Orthogonal design

Antenna spacings, the angle spread and the Rice factor significantly affect the correlation of fading coefficients in a multi-antenna system. In this paper we study the effect of these parameters on the performance of different types of detection schemes in a BLAST architecture. We show that the detection method based on lattice decoding is more resistant to the correlated fading than other types of detection which work based on successive interference cancellation. We notice that highly correlated fades significantly degrade the performance of detection techniques based on successive interference cancellation whereas they slightly affect the lattice decoding algorithm. We also study the effects of correlated fades on some space-time block codes. We show that space-time block codes from orthogonal design are more resistant to correlation than other high rate linear space-time block codes.

Constructions of square, maximum rate complex orthogonal space-time block codes (CO STBCs) are well known, however codes constructed via the known methods include numerous zeros, which impede their practical implementation. By modifying the Williamson and Wallis-Whiteman arrays to apply to complex matrices, we propose two methods of construction of square, order-4n CO STBCs from square, order-n codes which satisfy certain properties. Applying the proposed methods, we construct square, maximum rate, order-8 CO STBCs with no zeros, such that the transmitted symbols are equally dispersed through transmit antennas. Those codes, referred to as the improved square CO STBCs, have the advantages that the power is equally transmitted via each transmit antenna during every symbol time slot and that a lower peak-to-average power ratio (PAPR) is required to achieve the same bit error rates as the conventional CO STBCs with zeros. C OMPLEX orthogonal space-time block codes (CO STBCs) have been intensively examined, as they provide large transmit diversity and increase the capacity of wireless channels, while requiring a very simple maximum likelihood (ML) decoding method [3]- . A CO STBC over variables is corresponding to transmit (Tx) antennas, decoding delay (or memory length) of , rate and is denoted as CO STBC. Given and , the goal is to minimize the decoding delay . Hence, square CO STBCs are particularly interesting because they require the minimum Manuscript

Skew-Hadamard matrices are of special interest due to their use, among others, in constructing orthogonal designs. In this paper, we give a survey on the existence and equivalence of skew-Hadamard matrices. In addition, we present some new skew-Hadamard matrices of order 52 and improve the known lower bound on the number of the skew-Hadamard matrices of this order.

In the present study, laser cutting of cotton fiber composite laminate is experimented using a modified DVD writer drive. A 250 mW diode laser is initially extracted from a DVD writer drive, and then regulated by a custom-made laser driver circuit designed using a Proteus® software. Experimental tests are carried out using multi-pass laser trepanning drilling at different drilling speeds and standoff distances (SODs). The cut quality is evaluated by measuring the extent of both oxide and resolidified resin regions. It was discovered high speed of trepanning drilling and positive SOD significantly improve cutting region quality. Furthermore, positive and negative SODs require relatively high number of passes at different drilling speeds. From SEM micrographs, it is found out that the crack formation and fiber protruding happen in thedrilling area due to thermal stresses and matrix vaporization.

The allocation of combinations of attribute levels to choice situations in stated choice (SC) experiments can have a significant influence upon the resulting study outputs once data is collected. Recently, a small but growing stream of research has looked at using what have become known as efficient SC experimental designs to allocate the attribute levels to choice situations in a manner designed to produce better model outcomes. This research stream has shown that the use of efficient SC designs can lead to improvements in the reliability of parameter estimates derived from discrete choice models estimated on SC data for a given sample size. Unlike orthogonal designs, however, efficient SC experiments are generated in such a manner that their efficiency is related to the econometric model that is most likely to be estimated once the choice data is collected. To date, most of the research on efficient SC designs has assumed an MNL model format. In this paper, we generate efficient SC experiments for nested logit models and compare and contrast these with designs specifically generated assuming an MNL model form. We find that the overall efficiency of the design is maximized only when the model assumed in generating the design is the model that is fitted during estimation.

Symmetric designs are used to construct binary extremal self-dual codes and Hadamard matrices and weighing matrices are used to construct extremal ternary self-dual codes. In this paper, we consider orthogonal designs and related matrices to construct self-dual codes over a larger alphabet. As an example, a number of extremal Type II codes over Z 2k are constructed.

