Parallel Combinatory Research Articles

Multidimensional parallel combinatory transform domain communication system

SummaryTransform domain communication system is an adaptive anti‐interference system that can dynamically generate interference‐orthogonal waveforms. As a spread spectrum system, its low spectrum efficiency limits potential practical applications. In TDCS, cyclic code shift keying is an orthogonal modulation, whose symbols can be regarded as scalars in different dimensions. However, the constellation is restricted by signal time‐bandwidth product. In this study, extending constellation is proven to be a valid approach to improve spectrum efficiency. The combinatory of multidimensional vectors is designed mathematically to increase the variety of the scalars with the minimum orthogonality damage. On the basis of the design, an efficient modulation scheme, namely, multidimensional parallel combinatory transform domain communication system, is proposed, whose fundamental modulation symbols can be represented by the combinatory of a series of cyclic code shift keying symbols with phase shift keying modulation. Compared with the existing methods, multidimensional parallel combinatory transform domain communication system can achieve a considerably higher spectrum efficiency. The bit error rate performance is also improved to various extents. Theoretical spectrum efficiency and bit error rate of the proposed method are derived for additive white Gaussian noise and typical multipath fading channels. System with different spectral conditions and channel estimation methods is also simulated and analyzed to confirm the practical usability.

Performance of CZT-assisted parallel combinatory multicarrier Frequency-Hopping Spread Spectrum over shallow underwater acoustic channels

A Parallel Combinatory multicarrier Frequency-Hopping Spread Spectrum (PC/MC-FHSS) Underwater Acoustic (UWA) communication system combined with a Chip-z Transform (CZT) method is proposed in this paper. One of the advantages of the PC/MC-FHSS system is its ability to resist fading and random narrowband interference during transmission over the UWA channel. Another benefit is increasing the data rate of the system. Results of computer simulations and pool experiments prove that the proposed CZT-assisted PC/MC-FHSS communication system exhibits greater BER performance and higher data rate than those of the traditional FHSS system and the PC/MC-FHSS system. Outfield experiments carried out in Xiamen Port show that the BER performance of the system is on the order of 10−3, when the data rate is up to 469bps and the distances of the communication systems is 10km.

Massively Parallel Combinatorial Screening

Genetic Engineering & Biotechnology NewsVol. 35, No. 13 Bioprocessing TutorialMassively Parallel Combinatorial ScreeningWell-Known Technique Can Significantly Improve the Production of BiotherapeuticsDiana HernandezDiana HernandezDiana Hernandez, Ph.D. (E-mail Address: diana@plasticell.co.uk), is principal scientist at Plasticell. Website: www.plasticell.co.uk.Search for more papers by this authorPublished Online:26 Jun 2015https://doi.org/10.1089/gen.35.13.15AboutSectionsView articleView Full TextPDF/EPUB Permissions & CitationsPermissionsDownload CitationsTrack CitationsAdd to favorites Back To Publication ShareShare onFacebookTwitterLinked InRedditEmail View articleFiguresReferencesRelatedDetails Volume 35Issue 13Jul 2015 Information© 2015 by GEN PublishingTo cite this article:Diana Hernandez.Massively Parallel Combinatorial Screening.Genetic Engineering & Biotechnology News.Jul 2015.28-29.http://doi.org/10.1089/gen.35.13.15Published in Volume: 35 Issue 13: June 26, 2015PDF download

Extension of Parallel Combinatory Multicode Transmission with Constant-Amplitude Signaling and Its Theoretical Analysis

Extension of Parallel Combinatory Multicode Transmission with Constant-Amplitude Signaling and Its Theoretical Analysis

A Parallel Combinatory OFDM System with Weighted Phase Subcarriers

Orthogonal Frequency Division Multiplexing (OFDM) is usually regarded as a spectral efficient multicarrier modulation technique, yet it suffers from a high peak-to-average power ratio (PAPR) problem. Among all the existing PAPR reduction techniques in OFDM systems, side information based PAPR reduction techniques such as partial transmit sequence (PTS) and selective mapping (SLM) schemes, have attracted the most attention. However, the transmission of side information results in somewhat spectral loss and this does not significantly improve the bit error rate (BER) performance. Parallel combinatory (PC) OFDM yields higher spectral efficiency (SE) and better BER performance on Gaussian channels,while is a little but not obvious PAPR improvement over the ordinary OFDM system. This investigation aimed to design a ?perfect? OFDM system. We introduce the side information to rotate the subcarrier phases of our novel PC-OFDM system structure, and call this new system the SIPC(Side information based Parallel Combinatory)-OFDM system. The proposed system achieves better PAPR and SE performance. In addition, considering the tradeoff of system parameters, the proposed system also has the properties of a higher BER.

