Complex Constellations Research Articles

Training-Symbol Embedded, High-Rate, Single-Symbol ML-Decodable, Distributed STBCs for Relay Networks

Distributed space-time block codes (DSTBCs) from complex orthogonal designs (CODs) (both square and nonsquare), coordinate interleaved orthogonal designs (CIODs), and Clifford unitary weight designs (CUWDs) are known to lose their single-symbol ML decodable (SSD) property when used in two-hop wireless relay networks using amplify and forward protocol. For such networks, in this paper, three new classes of high rate, training-symbol embedded (TSE) SSD DSTBCs are constructed: TSE-CODs, TSE-CIODs, and TSE-CUWDs. The proposed codes include the training symbols inside the structure of the code which is shown to be the key point to obtain the SSD property along with the channel estimation capability. TSE-CODs are shown to offer full-diversity for arbitrary complex constellations and the constellations for which TSE-CIODs and TSE-CUWDs offer full-diversity are characterized. It is shown that DSTBCs from nonsquare TSE-CODs provide better rates (in symbols per channel use) when compared to the known SSD DSTBCs for relay networks. Important from the practical point of view, the proposed DSTBCs do not contain any zeros in their codewords and as a result, antennas of the relay nodes do not undergo a sequence of switch on/off transitions within every codeword, and, thus, avoid the antenna switching problem.

Finanzierung und finanzielle Probleme von Leistungen und Strukturen im Fachgebiet Gynäkologie und Geburtshilfe im Jahr 2011 – DRG-System und stationäre Versorgung inklusive Urogynäkologie und benigner wie auch maligner gynäkologischer Operationen

The public discussion about health care financing has an enormous relevance for the field of gynaecology and obstetrics. This second part of the paper of the financing commission of the DGGG presents essential financial aspects and problems, influencing our speciality. Among other aspects, the inputs of the DRG system are discussed for our field. The representation of all levels of care and all German states in the InEK calculation system is still a problem. Regarding the inpatient care, the number of cases has decreased by 23 over the last years due to the shift to the outpatient setting. Surgeries in the outpatient setting have increased by 31.5 from the year 2004 to the year 2008 (all specialities). Moreover, a decrease of obstetric cases by 5.7 and cases directly associated with birth by 7.3 has to be mentioned. Altogether, our field has lost 6.8 of all inpatient cases over the last years. The economic pressure is still high and it is difficult to maintain cost recovery. Regarding the personal resources, legal demands are problematic for perinatal centres, e. g. loss of the on-call duty possibility, availability of medical specialist expertise and necessity of permanent standby service of the head of the perinatal centre. Further problems of the inpatient setting concern the field of urogynaecology (lack of young academics, new technical procedures with lack of data, missing representation of complex surgeries and lack of reimbursement in case of surgeries in the outpatient setting) and the benign and malign gynaecological surgery. While standard procedures are almost represented in the DRG system, there is still a high demand for development of appropriate reimbursement for complex and infrequent case constellations, interdisciplinary procedures and simultaneous multiplex surgeries. The collaboration of all colleagues is essential.

Prototype personality diagnosis in clinical practice: A viable alternative for DSM–5 and ICD–11.

Several studies suggest that a prototype matching approach yields diagnoses of comparable validity to the more complex diagnostic algorithms outlined in DSM-IV. Furthermore, clinicians prefer prototype diagnosis of personality disorders (PDs) to the current categorical diagnostic system or alternative dimensional methods. An important extension of this work is to investigate the degree to which clinicians are able to make prototype diagnoses reliably. The aim of this study is to assess the inter-rater reliability of a prototype matching approach to personality diagnosis in clinical practice. Using prototypes derived empirically in prior research, outpatient clinicians diagnosed patients' personality after an initial evaluation period. External evaluators independently diagnosed the same patients after watching videotapes of the same clinical hours. Inter-rater reliability for prototype diagnosis was high, with a median r = .72. Cross-correlations between disorders were low, with a median r = .01. Clinicians and clinically trained independent observers can assess complex personality constellations with high reliability using a simple prototype matching procedure, even with prototypes that are relatively unfamiliar to them. In light of its demonstrated reliability, efficiency, and versatility, prototype diagnosis appears to be a viable system for DSM-V and ICD-11 with exceptional utility for research and clinical practice.