A single-carrier quasi-orthogonal distributed block space-time coding scheme for a wireless collaborative network with one relaying stage composed of four nodes is proposed. This block quasi-orthogonal design can attain full diversity and maximum rate, and is based on simple amplify-and-forward processing at the relay nodes. A cyclic prefix is introduced into the block transmission to overcome channel delay mismatches in the paths through the four relays. In single-carrier operation, these delays are shown to introduce inter-symbol-interference (ISI) in the destination signal. A linear pre-processing scheme is therefore designed to mitigate this ISI through maximizing signal-to-interference-plus-noise ratio (SINR) at the receiver in combination with iterative equalization. To reduce the computational complexity of this scheme the underlying interference matrices are rendered sparse by the pre-processing operation. Simulation studies confirm the improvement in SINR of the proposed ap...

This paper describes the dynamic investigation of a 3-component and a 6-component force- moment sensors using the facilities in the PTB (Physikalisch-Technische Bundesanstalt) in Germany. The 3-component sensor has the transverse forces Fx and Fy of each having 200 N capacity and a twisting moment Mz of 10 Nm capacity and the 6-component sensor has force components Fx, Fy and Fy each having 200 N capacity and moment components Mx, My and Mz each having 20 Nm capacity. The sensitivity of the sensors decreases as the frequency increases and the sensors show almost 90 o symmetry due to their geometry.

We show that the classical algebra of quaternions is a commutative Z 2 ×Z 2 ×Z 2 -graded algebra. A similar interpretation of the algebra of octonions is impossible. This note is our "private investigation" of what really happened on the 16th of October, 1843 on the Brougham Bridge when Sir William Rowan Hamilton engraved on a stone his fundamental relations: Since then, the elements i, j and k, together with the unit, 1, denote the canonical basis of the celebrated 4-dimensional associative algebra of quaternions H. Of course, the algebra H is not commutative: the relations above imply that the elements i, j, k anticommute with each other, for instance Yes, but...

The success of applying generalized complex orthogonal designs as space-time block codes recently motivated the definition of quaternion orthogonal designs as potential building blocks for space-timepolarization block codes. This paper offers techniques for constructing quaternion orthogonal designs via combinations of specially chosen complex orthogonal designs. One technique is used to build quaternion orthogonal designs on complex variables for any even number of columns. A second related technique is applied to maximum rate complex orthogonal designs to generate an infinite family of quaternion orthogonal designs on complex variables such that the resulting designs have no zero entries. This second technique is also used to generate an infinite family of quaternion orthogonal designs defined over quaternion variables that display a regular redundancy. The proposed constructions are theoretically important because they provide the first known direct techniques for building infinite families of orthogonal designs over quaternion variables for any number of columns.

Nonregular fractional factorial designs such as Plackett-Burman designs and other orthogonal arrays are widely used in various screening experiments for their run size economy and flexibility. The traditional analysis focuses on main effects only. Hamada and Wu (1992) went beyond the traditional approach and proposed an analysis strategy to demonstrate that some interactions could be entertained and estimated beyond a few significant main effects. Their groundbreaking work stimulated much of the recent developments in design criterion creation, construction and analysis of nonregular designs. This paper reviews important developments in optimality criteria and comparison, including projection properties, generalized resolution, various generalized minimum aberration criteria, optimality results, construction methods and analysis strategies for nonregular designs.

Apple juice inoculated with Staphylococcus aureus (SST 2.4) was processed by a hurdle sequence including ultraviolet irradiation (UV; 30 min, 20 °C), pre-heating and pulsed electric fields (PEF). Four different levels of pre-heating temperature (35-50 °C), electric field strength (28-40 kV cm À1 ) and total treatment time (25-100 ls), were used in an orthogonal design, evaluating their impact on S. aureus. Selected physical and chemical quality attributes were measured and compared to conventional pasteurisation (26 s, 94 °C). A higher reduction (P < 0.05) of S. aureus was achieved with a hurdle approach (UV; 46 °C (PEF inlet) and 58 °C (PEF outlet); PEF 40 kV cm À1 and 100 ls) in comparison to conventional pasteurisation (9.5 vs. 8.2 log 10 , respectively). Bacterial inactivation was not affected by pre-heating temperature (P P 0.05), while increasing electric field strength and treatment time both induced a reduction in bacterial numbers (P < 0.05). An analysis of the normalised energy densities for all UV/PEF processing conditions indicated a maximised energy efficiency at higher electric field strengths and shorter treatment times. Treatments showed little effect on the measured quality attributes.

