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Faculty of Informatics - Papers (Archive)

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Articles 1231 - 1260 of 2013

Full-Text Articles in Physical Sciences and Mathematics

A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, Alfred Mertins Jun 2005

A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, Alfred Mertins

Faculty of Informatics - Papers (Archive)

Although the generation of correlated Rayleigh fading envelopes has been intensively considered in the literature, all conventional methods have their own particular shortcomings, which seriously impedes their applicability. A very general, straightforward algorithm is proposed for the generation of an arbitrary number of Rayleigh envelopes with any desired, equal or unequal power in wireless channels, either with or without Doppler frequency shifts. The proposed algorithm can be applied in the case of spatial correlation, such as with antenna arrays in multiple input multiple output (MIMO) systems, or spectral correlation between random processes, as in orthogonal frequency division multiplexing (OFDM) systems. …

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Design And Preliminary Results Of A Prototype Hts Smes Device, Christopher J. Hawley, S. A. Gower Jun 2005

Design And Preliminary Results Of A Prototype Hts Smes Device, Christopher J. Hawley, S. A. Gower

Faculty of Informatics - Papers (Archive)

The University of Wollongong (UOW) has developed the design for a 20 kJ high transition temperature Superconducting Magnetic Energy Storage (SMES) device, and constructed a nominally 2.5 kJ prototype. The coil for the prototype was wound using High Temperature Superconducting (HTS) BSCCO-2223 tape. It was refrigerated to 20 K using a gaseous helium cold head cryocooler. The SMES device has been constructed as a prototype for a larger commercially realizable system, and hence is capable of supplying a 3-phase load during voltage sags or short (s) power interruptions. This paper discusses the modeling and design of the electromagnetic and thermal …

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Mpeg-21 Digital Item Declaration And Identification-Principles And Compression, I. S. Burnett, S. J. Davis, G. M. Drury Jun 2005

Mpeg-21 Digital Item Declaration And Identification-Principles And Compression, I. S. Burnett, S. J. Davis, G. M. Drury

Faculty of Informatics - Papers (Archive)

At the core of the MPEG-21 Multimedia Framework is the concept of the Digital Item, a virtual container for a hierarchical structure of metadata and resources. This paper considers the Digital Item Declaration Language (DIDL), gives examples of its usage, and discusses how it is used to integrate other parts of MPEG-21. The paper then discusses how Digital Item Identification integrates with the DIDL to allow MPEG-21 to utilize standard identifiers from many application spaces. Finally, an alternative, compressed form of the XML Digital Item Declaration is described. This uses schema-based compression to significantly reduce the size of these XML …

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An Infinite Family Of Goethals-Seidel Arrays, M. Xia, Tianbing Xia, Jennifer Seberry Jun 2005

An Infinite Family Of Goethals-Seidel Arrays, M. Xia, Tianbing Xia, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

In this paper we construct an infinite family of Goethals-Seidel arrays and prove the theorem: If q = 4n - 1 is a prime power = 3(mod 8), then there exists an Hadamard matrix of order 4n of Goethals-Seidel type

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Critical Sets In Orthogonal Arrays With 7 And 9 Levels, R. Saharay, Avishek Adhikari, Jennifer Seberry Jun 2005

Critical Sets In Orthogonal Arrays With 7 And 9 Levels, R. Saharay, Avishek Adhikari, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

To date very few results are known on the critical sets for a set of Mutually Orthogonal Latin Squares(MOLS). In this paper, we consider Orthogonal Array OA(n2, k + 2, n, 2) constructed from k mutually orthogonal cyclic latin squares of order n and obtain bounds on the possible sizes of the minimal critical sets. In particular, for n = 7 we exhibit a critical set, thereby improving the bound reported in Keedwell (1997). The problem is also addressed for n = 9 and a critical set is also presented.