Efficiently decoded full-rate space-time block codes

Space-time block codes with orthogonal structures typically provide full-diversity reception and simple receiver processing. However, rate-1 orthogonal codes for complex constellations have not been found for more than two transmit antennas. By using a genetic algorithm, rate-1 space-time block codes that accommodate very simple receiver processing at the cost of reduced diversity are designed in this paper for more than two transmit antennas. Simulation results show that evolved codes combined with efficient outer codes provide better performance over fading channels than minimum-decoding-complexity quasiorthogonal codes at typical operating signal-to-noise ratios. When the fading is more severe than Rayleigh fading, the spectral efficiency is specified, and an efficient outer code is used, evolved codes outperform orthogonal space-time block codes.

Low PAPR square STBCs from complex partial-orthogonal designs (CPODs)

Space-time codes from complex orthogonal designs (CODs) with no zero entries offer low Peak to Average Power Ratio (PAPR) and avoid the problem of switching off antennas. But square CODs for 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sup> antennas with a+1 complex variables, with no zero entries were discovered only for a ⩽ 3 and if a+1 = 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">k</sup> , for k ⩾ 4. In this paper, a method of obtaining no zero entry (NZE) square designs, called Complex Partial-Orthogonal Designs (CPODs), for 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a+1</sup> antennas whenever a certain type of NZE code exists for 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a</sup> antennas is presented. Then, starting from a so constructed NZE CPOD for n = 2 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">a+1</sup> antennas, a construction procedure is given to obtain NZE CPODs for 2n antennas, successively. Compared to the CODs, CPODs have slightly more ML decoding complexity for rectangular QAM constellations and the same ML decoding complexity for other complex constellations. Using the recently constructed NZE CODs for 8 antennas our method leads to NZE CPODs for 16 antennas. The class of CPODs do not offer full-diversity for all complex constellations. For the NZE CPODs presented in the paper, conditions on the signal sets which will guarantee fulldiversity are identified. Simulation results show that bit error performance of our codes is same as that of the CODs under average power constraint and superior to CODs under peak power constraint.

Generalized Equalization Algorithm Utilizing Improper ISI

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The improper nature of intersymbol interference (ISI) for signals transmitted over frequency-selective channels is investigated in this paper. Our analysis reveals that for real signals, the improperness originates from both improper signal modulation and the interference cancellation process, whereas for most complex signals, the improperness is only a characteristic of the residual ISI due to interference cancellation. To utilize the improperness of ISI, a multistage widely linear equalization algorithm is introduced, and it is generally applicable for both real and complex signal constellations. The results reveal that accounting for the improper nature of the ISI at both the input and output of the equalizer leads to a noticeable performance gain compared with conventional equalization schemes. </para>

“GenderPlex” a PCR multiplex for reliable gender determination of degraded human DNA samples and complex gender constellations

The amelogenin test integrated in most commercial polymerase chain reaction (PCR) multiplex kits is routinely used in the forensic field for gender determination of DNA samples. It has been demonstrated that this test is not entirely reliable. Males with deletions in the homologous amelogenin part on the Y chromosome (AMELY) were erroneously typed as females due to lack of Y-specific amelogenin amplification. Also, primer binding site mutations that result in a failure to amplify the AMELY or the X-chromosomal part (AMELX) have been observed. For clarification of such phenomena, a new PCR multiplex (GenderPlex) is presented, co-amplifying two different regions of the amelogenin gene (55/58 and 106/112 bp for the AMELX and AMELY alleles, respectively), a 93-bp sequence stretch of the SRY gene and four mini-X-STR loci DXS7424, DXS8378, DXS6803 and GATA172D05 (maximum product size less than 140 bp). This strategy helps with the evaluation of samples for the presence of amelogenin-based primer site mutations and confirms a male genotype by the absence of heterozygote X-STR alleles and the presence of an SRY-related peak. The short amplicon sizes of all involved loci proved to be beneficial in a study on artificially degraded DNA. Furthermore, we demonstrate by means of sensitivity, human specificity and mixture studies that the multiplex is suitable for investigations in the forensic scene. Finally, the performance of the GenderPlex was evaluated on a west Eurasian population sample from Austria comprising 166 male and 104 female individuals.