Apple juice inoculated with Staphylococcus aureus (SST 2.4) was processed by a hurdle sequence including ultraviolet irradiation (UV; 30 min, 20 °C), pre-heating and pulsed electric fields (PEF). Four different levels of pre-heating temperature (35-50 °C), electric field strength (28-40 kV cm À1 ) and total treatment time (25-100 ls), were used in an orthogonal design, evaluating their impact on S. aureus. Selected physical and chemical quality attributes were measured and compared to conventional pasteurisation (26 s, 94 °C). A higher reduction (P < 0.05) of S. aureus was achieved with a hurdle approach (UV; 46 °C (PEF inlet) and 58 °C (PEF outlet); PEF 40 kV cm À1 and 100 ls) in comparison to conventional pasteurisation (9.5 vs. 8.2 log 10 , respectively). Bacterial inactivation was not affected by pre-heating temperature (P P 0.05), while increasing electric field strength and treatment time both induced a reduction in bacterial numbers (P < 0.05). An analysis of the normalised energy densities for all UV/PEF processing conditions indicated a maximised energy efficiency at higher electric field strengths and shorter treatment times. Treatments showed little effect on the measured quality attributes.

In this paper, the prediction of a soot model [J. Appel, H. Bockhorn, M. Frenklach, Combust. Flame 121 (2000) 122-136] is compared to a recently published set of highly detailed soot particle size distributions [B. Zhao, Z. Yang, Z. Li, M.V. Johnston, H. Wang, Proc. Combust. Inst. 30 (2005)]. A stochastic approach is used to obtain soot particle size distributions (PSDs). The key features of the measured and simulated particle size distributions are identified and used as a simple way of comparing PSDs. The sensitivity of the soot PSDs to the parameters defining parts of the soot model, such as soot inception, particle and PAH collision efficiency and enhancement, and surface activity is investigated. Incepting soot particle size is found to have a very significant effect on the small-size end of the PSDs, especially the position of the trough for a bimodal soot PSDs. A new model for the decay in the surface activity is proposed in which the activity of the soot particle depends only on the history of that particle and the local temperature in the flame. This is a first attempt to use local flame variables to define the surface aging which has major impact on the prediction of the large-size end of the PSDs. Using these modifications to the soot model it is possible to improve the agreement between some of the points of interest in the simulated and measured PSDs. The paper achieves the task to help advance the soot models to predict soot PSD in addition to soot volume fraction and number density, which has been the focus of the literature.

Common ratio-based approaches for analyzing gene expression microarray data do not provide a framework for handling replication, although replication is clearly desirable for these noisy data. In contrast, replication fits naturally into analysis of variance (ANOVA) methods. We use ANOVA to analyze data from a microarray experiment to compare gene expression in drug-treated and control cells lines. We discuss issues that commonly arise in the analysis of microarray data, and present practical solutions to some common problems.

This article describes and illustrates how to produce modular .NET software solutions by the use of Decorator design pattern and AspectOriented Programming (AOP) tool PostSharp. We applied both techniques for modularizing crosscutting concerns of a traditional modularization example: logging function. This work presents logging solutions with the use of Decorator and PostSharp to modularize associated cross issues, along with detailing the advantages and disadvantages of both solutions. Likewise, this work points out details of in PostSharp along with proposing the use of PostSharp and Decorator to achieve solutions with a higher level of modularity.