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An Exposure Property Of Block Designs, Y. Wang, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki, L. C. Tran, Y. Zhao, Tianbing Xia Jun 2005

An Exposure Property Of Block Designs, Y. Wang, Jennifer Seberry, Beata J. Wysocki, Tadeusz A. Wysocki, L. C. Tran, Y. Zhao, Tianbing Xia

Faculty of Informatics - Papers (Archive)

An exposure property of block designs is defined and investigated in this paper. The families of c-exposed designs are shown for c = 2 and c = 3. A sufficient condition for a c-exposed design is derived.

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A Construction Technique For Generalized Complex Orthogonal Designs And Applications To Wireless Communications , Jennifer Seberry, S. A. Spence, Tadeusz A. Wysocki Jun 2005

A Construction Technique For Generalized Complex Orthogonal Designs And Applications To Wireless Communications , Jennifer Seberry, S. A. Spence, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

We introduce a construction technique for generalized complex linear processing orthogonal designs, which are p x n matrices X satisfying XHX = f I, where f is a complex quadratic form, I is the identity matrix, and X has complex entries. These matrices generalize the familiar notions of orthogonal designs and generalized complex orthogonal designs. We explain the application of these matrices to space-time block coding for multiple-antenna wireless communications. In particular, we discuss the practical strengths of the space-time block codes constructed via our proposed technique

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Critical Sets For A Pair Of Mutually Orthogonal Cyclic Latin Squares Of Odd Order Greater Than 9, R. Saharay, Avishek Adhikari, Jennifer Seberry Jun 2005

Critical Sets For A Pair Of Mutually Orthogonal Cyclic Latin Squares Of Odd Order Greater Than 9, R. Saharay, Avishek Adhikari, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

To date investigations on critical sets for a set of mutually orthogonal latin squares (MOLS) have been carried out only for small orders less than or equal to 9. In this paper we deal with a pair of cyclic orthogonal latin squares of order n, n greater than or equal to 11, n odd. Through construction of a uniquely completable set we give an upper bound on the size of the minimal critical set. In particular for n = 15 a critical set achieving this bound is obtained.

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On Orthogonal Designs In Order 48, W. H. Holzmann, H Kharaghani, Jennifer Seberry, B. Tayfeh-Rezaie Jun 2005

On Orthogonal Designs In Order 48, W. H. Holzmann, H Kharaghani, Jennifer Seberry, B. Tayfeh-Rezaie

Faculty of Informatics - Papers (Archive)

We show that all 3164 possible OD(48; s1, s2,s3) exist. In addition to the use of some classical techniques we employ two new method of construction.

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A Technological Model To Define Access To Electronic Clinical Records, A. Dalley, J. Fulcher, D. Bomba, K. Lynch, P. Feltham Jun 2005

A Technological Model To Define Access To Electronic Clinical Records, A. Dalley, J. Fulcher, D. Bomba, K. Lynch, P. Feltham

Faculty of Informatics - Papers (Archive)

This communication describes a functioning model that permits access to an electronic health record across a small number of providers resident in an Australian regional setting. Design criteria designated that provider access rights were to be assignable, revokable, transportable, and informable.

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Asterism Decoding For Turbo Coded Mimo Systems, Phillip Conder, Tadeusz A. Wysocki May 2005

Asterism Decoding For Turbo Coded Mimo Systems, Phillip Conder, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

The area of multiple input multiple output (MIMO) communications systems has received enormous attention recently as they can provide a roughly linear increase in data rate by using multiple transmit and receive antennas. MIMO combined with an turbo coding has been shown as a promising way to achieve near capacity for wireless channels. Where previously described decoders provide linear decoding where the number of receive antennas is at least equal to the number of transmit antennas, are computationally burdensome when n/sub t/ > n/sub r/. Asterism decoding is a scheme that achieved ML performance for MIMO systems for any number of …

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Py (Roo): A Fast And Secure Stream Cipher, E. Biham, Jennifer Seberry May 2005

Py (Roo): A Fast And Secure Stream Cipher, E. Biham, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