Language and Music: What do they have in Common and how do they Differ? A Neuroscientific Approach

The concept of two largely independent systems, with strict left hemisphere lateralization of language and predominantly right lateralization of music is being challenged by the alternative view that language and music are closely related cognitive and neural systems with complex constellations of sub-processes, some of which are shared, and others that are not. Neurophysiologic data demonstrating similar syntax and semantics processing together with similarities in the development of the two domains in the infant brain support that language and music have much in common and complement each other. Close interaction between the two hemispheres is needed for optimal functioning of both language and music. Thus, the right hemisphere has an important role for understanding complex natural language such as stories and metaphors. Learning to read, write and musical training induces functional and anatomical changes in functionally relevant connections, and modifies hemispheric asymmetries for specific functions. Comparative research on music and language provides a way to study basic brain mechanisms and how the brain transfers acoustic stimuli into the unique human abilities for language and music, and may help bridge the divide between the sciences and the humanities.

High-rate Complex Orthogonal Space-time Block Codes for 5 and 6 Transmit Antennas

Based on orthogonal designs, space-time (ST) block codes that enable full diversity as well as a simple maximum likelihood (ML) decoding algorithm at the decoder can be constructed for more than two transmit antennas. For real constellations (such as PAM), ST block codes with transmission rate 1 can be designed from the real Hurwitz-Radon families for any number of transmit antennas. However, for complex constellations (such as M-PSK or M-QAM), ST block codes for more than two transmit antennas can only be constructed with rates less than 1. Previous attempts have been concentrated on complex orthogonal designs that provide ST block codes with full diversity and high transmission rates. In this paper, we present two rate 2/3 complex ST block codes from orthogonal designs for five and six transmit antennas, respectively. Simulation results are provided to demonstrate the significant performance gains made by the proposed ST block codes.

Optimal Throughput-Diversity-Delay Tradeoff in MIMO ARQ Block-Fading Channels

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, we consider an automatic-repeat-request (ARQ) retransmission protocol signaling over a block-fading multiple-input–multiple-output (MIMO) channel. Unlike previous work, we allow for multiple fading blocks within each transmission (ARQ round), and we constrain the transmitter to fixed rate codes constructed over complex signal constellations. In particular, we examine the general case of average input-power-constrained constellations with a fixed signaling alphabet of finite cardinality. This scenario is a suitable model for practical wireless communications systems employing orthogonal frequency division multiplexing (OFDM) techniques over a MIMO ARQ channel. Two cases of fading dynamics are considered, namely, short-term static fading where channel fading gains change randomly for each ARQ round, and long-term static fading where channel fading gains remain constant over all ARQ rounds pertaining to a given message. As our main result, we prove that for the block-fading MIMO ARQ channel with a fixed signaling alphabet satisfying a short-term power constraint, the optimal signal-to-noise ratio (SNR) exponent is given by a modified Singleton bound, relating all the system parameters. To demonstrate the practical significance of the theoretical analysis, we present numerical results showing that practical Singleton-bound-achieving maximum distance separable codes achieve the optimal SNR exponent. </para>

Assessment of Cross-Reactivity between Mycobacterium bovis and M. kansasii ESAT-6 and CFP-10 at the T-Cell Epitope Level

