and patterns as well as detects the relationship between the different patterns. Guide points are fixed on both edges of the wound to act as a guideline to help practice suture pattern techniques. The arrangement is fixed as 1-3-5-7 and a-c-e-g on one side (whether right or left) and as 2-4-6-8 and b-d-f-h on the other side. Needle placement must start from number 1 or letter "a" and continue to follow the code till the end of the stitching. Some rules are created to be adopted for the application of suture coding. A suture trainer containing guide points that simulate the coding process is used to facilitate the learning of the coding method. (120) Is the code of simple interrupted suture pattern; (ab210) is the code of vertical mattress suture pattern, and (013465)²/3 is the code of Cushing suture pattern. (0A1) Is suggested as a surgical suture language that gives the name and type of the suture pattern used to facilitate its identification. All suture patterns known in the world should start with (0), (A), or (1). There is a relationship between 2 or more surgical patterns according to their codes. It can be concluded that every suture pattern has its own code that helps in the identification of its type, structure, and method of application. Combination between numbers and symbols helps in the understanding of suture techniques easily without complication. There are specific relationships that can be identified between different suture patterns. Coding methods facilitate suture patterns learning process. The use of suture coding can be a good

A computerized energy systems code and information library at Soreq

Energy Technology Data Exchange (ETDEWEB)

Silverman, I; Shapira, M; Caner, D; Sapier, D [Israel Atomic Energy Commission, Yavne (Israel). Soreq Nuclear Research Center

1996-12-01

In the framework of the contractual agreement between the Ministry of Energy and Infrastructure and the Division of Nuclear Engineering of the Israel Atomic Energy Commission, both Soreq-NRC and Ben-Gurion University have agreed to establish, in 1991, a code center. This code center contains a library of computer codes and relevant data, with particular emphasis on nuclear power plant research and development support. The code center maintains existing computer codes and adapts them to the ever changing computing environment, keeps track of new code developments in the field of nuclear engineering, and acquires the most recent revisions of computer codes of interest. An attempt is made to collect relevant codes developed in Israel and to assure that proper documentation and application instructions are available. En addition to computer programs, the code center collects sample problems and international benchmarks to verify the codes and their applications to various areas of interest to nuclear power plant engineering and safety evaluation. Recently, the reactor simulation group at Soreq acquired, using funds provided by the Ministry of Energy and Infrastructure, a PC work station operating under a Linux operating system to give users of the library an easy on-line way to access resources available at the library. These resources include the computer codes and their documentation, reports published by the reactor simulation group, and other information databases available at Soreq. Registered users set a communication line, through a modem, between their computer and the new workstation at Soreq and use it to download codes and/or information or to solve their problems, using codes from the library, on the computer at Soreq (authors).

A computerized energy systems code and information library at Soreq

International Nuclear Information System (INIS)

Silverman, I.; Shapira, M.; Caner, D.; Sapier, D.

1996-01-01

In the framework of the contractual agreement between the Ministry of Energy and Infrastructure and the Division of Nuclear Engineering of the Israel Atomic Energy Commission, both Soreq-NRC and Ben-Gurion University have agreed to establish, in 1991, a code center. This code center contains a library of computer codes and relevant data, with particular emphasis on nuclear power plant research and development support. The code center maintains existing computer codes and adapts them to the ever changing computing environment, keeps track of new code developments in the field of nuclear engineering, and acquires the most recent revisions of computer codes of interest. An attempt is made to collect relevant codes developed in Israel and to assure that proper documentation and application instructions are available. En addition to computer programs, the code center collects sample problems and international benchmarks to verify the codes and their applications to various areas of interest to nuclear power plant engineering and safety evaluation. Recently, the reactor simulation group at Soreq acquired, using funds provided by the Ministry of Energy and Infrastructure, a PC work station operating under a Linux operating system to give users of the library an easy on-line way to access resources available at the library. These resources include the computer codes and their documentation, reports published by the reactor simulation group, and other information databases available at Soreq. Registered users set a communication line, through a modem, between their computer and the new workstation at Soreq and use it to download codes and/or information or to solve their problems, using codes from the library, on the computer at Soreq (authors)

A Novel Real-coded Quantum-inspired Genetic Algorithm and Its Application in Data Reconciliation

Directory of Open Access Journals (Sweden)

Gao Lin

2012-06-01

Full Text Available Traditional quantum-inspired genetic algorithm (QGA has drawbacks such as premature convergence, heavy computational cost, complicated coding and decoding process etc. In this paper, a novel real-coded quantum-inspired genetic algorithm is proposed based on interval division thinking. Detailed comparisons with some similar approaches for some standard benchmark functions test validity of the proposed algorithm. Besides, the proposed algorithm is used in two typical nonlinear data reconciliation problems (distilling process and extraction process and simulation results show its efficiency in nonlinear data reconciliation problems.