Ultraviolet-visible (UV-VIS) and near-infrared (NIR) spectroscopy coupled to artificial neural networks (ANNs) was used as a nondestructive technique to quantify ethanol, glucose, glycerol, tartaric acid, malic acid, acetic acid and lactic acid in aqueous mixtures. Spectral data were obtained for 152 samples. Differing pre-treatments were applied to the spectra and ANN models were obtained using raw and pre-treated data to evaluate several spectral wavelength groupings and ANN training conditions. Feasible calibration models were obtained for ethanol, malic acid and tartaric acid. To validate the process, 120 new samples were measured using the best ANN models. The determination coefficients for the three compounds using this validation set were above 0.9. The results showed the importance of good parameter selection when training the ANN to obtain reliable models. Coupling UV-VIS-NIR spectroscopy to ANN could provide an alternative to conventional chemical methods for determining ethanol, tartaric acid and malic acid in wines.

Wireless communication system is rapidly enhancing using various techniques by many researcher & to meet the requirement of accurate and fast data communication in fading environment. The MIMO technique plays an important role in this direction. It allows upto provide higher order modulation for maintaining the errors in limits. This paper describes one of the MIMO techniques namely orthogonal space time block code. This technique improves the BER of the QAM-16,QAM-32 and QAM-64 based communication in Rayleigh fading environment. The result shows an improvement in the BER.

In this paper, we consider efficient blind decoder design for orthogonal space-time block codes (OSTBCs). A general decision rule for blind OSTBC decoding is derived assuming a quasi-static flat multiple-input multiple-output (MIMO) Rayleigh fading channel. We use the linear dispersion representation of OSTBCs to derive a blind decoder that results in a quadratic minimization problem, which can be solved efficiently by semidefinite relaxation, sphere decoding or successive interference cancellation. To resolve phase ambiguity problems inherent in blind detectors, rather than using pilot symbols that results in a bandwidth loss, we propose novel totally blind decoders using dual constellations or a superimposed training scheme. To alleviate the computational burden, a minimum mean-squareerror (MMSE) channel estimator is also proposed to track the time-varying channel without using the blind decoder.

A Hadamard matrix of side n is an n × n matrix with every entry either 1 or −1, which satisfies HH T = nI. Two Hadamard matrices are called equivalent if one can be obtained from the other by some sequence of row and column permutations and negations. To identify the equivalence of two Hadamard matrices by a complete search is known to be an NP hard problem when n increases. In this paper, a new algorithm for detecting inequivalence of two Hadamard matrices is proposed, which is more sensitive than those known in the literature and which has a close relation with several measures of uniformity. As an application, we apply the new algorithm to verify the inequivalence of the known 60 inequivalent Hadamard matrices of order 24; furthermore, we show that there are at least 382 pairwise inequivalent Hadamard matrices of order 36. The latter is a new discovery.

Many construction methods for (nearly) uniform designs have been proposed under the centered L 2-discrepancy, and most of them are only suitable for constructing designs with small size. This paper proposes a new method, called mixture method (MM), to construct nearly symmetrical/asymmetrical uniform designs with large number of runs and/or large number of factors. The new method has the "better than given" property, i.e., the resulting design is better than existing designs in the sense of the pre-decided criterion. Moreover, the computational speed of MM is faster than most existing methods.

Experimental designs are very important in chemometrics, since chemistry, until now, is still essentially a field of science strongly dependent on chemical experiments. So, for a long time, chemists have been trying to use the techniques of experimental design developed in statistics to improve experimental works. Three major methods of experimental design, such as Ž. Ž. factorial design including fractional factorial design and orthogonal design OD , D-optimal design and uniform design UD , and their applications in chemistry and chemical engineering are reviewed and compared. The features of uniform design are especially addressed. Uniformity of space filling is the most important and essential feature of the uniform design. Based on this feature, its cost-efficiency, robustness and flexibility make it very useful in the fields of chemistry and chemical engineering. Examples of successful applications of uniform design on improving technologies of various fields such as textile industry, pharmaceuticals, fermentation industry and others have been consistently reported in China since the 1980s. More recently, several various cases applying uniform design to chemical researches showed that the uniform design is indeed a very promising and powerful experimental design method.