Cross-reactivity between Mycobacterium kansasii ESAT-6 and CFP-10 homologues and their M. bovis counterparts can confound the interpretation of immunodiagnostic tests for tuberculosis. M. kansasii is a nontuberculous mycobacterial species cultured from skin test-positive cattle in Great Britain. Using peptides derived from M. bovis and M. kansasii ESAT-6 and CFP-10 regions that differ between these species, we investigated the species specificity and cross-reactivity at the level of individual bovine T-cell epitopes. Our results demonstrated that all peptides tested are fully cross-reactive, with the exception of one ESAT-6-derived peptide that harbored an M. bovis-specific epitope(s) when it was recognized in the context of bovine leukocyte antigen (BoLA)-DQ but that was cross-reactive with its M. kansasii homologues when it was restricted by BoLA-DR. This observation further highlights that prediction of species specificity by comparing sequence identity/homology alone is not sufficient and that individuals with diverse major histocompatibility complex constellations need to be tested to characterize the cross-reactivity or species specificity of peptide-based reagents.

The short-term treatment of narcissistic and other self-disorders

The term narcissism when used clinically, is broad and its boundaries are diffused. Freud first referred to narcissism to describe a libidinal position in which cathexes were invested in the subject's own ego and not in objects. Dynamically, significant advances have been made in the clarification of the methapsychological dimensions of narcissistic disorders. Two authors, Otto Kernberg (1984, 1986, 1998) and Heinz Kohut (1971, 1977), have advanced well-developed metapsychologies for these disorders and proposed comprehensive techniques for their treatment through appropriately modified psychoanalytically based interventions. In both cases, treatment is deemed to be plagued by problems, to last long, and to result in uncertain outcomes. The metapsychological clarity achieved by authors such as Kohut and Kernberg has so far not generated a proportionate therapeutic optimism.In this paper, a review will be presented of the current status of the outcome of the treatment, through short-term dynamic psychotherapy, of a spectrum of psychoneurotic disorders, with special emphasis on the treatment of patients suffering from syndromes that reflect complex dynamic constellations resulting from the interaction of impulse problems and problems of object loss at key developmental moments, which affect the patient's relationships with developmentally key objects. Also presented will be techniques derived from this framework for the treatment of patients suffering from a range of narcissistic disorders, including Narcissistic Personality Disorder, as well as innovative techniques designed by the author to meet the unique treatment needs of self-disordered patients in shorter time frames than are common in the classically open-ended psychodynamic technique.

Fast and low complexity blind equalization via subgradient projections

We propose a novel blind equalization method based on subgradient search over a convex cost surface. This is an alternative to the existing iterative blind equalization approaches such as the Constant Modulus Algorithm (CMA), which often suffer from the convergence problems caused by their nonconvex cost functions. The proposed method is an iterative algorithm called SubGradient based Blind Algorithm (SGBA) for both real and complex constellations, with a very simple update rule. It is based on the minimization of the l/sub /spl infin// norm of the equalizer output under a linear constraint on the equalizer coefficients using subgradient iterations. The algorithm has a nice convergence behavior attributed to the convex l/sub /spl infin// cost surface as well as the step size selection rules associated with the subgradient search. We illustrate the performance of the algorithm using examples with both complex and real constellations, where we show that the proposed algorithm's convergence is less sensitive to initial point selection, and a fast convergence behavior can be achieved with a judicious selection of step sizes. Furthermore, the amount of data required for the training of the equalizer is significantly lower than most of the existing schemes.