Analysis of PPM-CDMA and OPPM-CDMA communication systems with new optical code

Science.gov (United States)

Liu, F.; Ghafouri-Shiraz, H.

2005-11-01

A novel type of optical spreading sequences, named the 'new-Modified Prime Code (nMPC)', is proposed for use in synchronous direct-detection optical code-division multiple-access (CDMA) systems which employ both pulse position modulation (PPM) and overlapping pulse position modulation (OPPM) schemes. The upper bounds on the bit error rate (BER) for nMPC used in PPM-CDMA systems are derived and compared with the respective systems, using a modified prime code (MPC) and a padded modified prime code (PMPC). The nMPC is further applied to the OPPM-CDMA system and the system with a proposed interference cancellation scheme. Our results show that under the same conditions the PPM-CDMA system performances are more improved with the use of nMPC than with the two other traditional codes. Moreover, they show that the system performances are significantly enhanced by the proposed interference reduction methods, if the nMPC is used in the OPPM-CDMA systems.

Prokaryotic cell division: flexible and diverse

NARCIS (Netherlands)

den Blaauwen, T.

2013-01-01

Gram-negative rod-shaped bacteria have different approaches to position the cell division initiating Z-ring at the correct moment in their cell division cycle. The subsequent maturation into a functional division machine occurs in vastly different species in two steps with appreciable time in

Fusion energy division computer systems network

International Nuclear Information System (INIS)

Hammons, C.E.

1980-12-01

The Fusion Energy Division of the Oak Ridge National Laboratory (ORNL) operated by Union Carbide Corporation Nuclear Division (UCC-ND) is primarily involved in the investigation of problems related to the use of controlled thermonuclear fusion as an energy source. The Fusion Energy Division supports investigations of experimental fusion devices and related fusion theory. This memo provides a brief overview of the computing environment in the Fusion Energy Division and the computing support provided to the experimental effort and theory research

Experimental demonstration of polar coded IM/DD optical OFDM for short reach system

Science.gov (United States)

Fang, Jiafei; Xiao, Shilin; Liu, Ling; Bi, Meihua; Zhang, Lu; Zhang, Yunhao; Hu, Weisheng

2017-11-01

In this paper, we propose a novel polar coded intensity modulation direct detection (IM/DD) optical orthogonal frequency division multiplexing (OFDM) system for short reach system. A method of evaluating the channel signal noise ratio (SNR) is proposed for soft-demodulation. The experimental results demonstrate that, compared to the conventional case, ∼9.5 dB net coding gain (NCG) at the bit error rate (BER) of 1E-3 can be achieved after 40-km standard single mode fiber (SSMF) transmission. Based on the experimental result, (512,256) polar code with low complexity and satisfactory BER performance meets the requirement of low latency in short reach system, which is a promising candidate for latency-stringent short reach optical system.

Correction of Residual Ventral Penile Curvature After Division of the Urethral Plate in the First Stage of a 2-Stage Proximal Hypospadias Repair.

Science.gov (United States)

Schlomer, Bruce J

2017-02-01

The first stage of a 2-stage proximal hypospadias repair involves division of the urethral plate and correction of any residual ventral penile curvature (VPC). Options to correct residual VPC include dorsal corporal shortening or ventral corporal lengthening techniques. This review discusses these options and suggests an approach to management. Recent reports of 2-stage proximal hypospadias repairs indicate low rates of recurrent VPC with either dorsal corporal shortening or ventral corporal lengthening. Dorsal corporal shortening with dorsal plication may be preferentially used for mild to moderate residual VPC after division of urethral plate and ventral corporal lengthening reserved for severe residual VPC. Ventral corporal lengthening with grafts has been associated with urethroplasty complications after the second stage hypospadias surgery. Ventral corporal lengthening with relaxing incisions of corpora has been reported, but concerns about adverse effects require longer term studies. Little guidance exists to choose the best technique for VPC correction during first stage hypospadias repair after division of urethral plate. Reported literature suggests good results with dorsal plication techniques and ventral corporal lengthening. A practical approach is to use dorsal plication techniques for mild to moderate residual VPC after division of urethral plate (lengthening for severe residual VPC (>45°).