New OFDM structure with parallel combinatory code

We have introduced a flexible OFDM structure based on a promising property of IFFT operation. This structure can support uplink applications which include many transmitters using different numbers of subcarriers and one receiver with just one IFFT/FFT module with the subcarriers of the least common multiple (LCM) for the number of subcarriers of all the transmitters. In this paper, combining the parallel combinatory (PC) code and the proposed flexible OFDM structure, we report the design of a new OFDM system with PC code for various applications with a moderate transmission rate. The system can select appropriate phase sets for all modulated subcarriers for each PC code for different design requirements such as peak-to-average power ratio (PAPR) reduction or BER performance improvement. The proposed system will achieve better PAPR characteristics and promising BER performance. In addition, due to the flexible OFDM structure, the proposed PC-OFDM system will also have properties of high adaptability and compatibility.

A Novel Modulation with Parallel Combinatory and High Compaction Multi-Carrier Modulation

In this paper, we propose a new modulation named parallel combinatory/high compaction multi-carrier modulation (PC/HC-MCM) using the techniques of parallel combinatory orthogonal frequency division multiplexing (PC-OFDM) and high compaction multi-carrier modulation (HC-MCM). Two types of PC/HC-MCM systems, which are named as modulated PC/HC-MCM system and (unmodulated) PC/HC-MCM system, can be designed. The modulated PC/HC-MCM system achieves better bit-error rate (BER) performance than that of HC-MCM system with equal bandwidth efficiency (BWE). The PC/HC-MCM system can obtain the better peak-to-average power ratio (PAPR) characteristics by selecting appropriate constellation for each subcarrier. On the other hand, since PC/HC-MCM can divide the PC-OFDM symbol duration into multiple time-slots, the advantages of frequency hopping (FH) can be applied in the PC/HC-MCM system. Therefore, we also combine the PC/HC-MCM and frequency hopping multiple access (FHMA) to propose a novel multiple access (MA) system. It can simultaneously transmit multiple users' data within one symbol duration of PC-OFDM.

Resolving Racemic Mixtures Using Parallel Combinatorial Libraries

AbstractFor Abstract see ChemInform Abstract in Full Text.

Solvent effects on the screening of parallel combinatorial libraries for selectors for chiral chromatography.

The correlation between the resin-swelling property and the outcome of the crucial equilibration assay used in our parallel library screening method is investigated. It is found that the incorporation of CHCl3 (an effective swelling solvent for both the polystyrene and TentaGel resins) into the equilibration solvent leads to faster equilibration and thus shorter library screening time. The outcome of the equilibration experiment is also found to depend on the chemical nature of the solid base resins. It appears that polystyrene resin, which has a relatively inert surface, provides higher enantioselectivity than the polar TentaGel resin. The importance of a thoroughly swelled resin for the direct assay of functional groups on the resin is demonstrated.

Resolving racemic mixtures using parallel combinatorial libraries.

Resolving racemic mixtures using parallel combinatorial libraries.

Identification of chiral selectors from a 200-member parallel combinatorial library.

Selection of chiral selectors for the resolution of racemic N-(1-naphthyl)leucine ester 1 was studied with a 200-member parallel library prepared on polymeric synthesis resin. Through this study, the library screening procedure developed previously is improved and other pertinent issues concerning the screening process are also addressed. The equilibration time required for screening is reduced from 24 h to approximately 3 h. Excellent correlation of the outcome between the resin batch equilibration experiment and chromatographic separation is further demonstrated. It is also demonstrated that selectors with separation factors as low as 1.4 could be identified by this batch screening process. In addition, a great deal of information regarding enantioselective interactions was obtained in this parallel library study. Such information should prove useful in improving future library designs.

Screening of a Parallel Combinatorial Library for Selectors for Chiral Chromatography

A method to screen parallel combinatorial libraries for chiral selectors is described. Crucial elements to such an approach are the efficient syntheses of potential chiral selectors on synthesis resins and the rapid screening of selectors attached to these resins with circular dichroism measurement. The method does not require any immobilization of the analyte and could complement the mixture combinatorial library method developed earlier in this laboratory. The feasibility of this parallel library screening procedure is demonstrated with a model study of the chiral HPLC resolution of (1-naphthyl)leucine ester (1) using a 16-member small library.

Exercises in Parallel Combinatorial Computing.

Exercises in Parallel Combinatorial Computing.

Exercises in Parallel Combinatorial Computing

"Exercises in Parallel Combinatorial Computing." Journal of the Operational Research Society, 44(4), pp. 415–416