The common methods used by chemists to obtain the estimates of the kinetic rate constants are deterministic ones. The Ž. statistical methods, such as D-optimum design DOD , can offer a better way to deal with this problem. But the kinetic model of a reversible reaction is nonlinear, the DOD is locally optimal at the value of the initial chosen parameters. The goal of this Ž. Ž. article is to try to put different experimental design techniques, i.e., uniform design UD , orthogonal design OD and DOD into a common framework, and to attempt to gain some insight on when, where and which of these three experimental methods can be expected to work well. The extensive Monte Carlo experiments have been done in order to compare the performances of these methods. The results show that the DOD often gives the best performance, but it is easy to break down in estimation of parameters, when the initial parameters are far away from the true parameters. The OD also breaks down in some situations. The UD is the most stable, and it works well in all situations.

The common methods used by chemists to obtain the estimates of the kinetic rate constants are deterministic ones. The Ž. statistical methods, such as D-optimum design DOD , can offer a better way to deal with this problem. But the kinetic model of a reversible reaction is nonlinear, the DOD is locally optimal at the value of the initial chosen parameters. The goal of this Ž. Ž. article is to try to put different experimental design techniques, i.e., uniform design UD , orthogonal design OD and DOD into a common framework, and to attempt to gain some insight on when, where and which of these three experimental methods can be expected to work well. The extensive Monte Carlo experiments have been done in order to compare the performances of these methods. The results show that the DOD often gives the best performance, but it is easy to break down in estimation of parameters, when the initial parameters are far away from the true parameters. The OD also breaks down in some situations. The UD is the most stable, and it works well in all situations.

Experimental designs are very important in chemometrics, since chemistry, until now, is still essentially a field of science strongly dependent on chemical experiments. So, for a long time, chemists have been trying to use the techniques of experimental design developed in statistics to improve experimental works. Three major methods of experimental design, such as Ž. Ž. factorial design including fractional factorial design and orthogonal design OD , D-optimal design and uniform design UD , and their applications in chemistry and chemical engineering are reviewed and compared. The features of uniform design are especially addressed. Uniformity of space filling is the most important and essential feature of the uniform design. Based on this feature, its cost-efficiency, robustness and flexibility make it very useful in the fields of chemistry and chemical engineering. Examples of successful applications of uniform design on improving technologies of various fields such as textile industry, pharmaceuticals, fermentation industry and others have been consistently reported in China since the 1980s. More recently, several various cases applying uniform design to chemical researches showed that the uniform design is indeed a very promising and powerful experimental design method.

Conjoint analysis studies involving many attributes and attribute levels often occur in practice. Because such studies can cause respondent fatigue and lack of cooperation, it is important to design data collection tasks that reduce those problems. Bridging designs, incorporating two or more task subsets with overlapping attributes, can presumably lower task difficulty in such cases. In this paper, we present results of a study examining the effects on predictive validity of bridging design decisions involving important or unimportant attributes as links (bridges) between card-sort tasks and the degree of balance and consistency in estimated attribute importance across tasks. We also propose a new symmetric procedure, Symbridge, to scale the bridged conjoint solutions.

The wrist force/torque sensors has been increasinly used in variety of robotic fields which the most important one is human-computer interactions. Applied features of the force/torque sensors have motivated scientists to investigate novel techniques with regard to save machining costs and time before fabricating them. This paper represents the effect of fillet as a practical manufacturing method to decrease the costs and time and icrease the resolution of a four axis force/torque sensor, simultaneously. In adition, a kind of face machining technique is performed to aim the proposed goals. Using finite element analysis by commercial finite element software, ABAQUS, is then implemented to validate the proposed model. The results proof the efficiency of the methods. Keywords—force and torque sensor; human-computer interaction, cross-beams; fillet; finite element analysis

Plastic materials are used in automobile, electrical and electronic applications, agricultural utilization, household and furniture products, and medical equipments. Among various plastic manufacturing process, injection molding is one of the most commonly used and common methods applied for forming plastic products in the industry. The process requires a molten polymer being injected into a cavity of a mold, which is cooled and the product ejected from the mold. During the Plastic Injection Molding (PIM) process, various defects, such as volumetric shrinkage, warpage, weld line and sink mark can occur. This paper presents a method to minimizing warpage defect on PolyPropylene AZ564 via PIM simulation using Moldflow software. The approach was based on Taguchi method. Through the effectiveness of this proposed method, it is confirmed using simulation by Moldflow software. The effect of the process parameters on the warpage of a motorcycle number plate bracket, is studied using analysis of variance (ANOVA). From the ANOVA, the significant parameters affecting the process are holding time, holding pressure and injection pressure. The result of the Taguchi prediction shown that minimum warpage is 1.078 mm, which is 7.14% and 9.09% different from the simulation result and experiment, respectively.