Py (pronounced Roo, a shorthand for Kangaroo) is a new stream cipher designed especially for the Ecrypt stream cipher contest. It is based on a new kind of primitive, which we call Rolling Arrays. It also uses various other ideas from many types of ciphers, including variable rotations and permutations. In some sense, this design is a kind of a new type of rotor machine, which is specially designed with operations that are very efficient in software. The allowed stream size is 2(to the power 64) bytes in each stream (or 2 (to the power 40) in the smaller version …

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Scalable Multiresolution Color Image Segmentation With Smoothness Constraint, F. Akhlaghian Tab, G. Naghdy, Alfred Mertins May 2005

Scalable Multiresolution Color Image Segmentation With Smoothness Constraint, F. Akhlaghian Tab, G. Naghdy, Alfred Mertins

Faculty of Informatics - Papers (Archive)

This paper presents a multiresolution image segmentation method based on the discrete wavelet transform and Markov random field (MRF) modeling. A major contribution of this work is to add spatial scalability to the segmentation algorithm producing the same segmentation pattern at different resolutions. This property makes it applicable for scalable object-based wavelet coding. The correlation between different resolutions of pyramid is considered by a multire solution analysis which is incorporated into the objective function of the MRF segmentation algorithm. Examining the corresponding pixels at different resolutions simultaneously enables the algorithm to directly segment the images in the YUV or similar …

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Link Redundancy Based Connected Topologies In Ad-Hoc Networks, G. Srivastava, P. Boustead, Joe F. Chicharo May 2005

Link Redundancy Based Connected Topologies In Ad-Hoc Networks, G. Srivastava, P. Boustead, Joe F. Chicharo

Faculty of Informatics - Papers (Archive)

The topology of a wireless network can have a significant impact on the connectivity, fault tolerance and longevity of a network. Power optimised topology control algorithms including a relative neighbourhood graph (RNG) and a minimum spanning tree (MST) reduce the links in a network topology, while keeping a topology connected. Link redundancy may be critical to cope with faults such as node failures and link disruptions. In this paper, we analyse the fault tolerance of a number of topology control algorithms. We propose a new distributed mechanism to increase the fault tolerance of power optimised topology control algorithms. The proposed …

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Generalized Analysis Model For Fringe Pattern Profilometry, Y. Hu, Jiangtao Xi, Z. Yang, Enbang Li, Joe F. Chicharo May 2005

Generalized Analysis Model For Fringe Pattern Profilometry, Y. Hu, Jiangtao Xi, Z. Yang, Enbang Li, Joe F. Chicharo

Faculty of Informatics - Papers (Archive)

In this paper, a generalized analysis model for fringe pattern profilometry is presented. The new analysis model is derived mathematically, which describes the essential relationships between projected and deformed fringe patterns. With generalized analysis model, the projected fringe patterns used for profilometry can be arbitrary rather than being limited to be sinusoidal as those for the conventional approaches. Meanwhile, based on the proposed generalized model, a new algorithm is presented to reconstruct three-dimensional surfaces. Computer simulation results show that compared with the conventional model for fringe pattern profilometry, the generalized model and the proposed algorithm can significantly improve the three-dimensional …

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Efficient Training Algorithms For A Class Of Shunting Inhibitory Convolutional Neural Networks, Fok Hing Chi Tivive, Abdesselam Bouzerdoum May 2005

Efficient Training Algorithms For A Class Of Shunting Inhibitory Convolutional Neural Networks, Fok Hing Chi Tivive, Abdesselam Bouzerdoum

Faculty of Informatics - Papers (Archive)

This article presents some efficient training algorithms, based on first-order, second-order, and conjugate gradient optimization methods, for a class of convolutional neural networks (CoNNs), known as shunting inhibitory convolution neural networks. Furthermore, a new hybrid method is proposed, which is derived from the principles of Quickprop, Rprop, SuperSAB, and least squares (LS). Experimental results show that the new hybrid method can perform as well as the Levenberg-Marquardt (LM) algorithm, but at a much lower computational cost and less memory storage. For comparison sake, the visual pattern recognition task of face/nonface discrimination is chosen as a classification problem to evaluate the …