Position readout by charge division in large two-dimensional detectors

International Nuclear Information System (INIS)

Alberi, J.L.

1976-10-01

The improvement in readout spatial resolution for charge division systems with subdivided readout electrodes has been analyzed. This readout forms the position and sum signals by a linear, unambiguous analogue summation technique. It is shown that the readout resolution is a function of only electrode capacitance and shaping parameters. The line width improves as 1/N/sup 1 / 2 /, where N is the number of electrode subdivisions

Neural Decoder for Topological Codes

Science.gov (United States)

Torlai, Giacomo; Melko, Roger G.

2017-07-01

We present an algorithm for error correction in topological codes that exploits modern machine learning techniques. Our decoder is constructed from a stochastic neural network called a Boltzmann machine, of the type extensively used in deep learning. We provide a general prescription for the training of the network and a decoding strategy that is applicable to a wide variety of stabilizer codes with very little specialization. We demonstrate the neural decoder numerically on the well-known two-dimensional toric code with phase-flip errors.

The Morphosyntactic Structure of the Noun and Verb Phrases in Dholuo/Kiswahili Code Switching

Directory of Open Access Journals (Sweden)

Jael Anyango Ojanga

2015-04-01

Full Text Available Code switching, the use of any two or more languages or dialects interchangeably in a single communication context, is a common linguistic practice owing to the trend of multilingualism in the world today. In many situations of language in contact, constituents of one language can be found within the constituents of another language in a number of linguistic phenomenon namely lexical borrowing, transferring, interference, code switching and diffusion (Annamalai, 1989. Codeswitching is one of the linguistic phenomenon claimed to be the most prevalent and common mode of interaction among multilingual speakers. Brock and Eastman (1971 suggest that topic discussed influences the choice of the language. Nouns and verbs have been found to be the most code switched elements in bilingual exchange. The study took a qualitative approach with the descriptive research design. It was guided by the Matrix Language Frame Model which was formulated by Myers-Scotton in1993. This model expounds on the realization and structure of the major word classes as used in code switching. Data was collected in Nyangeta Zone, Winam Division of Kisumu East District. Winam Division is mostly inhabited by elite Dholuo L1 speakers. A sample of twenty four teachers was purposively selected to provide data needed for the study. Focus group discussion was used to collect a corpus of Dholuo/Kiswahili data which was recorded through audio taping. The recorded data was then analyzed morphosyntactaically using the Matrix Language Frame Model. The data revealed that the noun and verb phrases were realized under three categories: Matrix Language Island constituent (ML Island ML+EL and Embedded Language Island (EL Island. Keywords: Code switching, multilingualism, morphosyntactic

Optimisation des codes LDPC irréguliers et algorithmes de décodage des codes LDPC q-aires

OpenAIRE

Cances , Jean-Pierre

2013-01-01

Cette note technique rappelle les principes d'optimisation pour obtenir les profils de codes LDPC irréguliers performants et rappelle les principes des algorithmes de décodage utilizes pour les codes LDPC q-aires à grande efficacité spectrale.

Engineering Physics Division progress report for period ending November 30, 1978

International Nuclear Information System (INIS)

Maienschein, F.C.

1979-01-01

Research and other activities of the Engineering Physics Division (formerly Neutron Physics Division) of ORNL during the period February 28, 1977 to November 30, 1978, are reported. The format is that of abstracts and summaries of prepared papers. Work is summarized in the following general areas: measurements of neutron cross sections and related quantities; cross-section theory, evaluations, and evaluation techniques; cross-section processing, testing, and sensitivity analyses; integral experiments and their analyses; development of methods for shield and reactor analyses; analyses for specific systems or applications (liquid-metal fast breeder reactor program, gas-cooled reactor program, alternate fuel cycle program, magnetic fusion energy program, high-energy physics program, accelerator breeding studies, miscellaneous studies); and information analysis and distribution. Overviews of each of these areas are included

The COSMOS-S/D assessment code complex for a SLB repository at CRNL

International Nuclear Information System (INIS)

Jarvis, R.G.; Adam, R.Y.; Bretzlaff, C.I.; Laurens, J.M.; Wilkinson, S.R.