Cardiovascular risk factors in primary care: methods and baseline prevalence rates – the DETECT program

ABSTRACTObjectives: DETECT is an epidemiological study in primary care to examine (a) the prevalence rates and comorbidity of diabetes mellitus, hypertension, hyperlipidaemia and coronary heart disease (CHD), and associated conditions; (b) the frequency of behavioural and clinical risk factors for onset and progression; (c) the 12-month course and outcome; and (d) the met and unmet needs for these patients.Methods: Three-stage, cross-sectional clinical-epidemiological study with a prospective-longitudinal component in a nationally representative sample of N = 3795 primary care settings [response rate (RR): 60.2%] and N = 55 518 patients (RR: 95.5%). Patients completed a standardized assessment, including questionnaires for patients and the physician and diagnostic screening measures (i.e. blood pressure, heart rate, body mass index and waist circumference assessments). A subsample of patients (N = 7519) also completed a standardized laboratory screening program and was followed-up after 12 months. Data were weighted to adjust for non-response, regional distribution and attrition.Results: (1) Doctors and patients sample can be regarded as representative for primary care settings in Germany. (2) The clinician-rated point prevalence of hypertension is highest (35.5%), followed by hyperlipidaemia (29.1%), diabetes (14.1%) and CHD (12.1%); prevalence rates of each disorder as well as their co-incidence rates increase markedly with age. (3) The vast majority (78%) of all patients revealed multiple (3+) behavioural and clinical risk factors.Conclusion: The findings of DETECT underline the considerable burden for primary care doctors in managing a highly morbid patient population, with predominantly complex risk factor constellations, in routine care. Our data provide, in unprecedented detail, a basis for calculating age-, gender- and risk-group-adjusted risk-factor profiles in routine care.

Algebraic identification for optimal nonorthogonality 4/spl times/4 complex space-time block codes using tensor product on quaternions

The design potential of using quaternionic numbers to identify a 4/spl times/4 real orthogonal space-time block code has been exploited in various communication articles. Although it has been shown that orthogonal codes in full-rate exist only for 2 Tx-antennas in complex constellations, a series of complex quasi-orthogonal codes for 4 Tx-antennas is still proposed to have good performance recently. This quasi-orthogonal scheme enables the codes to reach the optimal nonorthogonality, which can be measured by taking the expectation over all transmit signals of the ratios between the powers of the off-diagonal and diagonal components. This correspondence extends the quaternionic identification to the above encoding methods. Based upon tensor product for giving the quaternionic space a linear extension, a complete necessary and sufficient condition for identifying any given complex quasi-orthogonal code with the extended space is generalized by considering every possible two-dimensional R-algebra.

Layered space-time multiuser detection over wireless uplink systems

In this paper, we investigate the use of layered space-time (also known as the vertical Bell Laboratories layered space-time (V-BLAST) scheme) for multiuser detection in fading channels. The multiple transmit antennas in V-BLAST are treated as individual mobile station transmitters, while the base station consists of multiple receive antennas. In the proposed system, users are organized in groups and allocated a unique spreading code within the same group. Using these codes, we are able to separate the different groups, and layered space-time algorithm is then invoked to further remove the remaining interference between users. A decorrelator-type receiver-based layered space-time detection is proposed for both complex and real constellations. For the latter case, we derive our receiver after evaluating and comparing the performance of two decorrelators based on the V-BLAST scheme. It is demonstrated that a significant performance improvement and increase in system capacity is obtained with very low spreading factors. Further results are also introduced by considering reduced complexity receivers based on serial layered space-time group multiuser detection, and parallel layered space-time group multiuser detection.

On Space-Time Block Codes from Complex Orthogonal Designs

Space-time block codes from orthogonal designs recently proposed by Alamouti, and Tarokh-Jafarkhani-Calderbank have attracted considerable attention due to the fast maximum-likelihood (ML) decoding and the full diversity. There are two classes of space-time block codes from orthogonal designs. One class consists of those from real orthogonal designs for real signal constellations which have been well developed in the mathematics literature. The other class consists of those from complex orthogonal designs for complex constellations for high data rates, which are not well developed as the real orthogonal designs. Since orthogonal designs can be traced back to decades, if not centuries, ago and have recently invoked considerable interests in multi-antenna wireless communications, one of the goals of this paper is to provide a tutorial on both historical and most recent results on complex orthogonal designs. For space-time block codes from both real and (generalized) complex orthogonal designs (GCODs) with or without linear processing, Tarokh, Jafarkhani and Calderbank showed that their rates cannot be greater than 1. While the maximum rate 1 can be reached for real orthogonal designs for any number of transmit antennas from the Hurwitz–Radon constructive theory, Liang and Xia recently showed that rate 1 for the GCODs (square or non-square size) with linear processing is not reachable for more than two transmit antennas. For GCODs of square size, the designs with the maximum rates have been known, which are related to the Hurwitz theorem. In this paper, We briefly review these results and give a simple and intuitive interpretation of the realization. For GCODs without linear processing (square or non-square size), we prove that the rates cannot be greater than 3/4 for more than two transmit antennas.