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On Adaptive And Online Data Integration, J. R. Getta Apr 2005

On Adaptive And Online Data Integration, J. R. Getta

Faculty of Informatics - Papers (Archive)

The recent works on integration of large database systems distributed over wide-area networks concentrate on the adaptive and online techniques. Online property of data integration means continuous integration of transmitted data with the already available results. Adaptivity materializes in a form of dynamic adjustments to the data integration plans in a response to the recent characteristics of data transmission. Implementation of adaptive and online data integration needs the specialized systems of operations and transformations of integration plans. This paper describes a new class of elementary operations on increments and/or decrements of data and shows how to express data integration plans …

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A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Radio Channels, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, Alfred Mertins Apr 2005

A Generalized Algorithm For The Generation Of Correlated Rayleigh Fading Envelopes In Radio Channels, Le Chung Tran, Tadeusz A. Wysocki, Jennifer Seberry, Alfred Mertins

Faculty of Informatics - Papers (Archive)

Although generation of correlated Rayleigh fading envelopes has been intensively considered in the literature, all conventional methods have their own shortcomings, which seriously impede their applicability. In this paper, a very general, straightforward algorithm for generation of an arbitrary number of Rayleigh envelopes with any desired, equal or unequal power, in wireless channels either with or without Doppler frequency shifts, is proposed. The proposed algorithm can be applied in case of spatial correlation, such as with antenna arrays in Multiple Input Multiple Output (MIMO) systems, or spectral correlation between the random processes like in Orthogonal Frequency Division Multiplexing (OFDM) systems. …

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Power Quality (Pq) Survey Reporting: Discrete Disturbance Limits, H. M. Herath, V. J. Gosbell, S. Perera Apr 2005

Power Quality (Pq) Survey Reporting: Discrete Disturbance Limits, H. M. Herath, V. J. Gosbell, S. Perera

Faculty of Informatics - Papers (Archive)

iscrete or event type power quality (PQ) disturbances mainly include voltage sags, swells, and the transients. An extensive literature survey suggests that there is no generally accepted method for characterization of these disturbances and suitable limits are not yet found in any international standard. One of the reasons for the lack of characterization methods is the difficulty of defining suitable site indices for each discrete disturbance type. In this paper existing characterization methods are reviewed and discussed. A new generalized approach is then given to show a better way of characterizing voltage sags, swells and transients. This is followed by …

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Co Valence And Possible Spin Transformation In Diluted Magnetic Semiconductors Zn/Sub 1-Z/Mg/Sub Z/Co/Sub 0.15/O And Zn/Sub 1-X/Co/Sub X/O, Germanas Peleckis, X. L. Wang, R. S. Liu, S X. Dou Apr 2005

Co Valence And Possible Spin Transformation In Diluted Magnetic Semiconductors Zn/Sub 1-Z/Mg/Sub Z/Co/Sub 0.15/O And Zn/Sub 1-X/Co/Sub X/O, Germanas Peleckis, X. L. Wang, R. S. Liu, S X. Dou

Faculty of Informatics - Papers (Archive)

In this paper, possible spin transformation and Co valence in dilute magnetic semiconductors is studied. Polycrystalline samples of Zn/sub 1-x/Co/sub x/O (0.05/spl les/x/spl les/0.17) and Zn/sub 1-z/Mg/sub z/Co/sub 0.15/O are prepared by rapid oxalate decomposition technique. X-ray diffraction is used to determine phase purity of the samples. Co valence state 2+ is determined by X-ray absorption near edge spectroscopy (XANES) using synchrotron irradiation. Magnetic properties measured show that all samples are paramagnetic and magnetization hysteresis measurement indicated that there is no trace of ferromagnetism. From Curie-Weiss fittings at high temperature region, the effective magnetic moment (/spl mu//sub eff/) is 3.87/spl …