1986-12-01

The COSMOS-S/D code complex is being developed by the Waste Management Technology Division at CRNL. It models leaching of radionuclides from containment, their migration through vault materials and the ground, their dispersion in surface waters and the atmosphere, and eventual irradiation of man. It is being used at present for safety assessment of a proposed shallow Land Burial Facility, but is is suitable for a wide range of shallow land burial problems. Some examples of its output are given. The scenarios were chosen to be rather conservative, in order to demonstrate the various sections of the code

Chemical technology division: Annual technical report 1987

International Nuclear Information System (INIS)

1988-05-01

Highlights of the Chemical Technology (CMT) Division's activities during 1987 are presented. In this period, CMT conducted research and development in the following areas: (1) high-performance batteries--mainly lithium-alloy/metal sulfide and sodium/sulfur; (2) aqueous batteries (lead-acid, nickel/iron, etc.); (3) advanced fuel cells with molten carbonate or solid oxide electrolytes; (4) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants and the technology for fluidized-bed combustion; (5) methods for the electromagnetic continuous casting of steel sheet and for the purification of ferrous scrap; (6) methods for recovery of energy from municipal waste and techniques for treatment of hazardous organic waste; (7) nuclear technology related to a process for separating and recovering transuranic elements from nuclear waste, the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor, and waste management; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for liquids and vapors at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; the thermochemistry of various minerals; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be the major user of the technical support provided by the Analytical Chemistry Laboratory at ANL. 54 figs., 9 tabs

Chemical Technology Division annual technical report 1989

Energy Technology Data Exchange (ETDEWEB)

1990-03-01

Highlights of the Chemical Technology (CMT) Division's activities during 1989 are presented. In this period, CMT conducted research and development in the following areas: (1) electrochemical technology, including high-performance batteries (mainly lithium/iron sulfide and sodium/metal chloride), aqueous batteries (lead-acid and nickel/iron), and advanced fuel cells with molten carbonate and solid oxide electrolytes: (2) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants and the technology for fluidized-bed combustion; (3) methods for recovery of energy from municipal waste and techniques for treatment of hazardous organic waste; (4) nuclear technology related to a process for separating and recovering transuranic elements from nuclear waste and for producing {sup 99}Mo from low-enriched uranium targets, the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor (the Integral Fast Reactor), and waste management; and (5) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for superconducting oxides and associated and ordered solutions at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be administratively responsible for and the major user of the Analytical Chemistry Laboratory at Argonne National Laboratory (ANL).

Chemical technology division: Annual technical report 1987

Energy Technology Data Exchange (ETDEWEB)

1988-05-01

Highlights of the Chemical Technology (CMT) Division's activities during 1987 are presented. In this period, CMT conducted research and development in the following areas: (1) high-performance batteries--mainly lithium-alloy/metal sulfide and sodium/sulfur; (2) aqueous batteries (lead-acid, nickel/iron, etc.); (3) advanced fuel cells with molten carbonate or solid oxide electrolytes; (4) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants and the technology for fluidized-bed combustion; (5) methods for the electromagnetic continuous casting of steel sheet and for the purification of ferrous scrap; (6) methods for recovery of energy from municipal waste and techniques for treatment of hazardous organic waste; (7) nuclear technology related to a process for separating and recovering transuranic elements from nuclear waste, the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor, and waste management; and (8) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of fluid catalysis for converting small molecules to desired products; materials chemistry for liquids and vapors at high temperatures; interfacial processes of importance to corrosion science, high-temperature superconductivity, and catalysis; the thermochemistry of various minerals; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be the major user of the technical support provided by the Analytical Chemistry Laboratory at ANL. 54 figs., 9 tabs.