Diagonal algebraic space-time block codes

We construct a new family of linear space-time (ST) block codes by the combination of rotated constellations and the Hadamard transform, and we prove them to achieve the full transmit diversity over a quasi-static or fast fading channels. The proposed codes transmit at a normalized rate of 1 symbol/s. When the number of transmit antennas n=1, 2, or n is a multiple of four, we spread a rotated version of the information symbol vector by the Hadamard transform and send it over n transmit antennas and n time periods; for other values of n, we construct the codes by sending the components of a rotated version of the information symbol vector over the diagonal of an n /spl times/ n ST code matrix. The codes maintain their rate, diversity, and coding gains for all real and complex constellations carved from the complex integers ring Z [i], and they outperform the codes from orthogonal design when using complex constellations for n > 2. The maximum-likelihood (ML) decoding of the proposed codes can be implemented by the sphere decoder at a moderate complexity. It is shown that using the proposed codes in a multiantenna system yields good performances with high spectral efficiency and moderate decoding complexity.

Optimised Complex Constellations for Transmitter Diversity

In this paper transmitter antenna diversity for the downlink of a cellular system is proposed in conjunction with optimum anti-fading diversity. In spectrally efficient transmitter antenna, frequency and time diversity schemes the information bit stream is divided into sub-streams and each sub-stream is transmitted over a different antenna, a different frequency, or a different time slot. The present work provides a fading resistant transmission scheme where a base station uses M1 antennas and M2 time slots M=M1+M2. These transmissions are coordinated to mitigate the effects of multi-path Rayleigh fading and the mobile receiver can recover the entire M-dimensional transmitted vector as long as the signal energy of at least one coordinate is large enough. The Selective Transmitter Antenna Diversity (space diversity) scheme is coordinated with new Orthonormal Complex Rotation Matrices (time diversity) to get the highest BER performance for low and medium signal to noise ratio. Orthonormal Complex Rotation Matrices with variable and maximum peak to average amplitude ratio (PAR) are presented. The modulations considered in this work are QPSK, 8PSK and 16QAM.

Therapeutic programmes focusing on job related problems - which psychosomatic patients should participate?

The necessity to offer special therapeutic programmes focusing on job related problems in psychosomatic rehabilitation has become increasingly evident. Which patients should participate in such programmes? This question has not yet been discussed with regard to its theoretical and methodological implications. In clinical practice the decision has been based on the therapists evaluation. 105 patients, consecutively admitted in a psychosomatic hospital were interviewed with a screening questionnaire about their job related strains and the perceived interaction between symptomatology and job. According to the literature guidelines for inclusion of psychosomatic patients to a special work hardening programme were used. Therapists were asked to independently assign their patients to the programme. The overlap between the two procedures was small. While the guidelines focussed on a high level of job strain and the patient's motivation for a job-related therapeutic approach, the therapists' decision was based on duration of inability to work, impairments at work due to the symptoms, conflicts with colleagues at work and the patient's ability to perceive problems in a differentiated manner. Considering the problem of inclusion-criteria for a work hardening programme, the highly complex constellations behind routine therapeutic decisions in psychosomatic rehabilitation became evident. To integrate medical diagnosis, symptomatology, psychological models, job strain, the patient's social situation and values, is a neglected but important goal of rehabilitation sciences and should be a base for a concept guiding the development, evaluation and establishment of work related therapeutic programmes.