Plastic materials are used in automobile, electrical and electronic applications, agricultural utilization, household and furniture products, and medical equipments. Among various plastic manufacturing process, injection molding is one of the most commonly used and common methods applied for forming plastic products in the industry. The process requires a molten polymer being injected into a cavity of a mold, which is cooled and the product ejected from the mold. During the Plastic Injection Molding (PIM) process, various defects, such as volumetric shrinkage, warpage, weld line and sink mark can occur. This paper presents a method to minimizing warpage defect on PolyPropylene AZ564 via PIM simulation using Moldflow software. The approach was based on Taguchi method. Through the effectiveness of this proposed method, it is confirmed using simulation by Moldflow software. The effect of the process parameters on the warpage of a motorcycle number plate bracket, is studied using analysis of variance (ANOVA). From the ANOVA, the significant parameters affecting the process are holding time, holding pressure and injection pressure. The result of the Taguchi prediction shown that minimum warpage is 1.078 mm, which is 7.14% and 9.09% different from the simulation result and experiment, respectively.

Data shuffling is one of the fundamental building blocks for distributed learning algorithms, that increases the statistical gain for each step of the learning process. In each iteration, different shuffled data points are assigned by a central node to a distributed set of workers to perform local computations, which leads to communication bottlenecks. The focus of this paper is on formalizing and understanding the fundamental information-theoretic tradeoff between storage (per worker) and the worst-case communication overhead for the data shuffling problem. We completely characterize the information theoretic tradeoff for K = 2, and K = 3 workers, for any value of storage capacity, and show that increasing the storage across workers can reduce the communication overhead by leveraging coding. We propose a novel and systematic data delivery and storage update strategy for each data shuffle iteration, which preserves the structural properties of the storage across the workers, and aids in minimizing the communication overhead in subsequent data shuffling iterations. Related Work: In the past few years, there has been a flurry of research acitivity in understanding the benefits of coding for caching starting from the work of Maddah-Ali and Niesen [6] who showed that exploiting multi-casting opportunities by coding can reduce the communication for caching. In [7], coding for MapReduce was proposed in order to reduce the communication cost between mappers and reducers, however the underlying focus of [7] is significantly different than the problem considered in this work, where we care about the communication between the master node and the workers. The paper most closely related to this work is [8], where the idea of coding for data shuffling problem is presented to reduce the communication overhead between the master node and worker nodes. [8] provides a probabilistic scheme of leveraging coding based on a random storage placement. In contrast to [8], in this paper we provide a deterministic and systematic storage update scheme, which increases the coding opportunities in the delivery phase. The underlying metric used here is the worstcase communication cost over all the possible shuffles, unlike the average cost considered in [8]. Finally, we also present the first information theoretic lower bounds on the communication overhead for the data shuffling problem.

Conjoint Analysis (CA) is a very popular class of methods for measuring consumer preferences, both in research and practice. However, since a couple of years, the Analytic Hierarchy Process (AHP) is being discussed in this field as well. Several empirical studies have shown the general potential of AHP, particularly in complex product evaluation tasks consisting of many attributes. But, in spite of its promising results, marketing practice seems to ignore AHP so far. This is somewhat astonishing if one considers the closeness of both approaches. Already almost thirty years ago Wind and Saaty (1980, p. 657) stated: "In some cases both the AHP and Conjoint Analysis can be used, and it is desirable to compare the results of the two approaches …". This paper contributes to fill this gap. In order to increase the practical relevance of such a comparison for marketing practitioners, we run AHP against the commercially successful Choice-Based Conjoint Analysis (CBC) in an online survey. We outline how both the hierarchy and the scale used in AHP can be adapted to preference measurement and how Harker's (1987) technique for incomplete pairwise comparison matrices can be applied in a beneficial way. Our results indicate that, indeed, both methods are equivalent with regard to convergent validity and the individual prediction of holdout tasks, but AHP significantly outperforms CBC in market share predictions.