Chemical Technology Division annual technical report, 1986

International Nuclear Information System (INIS)

1987-06-01

Highlights of the Chemical Technology (CMT) Division's activities during 1986 are presented. In this period, CMT conducted research and development in areas that include the following: (1) high-performance batteries - mainly lithium-alloy/metal sulfide and sodium/sulfur; (2) aqueous batteries (lead-acid, nickel/iron, etc.); (3) advanced fuel cells with molten carbonate or solid oxide electrolytes; (4) coal utilization, including the heat and seed recovery technology for coal-fired magnetohydrodynamics plants, the technology for fluidized-bed combustion, and a novel concept for CO 2 recovery from fossil fuel combustion; (5) methods for recovery of energy from municipal waste; (6) methods for the electromagnetic continuous casting of steel sheet; (7) techniques for treatment of hazardous waste such as reactive metals and trichloroethylenes; (8) nuclear technology related to waste management, a process for separating and recovering transuranic elements from nuclear waste, and the recovery processes for discharged fuel and the uranium blanket in a sodium-cooled fast reactor; and (9) physical chemistry of selected materials in environments simulating those of fission and fusion energy systems. The Division also has a program in basic chemistry research in the areas of catalytic hydrogenation and catalytic oxidation; materials chemistry for associated and ordered solutions at high temperatures; interfacial processes of importance to corrosion science, surface science, and catalysis; the thermochemistry of zeolites and related silicates; and the geochemical processes responsible for trace-element migration within the earth's crust. The Division continued to be the major user of the technical support provided by the Analytical Chemistry Laboratory at ANL. 127 refs., 71 figs., 8 tabs

49 CFR 1242.03 - Made by accounting divisions.

Science.gov (United States)

2010-10-01

... 49 Transportation 9 2010-10-01 2010-10-01 false Made by accounting divisions. 1242.03 Section 1242... accounting divisions. The separation shall be made by accounting divisions, where such divisions are maintained, and the aggregate of the accounting divisions reported for the quarter and for the year. ...

High dynamic range coding imaging system

Science.gov (United States)

Wu, Renfan; Huang, Yifan; Hou, Guangqi

2014-10-01

We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation model and get some simulation images to verify the novel system.

Image Coding Based on Address Vector Quantization.

Science.gov (United States)

Feng, Yushu

Image coding is finding increased application in teleconferencing, archiving, and remote sensing. This thesis investigates the potential of Vector Quantization (VQ), a relatively new source coding technique, for compression of monochromatic and color images. Extensions of the Vector Quantization technique to the Address Vector Quantization method have been investigated. In Vector Quantization, the image data to be encoded are first processed to yield a set of vectors. A codeword from the codebook which best matches the input image vector is then selected. Compression is achieved by replacing the image vector with the index of the code-word which produced the best match, the index is sent to the channel. Reconstruction of the image is done by using a table lookup technique, where the label is simply used as an address for a table containing the representative vectors. A code-book of representative vectors (codewords) is generated using an iterative clustering algorithm such as K-means, or the generalized Lloyd algorithm. A review of different Vector Quantization techniques are given in chapter 1. Chapter 2 gives an overview of codebook design methods including the Kohonen neural network to design codebook. During the encoding process, the correlation of the address is considered and Address Vector Quantization is developed for color image and monochrome image coding. Address VQ which includes static and dynamic processes is introduced in chapter 3. In order to overcome the problems in Hierarchical VQ, Multi-layer Address Vector Quantization is proposed in chapter 4. This approach gives the same performance as that of the normal VQ scheme but the bit rate is about 1/2 to 1/3 as that of the normal VQ method. In chapter 5, a Dynamic Finite State VQ based on a probability transition matrix to select the best subcodebook to encode the image is developed. In chapter 6, a new adaptive vector quantization scheme, suitable for color video coding, called "A Self -Organizing

Quantum computing with Majorana fermion codes

Science.gov (United States)

Litinski, Daniel; von Oppen, Felix

2018-05-01

We establish a unified framework for Majorana-based fault-tolerant quantum computation with Majorana surface codes and Majorana color codes. All logical Clifford gates are implemented with zero-time overhead. This is done by introducing a protocol for Pauli product measurements with tetrons and hexons which only requires local 4-Majorana parity measurements. An analogous protocol is used in the fault-tolerant setting, where tetrons and hexons are replaced by Majorana surface code patches, and parity measurements are replaced by lattice surgery, still only requiring local few-Majorana parity measurements. To this end, we discuss twist defects in Majorana fermion surface codes and adapt the technique of twist-based lattice surgery to fermionic codes. Moreover, we propose a family of codes that we refer to as Majorana color codes, which are obtained by concatenating Majorana surface codes with small Majorana fermion codes. Majorana surface and color codes can be used to decrease the space overhead and stabilizer weight compared to their bosonic counterparts.