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Personal Firewall For Pocket Pc 2003: Design & Implementation, Willy Susilo, R. J. Ang, C. A. Mcdonald, J. Huang Mar 2005

Personal Firewall For Pocket Pc 2003: Design & Implementation, Willy Susilo, R. J. Ang, C. A. Mcdonald, J. Huang

Faculty of Informatics - Papers (Archive)

Personal digital assistants (PDAs) are widely used and becoming indispensable tools of everyday life. Wired or wireless connection enables PDA users to connect to the Internet from any place, making security an extremely important issue in a pervasive computing environment. This paper investigates how to build a personal firewall for PDAs running Pocket PC 2003. This personal firewall allows the PDA user to perform access control based on a user-defined policy, and hence provides a security perimeter between the public network and the PDA. We provide a complete technical detail on how the firewall can be built in a Pocket …

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Privacy-Enhanced Internet Storage, Willy Susilo, Fangguo Zhang, Yi Mu Mar 2005

Privacy-Enhanced Internet Storage, Willy Susilo, Fangguo Zhang, Yi Mu

Faculty of Informatics - Papers (Archive)

One of the main important uses of Internet is its ability to connect people through the use of email or Internet storage. However, it is often desirable to limit the use of email or Internet storage clue to organization's restriction, avoiding spams, etc. In this paper, we propose cryptographic schemes that can be used to stop unwanted messages to be stored in the Internet server. We refer this technique as privacy enhancement for Internet storage, since the Internet server will not learn any information directed to its users, other than performing its task to deliver or stop the messages. Firstly, …

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Virtual Cochlear Implant Insertion For Medical Education, C. Todd, F. Naghdy Mar 2005

Virtual Cochlear Implant Insertion For Medical Education, C. Todd, F. Naghdy

Faculty of Informatics - Papers (Archive)

A surgical simulator has been developed for the purpose of training otologists in cochlear implantation. The simulation provides real-time visual and haptic feedback during implant insertion into the human Scala Tympani (ST). The benefits and possible outcomes for this type of simulator are presented. Methods for model generation are discussed, for anatomical and prosthetic structures used in the simulation. Development of the interactive model with force-feedback is presented, with results.

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Values Of Minors Of Some Infinite Families Of Matrices Constructed From Supplementary Difference Sets And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry Mar 2005

Values Of Minors Of Some Infinite Families Of Matrices Constructed From Supplementary Difference Sets And Their Application To The Growth Problem, C. Koukouvinos, M. Mitrouli, Jennifer Seberry

Faculty of Informatics - Papers (Archive)

We obtain explicit formulae for the values of the 2v - j minors, j = 0,1, 2 of (1, -1) matrices of order 2v, v odd, where the matrix is constructed using two circulant or type 1 incidence matrices of 2— {v; k1, k2, λ} sds. This allows us to obtain information on the growth problem for families of matrices with moderate growth. Some of our theoretical formulae imply growth close to the order 2v but experimentation has not yet supported this result. An open problem remains to establish whether the (1, -1) CP incidence matrices of certain SBIBDs, can …

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Microchipping People: The Rise Of The Electrophorus, Katina Michael, M G. Michael Mar 2005

Microchipping People: The Rise Of The Electrophorus, Katina Michael, M G. Michael

Faculty of Informatics - Papers (Archive)

Automatic identification (auto-ID) is the process of identifying a living or nonliving thing without direct human intervention. Before auto-ID only manual identification techniques existed, such as tattoos and fingerprints, which did not allow for the automatic capture of data. Many researchers credit the vision of a cashless society to the capabilities of auto-ID. Since the 1960s automatic identification has proliferated especially for mass-market applications such as electronic banking and citizen ID. Together with increases in computer processing power, storage equipment and networking capabilities, miniaturization and mobility have heightened the significance of auto-ID to e-business, especially mobile commerce. Citizens are now …

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Performance Of Convolutional Interleavers With Different Spacing Parameters In Turbo Codes, Sina Vafi, Tadeusz A. Wysocki Feb 2005