In this paper, we propose a generalized code index modulation (CIM) technique for direct sequence-spread spectrum (DS-SS) communication. In particular, at the transmitter, the bit stream is divided into blocks in which each block is divided into two sub-blocks, named as mapped and modulated sub-block. Thereafter, the bits within the mapped sub-block are used to select one of the predefined spreading codes, which is then used to spread the modulated bits of the second sub-block. In this design, the use of the spreading code index as an information-bearing unit increases the overall spectral efficiency of this system. At the receiver side, the spreading code index is first estimated, thus resulting in a direct estimation of mapped sub-block bits. Consequently, the corresponding spreading code to this estimated index is used to de-spread the modulated symbol of the modulated sub-block. Subsequently, mathematical expressions for bit error rate, symbol error rate, throughput, energy efficiency, and the system complexity are derived to analyze the system performance. Finally, simulation results show that the proposed modulation scheme can achieve higher data rate than the conventional DS-SS system, with lower energy consumption and complexity.

Page 1. Uniform Design: Theory and Application Kai-Tai FANG ... h(xl,...,x,) can be expressed as : iki(2l : s), optimal design theory can provide the most efficient de-sign. If Model (1.3) cannot be expressed as (1.2), an ap-proximately linear regression model may be considered: ...

Theory development is a very complex process that requires creativity and highly specialized analytical skills. This article presents a new algorithm, based on causal mapping, for assisting in the creation of qualitative theories. This algorithm is able to conjecture and prove new theorems, to test for consistency and completeness of the theory, and to derive meta-theorems comparing the different concepts in it. The use of the algorithm is exemplified in developing a theory to explain structural inertia in organizations.

Space-time block codes based on orthogonal designs (ODs) are used for wireless communications with multiple transmit antennas which can achieve full transmit diversity along single-symbol maximum-likelihood decodability. Single-Symbol Decodable (SSD) codes which are not ODs can be constructed having slightly higher rate than ODs. Elegant constructions of SSD codes using Clifford algebras (Karmakar and Rajan, proceedings of IEEE ISIT, 2006) are known. But these codes, for transmitting antennas more than 4, have large number of zeros in it. Due to the zero entries in the design, the transmitting antenna need to be switched on and off imposing severe hardware constraints. This motivates the construction of SSD codes having no zero entries in the codeword matrices. In this paper we propose a technique for constructing SSD codes having no zero entries in it, having larger rate than the known constructions of the same.

The purpose of this paper is to model the desires, expectations and priorities of the inhabitants of Istanbul, a city with a population of about 15 million, from a multidimensional perspective. In this way, effective allocation of the city's resources can be achieved to improve the quality of life for such a large number of people, which is the primary concern of the local authorities as well as the urban planners. A survey is conducted in Istanbul so that the priorities of the inhabitants are revealed and the city where they would like to live is portrayed. The data obtained are used as input for hierarchical conjoint analysis, a decompositional multivariate data analysis technique frequently used in marketing. The survey is primarily based on the evaluation of hypothetical, orthogonally-designed city profiles for four different constructs and a bridging construct on a 0-10 rating scale. The relative importances of the constucts and their attributes are estimated at both the individual and the aggregate level. A segmentation is made based on the demographic and social characteristics of the respondents to reflect different classes. The research is an interdisciplinary group work acting as a bridge between urban planning and multiattribute decision making, thus judgments of experts from different disciplines are used in every stage of the study. 1 38 th CONGRESS OF THE EUROPEAN REGIONAL SCIENCE ASSOCIATION URBAN QUALITY OF LIFE IN ISTANBUL : PRIORITIES AND SEGMENTATION %XUo h/(1*ø1 hPLW *h9(1d )VXQ h/(1*ø1