Improved Algorithms Speed It Up for Codes

International Nuclear Information System (INIS)

Hazi, A

2005-01-01

Huge computers, huge codes, complex problems to solve. The longer it takes to run a code, the more it costs. One way to speed things up and save time and money is through hardware improvements--faster processors, different system designs, bigger computers. But another side of supercomputing can reap savings in time and speed: software improvements to make codes--particularly the mathematical algorithms that form them--run faster and more efficiently. Speed up math? Is that really possible? According to Livermore physicist Eugene Brooks, the answer is a resounding yes. ''Sure, you get great speed-ups by improving hardware,'' says Brooks, the deputy leader for Computational Physics in N Division, which is part of Livermore's Physics and Advanced Technologies (PAT) Directorate. ''But the real bonus comes on the software side, where improvements in software can lead to orders of magnitude improvement in run times.'' Brooks knows whereof he speaks. Working with Laboratory physicist Abraham Szoeke and others, he has been instrumental in devising ways to shrink the running time of what has, historically, been a tough computational nut to crack: radiation transport codes based on the statistical or Monte Carlo method of calculation. And Brooks is not the only one. Others around the Laboratory, including physicists Andrew Williamson, Randolph Hood, and Jeff Grossman, have come up with innovative ways to speed up Monte Carlo calculations using pure mathematics

Source Code Stylometry Improvements in Python

Science.gov (United States)

2017-12-14

grant (Caliskan-Islam et al. 2015) ............. 1 Fig. 2 Corresponding abstract syntax tree from de-anonymizing programmers’ paper (Caliskan-Islam et...person can be identified via their handwriting or an author identified by their style or prose, programmers can be identified by their code...Provided a labelled training set of code samples (example in Fig. 1), the techniques used in stylometry can identify the author of a piece of code or even

QC-LDPC code-based cryptography

CERN Document Server

Baldi, Marco

2014-01-01

This book describes the fundamentals of cryptographic primitives based on quasi-cyclic low-density parity-check (QC-LDPC) codes, with a special focus on the use of these codes in public-key cryptosystems derived from the McEliece and Niederreiter schemes. In the first part of the book, the main characteristics of QC-LDPC codes are reviewed, and several techniques for their design are presented, while tools for assessing the error correction performance of these codes are also described. Some families of QC-LDPC codes that are best suited for use in cryptography are also presented. The second part of the book focuses on the McEliece and Niederreiter cryptosystems, both in their original forms and in some subsequent variants. The applicability of QC-LDPC codes in these frameworks is investigated by means of theoretical analyses and numerical tools, in order to assess their benefits and drawbacks in terms of system efficiency and security. Several examples of QC-LDPC code-based public key cryptosystems are prese...

Load-balancing techniques for a parallel electromagnetic particle-in-cell code

Energy Technology Data Exchange (ETDEWEB)

PLIMPTON,STEVEN J.; SEIDEL,DAVID B.; PASIK,MICHAEL F.; COATS,REBECCA S.

2000-01-01

QUICKSILVER is a 3-d electromagnetic particle-in-cell simulation code developed and used at Sandia to model relativistic charged particle transport. It models the time-response of electromagnetic fields and low-density-plasmas in a self-consistent manner: the fields push the plasma particles and the plasma current modifies the fields. Through an LDRD project a new parallel version of QUICKSILVER was created to enable large-scale plasma simulations to be run on massively-parallel distributed-memory supercomputers with thousands of processors, such as the Intel Tflops and DEC CPlant machines at Sandia. The new parallel code implements nearly all the features of the original serial QUICKSILVER and can be run on any platform which supports the message-passing interface (MPI) standard as well as on single-processor workstations. This report describes basic strategies useful for parallelizing and load-balancing particle-in-cell codes, outlines the parallel algorithms used in this implementation, and provides a summary of the modifications made to QUICKSILVER. It also highlights a series of benchmark simulations which have been run with the new code that illustrate its performance and parallel efficiency. These calculations have up to a billion grid cells and particles and were run on thousands of processors. This report also serves as a user manual for people wishing to run parallel QUICKSILVER.

Load-balancing techniques for a parallel electromagnetic particle-in-cell code

International Nuclear Information System (INIS)

Plimpton, Steven J.; Seidel, David B.; Pasik, Michael F.; Coats, Rebecca S.