Performance Of Convolutional Interleavers With Different Spacing Parameters In Turbo Codes, Sina Vafi, Tadeusz A. Wysocki

Faculty of Informatics - Papers (Archive)

This paper considers application of a convolutional interleaver and the issue of influence of the space parameter in the turbo code performance. Similarly to previously considered convolutional interleavers, the new interleavers are designed as block interleavers and their performance in different code structures is compared with the interleaver having higher periods and space value of 1. In each comparison, the number of inserted stuff bits at the end of each data block is considered to be of similar order. Finally, suitable modification to the new interleavers is proposed improving performance for the codes with lower number of stuff bits.

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A Closed-Form Exact Solution For The Value Of American Put And Its Optimal Exercise Boundary, Song-Ping Zhu Jan 2005

A Closed-Form Exact Solution For The Value Of American Put And Its Optimal Exercise Boundary, Song-Ping Zhu

Faculty of Informatics - Papers (Archive)

Searching for a closed-form exact solution for American put options under the Black-Scholes framework has been a long standing problem in the past; many researchers believe that it is impossible to find such a solution. In this paper, a closed-form exact solution, in the form of a Taylor's series expansion, of the well-known Black-Scholes equation is presented for the first time. As a result of this analytic solution, the optimal exercise boundary, which is the main difficulty of the problem, is found as an explicit function of the risk-free interest rate, the volatility and the time to expiration.

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Development Of Empirical Relationships For Metallurgical Design Of Hot-Rolled Steel Products, Timothy R. Marchant, Alysha Nickerson, David Scott, Steve Taylor Jan 2005

Development Of Empirical Relationships For Metallurgical Design Of Hot-Rolled Steel Products, Timothy R. Marchant, Alysha Nickerson, David Scott, Steve Taylor

Faculty of Informatics - Papers (Archive)

An empirical model is developed to predict the mechanical properties that steel inherits from the hot-rolling process and its chemical composition. In this process, slabs of steel are heated and rolled into thinner sheets which are either coiled or cut into plates. The mechanical properties of the coils and plates are sampled and must conform to national and international standards for steel products. The aim here is to use the statistical technique of multiple linear regression to develop relationships between the mechanical properties and the various processing temperatures and concentrations of chemical elements present in the steel. This analytical tool …

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Bifurcation Phenomena For An Oxidation Reaction In A Continuously Stirred Tank Reactor. Iii The Inhibiting Effect Of An Inert Species, Mark Nelson Jan 2005

Bifurcation Phenomena For An Oxidation Reaction In A Continuously Stirred Tank Reactor. Iii The Inhibiting Effect Of An Inert Species, Mark Nelson

Faculty of Informatics - Papers (Archive)

We extend an investigation into the static and dynamic multiplicity exhibited by the reaction of a fuel/air mixture in a continuously stirred tank reactor by considering the effect of adding a chemically inert species to the reaction mixture. The primary bifurcation parameter is taken to be the fuel fraction as this is the most important case from the perspective of fire-retardancy. We show how the addition of the inert species progressively changes the steady-state diagrams and flammability limits. We also briefly outline how heat-sink additives can be incorporated into our scheme.

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Improving Bioreactor Performance: Are Two Cstbs Always Better Than One?, Harvinder Sidhu, Mark Nelson Jan 2005

Improving Bioreactor Performance: Are Two Cstbs Always Better Than One?, Harvinder Sidhu, Mark Nelson

Faculty of Informatics - Papers (Archive)

We investigate a bioreactor cascade consisting of two reactors. For a given total residence time, we study how the performance of the reactor (measured either as the cell mass concentration or the reactor productivity) depends upon the feed substrate concentration and the residence time in the first reactor. The bioreactor model in this study uses a growth rate that is given by a Monod expression with a yield coefficient that is a linear function of the substrate concentration. Previous researchers have compared the performance o f a two-reactor system against a single reactor with the same total residence time. The …

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