The performance of space-time block codes for transmission over Quasi-static Rayleigh flat fading channels using multiple transmit antennas is considered. Data is prearranged using a space-time block code, which is split in to parallel streams via simultaneously transmitted transmit antennas. The received signal at each receive antenna is a linear superposition of the n transmitted signals perturbed by noise. Maximum likelihood decoding is carried out by dividing the signals transmitted from different antennas. This uses the orthogonal structure of the space-time block code and gives a maximum-likelihood decoding algorithm, which is based only on linear processing at the receiver. The performance of Space Time Block Codes for 1 bit/sec/HZ and 2 bits/sec/HZ using BPSK,QPSK Modulation Schemes for four and eight transmit antennas with code rate of 1/2 and 4/7 is evaluated. By increasing the code rate of the system using four transmit antennas, significant gains are achieved compared to existing system.

The present paper discusses the selection of process parameters for obtaining optimal magnetic properties in strontium ferrite sintered magnets. The magnetic properties have several quality characteristics, such as remanence, coercivity and energy product, etc. To consider these quality characteristics in the selection of process parameters, the Taguchi L9 design is adopted. Experimental results are provided to illustrate the proposed approach.

From time immemorial, human beings have used pigments made from vegetables, fruits, superior plants, animal tissues and cereals. One of the greatest sources of pigments is the bacterium that, with the use of the modern technology, has increased the production of metabolites of interest. The microbiological production of carotenoids has not been optimized to obtain pigment production quantities of pigments and carotenoids recovery that lower production costs. The aim of this work was to design a Zeaxanthin production process with Flavobacterium sp. immobilized cells in a fluidized bed bioreactor. An optimum culture medium for Zeaxanthin production in stirred flasks (2.46 g•L-1) was obtained. Furthermore, optimum process conditions for a maximum yield of Zeaxanthin production, by fluidized bed bioreactor, were established. A statistical analysis showed that the most significant factors were air flow, pH and NaCl concentration (4.5 g•L-1). In this study a maximum Zeaxanthin production of 3.8 g•L-1 was reached. The highest reported yield to date was 0.329 g•L-1 .

The consumer market has changed drastically in recent times. Consumers are becoming more demanding, and many companies are competing to be market leaders. Therefore, companies must reduce rejects and minimize their operating costs. One problem that arises in producing plastic parts is controlling deformation, mainly in the form of shrinkage due to the material and warpage associated with the geometry of the parts. This work presents a novel extended adaptive weighted sum method (EAAWSM: Extended Adaptive Weighted Summation Method) integrated into a Pareto front model. The performance of this model is evaluated against three other conventional optimization methods—Taguchi–Gray (TG), Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), and Model Optimization by Genetic Algorithm (MOGA)—and compared with EAAWSM. Two response variables and three input factors are considered to be analyzed: material melting temperature, mold temperature, and filling time. Subsequen...

Orthogonal designs and their special cases such as weighing matrices and Hadamard matrices have many applications in combinatorics, statistics, and coding theory as well as in signal processing. In this paper we generalize the definition of orthogonal designs, we give many constructions for these designs and we prove some multiplication theorems that, most of them, can also be applied in the special case of orthogonal designs. Some necessary conditions for the existence of generalized orthogonal designs are also given.

The present work deals with surface roughness characteristics of electroless Ni-P coatings. The optimised process parameters have been determined based on L27 Taguchi Orthogonal array. Bath concentration of nickel sulphate, concentration of sodium hypophosphite and temperature of bath has been considered as variable in this study. The optimum combinations of process parameters and surface roughness have been considered as response variable of the study. It has been found that 24 g/L of Nickel Sulfate, 25 g/L of Sodium Hypophosphite and 80°C temperature gives the minimum surface roughness of the Ni-P coated sample which was 0.23µm. Characterisation of the substrate and the as deposited samples were done by scanning electron microscope (SEM) and optical microscopy for surface morphology, energy-dispersive X- ray analysis (EDAX) for element analysis and X-ray diffraction for phase analysis.

It is shown that the complement of a universally optimal design derivable from a triangular design is again universally optimal in a class of connected designs. Furthermore, some series of universally optimal designs for diallel cross experiments are provided. These observations strengthen the result on universally optimal designs by Das, Dey and Dean (1998).

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