2000-01-01

QUICKSILVER is a 3-d electromagnetic particle-in-cell simulation code developed and used at Sandia to model relativistic charged particle transport. It models the time-response of electromagnetic fields and low-density-plasmas in a self-consistent manner: the fields push the plasma particles and the plasma current modifies the fields. Through an LDRD project a new parallel version of QUICKSILVER was created to enable large-scale plasma simulations to be run on massively-parallel distributed-memory supercomputers with thousands of processors, such as the Intel Tflops and DEC CPlant machines at Sandia. The new parallel code implements nearly all the features of the original serial QUICKSILVER and can be run on any platform which supports the message-passing interface (MPI) standard as well as on single-processor workstations. This report describes basic strategies useful for parallelizing and load-balancing particle-in-cell codes, outlines the parallel algorithms used in this implementation, and provides a summary of the modifications made to QUICKSILVER. It also highlights a series of benchmark simulations which have been run with the new code that illustrate its performance and parallel efficiency. These calculations have up to a billion grid cells and particles and were run on thousands of processors. This report also serves as a user manual for people wishing to run parallel QUICKSILVER

2017 T Division Lightning Talks

Energy Technology Data Exchange (ETDEWEB)

Ramsey, Marilyn Leann [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Abeywardhana, Jayalath AMM [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Colin Mackenzie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Adams, Luke Clyde [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carter, Austin Lewis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ducru, Pablo Philippe [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Duignan, Thomas John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gifford, Brendan Joel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hills, Benjamin Hale [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hoffman, Kentaro Jack [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Khair, Adnan Ibne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Kochanski, Kelly Anne Pribble [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ledwith, Patrick John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leveillee, Joshua Anthony [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lewis, Sina Genevieve [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ma, Xiaoyu [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Merians, Hugh Drake [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moore, Bryan Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nijjar, Parmeet Kaur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Oles, Vladyslav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olszewski, Maciej W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Philipbar, Brad Montgomery [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Reisner, Andrew Ray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Roberts, David Benjamin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rufa, Dominic Antonio [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sifain, Andrew E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Justin Steven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Smith, Lauren Taylor Wisbey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Svolos, Lampros [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thibault, Joshua Ryan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ushijima-Mwesigwa, Hayato Montezuma [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Weaver, Claire Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Witzen, Wyatt Andrew [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Zentgraf, Sabine Silvia [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Alred, John Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-06

All members of the T Division Community, students, staff members, group leaders, division management, and other interested individuals are invited to come and support the following student(s) as they present their Lightning Talks.

Division: The Sleeping Dragon

Science.gov (United States)

Watson, Anne

2012-01-01

Of the four mathematical operators, division seems to not sit easily for many learners. Division is often described as "the odd one out". Pupils develop coping strategies that enable them to "get away with it". So, problems, misunderstandings, and misconceptions go unresolved perhaps for a lifetime. Why is this? Is it a case of "out of sight out…

E-Division activities report

International Nuclear Information System (INIS)

Barschall, H.H.

1979-07-01

This report describes some of the activities in E (Experimental Physics) Division during the past year. E-Division carries out research and development in areas related to the missions of the Laboratory. Many of the activities are in pure and applied atomic and nuclear physics. In addition, this report describes work on accelerators, radiation damage, microwaves, and plasma diagnostics

Code, standard and specifications

International Nuclear Information System (INIS)

Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

2008-01-01

Radiography also same as the other technique, it need standard. This standard was used widely and method of used it also regular. With that, radiography testing only practical based on regulations as mentioned and documented. These regulation or guideline documented in code, standard and specifications. In Malaysia, level one and basic radiographer can do radiography work based on instruction give by level two or three radiographer. This instruction was produced based on guideline that mention in document. Level two must follow the specifications mentioned in standard when write the instruction. From this scenario, it makes clearly that this radiography work is a type of work that everything must follow the rule. For the code, the radiography follow the code of American Society for Mechanical Engineer (ASME) and the only code that have in Malaysia for this time is rule that published by Atomic Energy Licensing Board (AELB) known as Practical code for radiation Protection in Industrial radiography. With the existence of this code, all the radiography must follow the rule or standard regulated automatically.

Computing Challenges in Coded Mask Imaging

Science.gov (United States)

Skinner, Gerald

2009-01-01