Unitary Processing Research Articles

The Structure of Speed of Processing Across Cultures.

We examined whether a general processing factor emerges when using response times for cognitive processing tasks and whether such a factor is valid across three different cultural groups (Chinese, Canadian, and Greek). Three hundred twenty university students from Canada (n = 115), China (n = 110), and Cyprus (n = 95) were assessed on an adaptation of the Das-Naglieri Cognitive Assessment System (D-N CAS; Naglieri & Das, 1997). Three alternative models were contrasted: a distinct abilities processing speed model (Model 1) that is dictated by the latent four cognitive factors of planning, attention, simultaneous and successive (PASS) processing, a unitary ability processing speed model (Model 2) that is dictated by the response time nature of all measures, and a bifactor model (Model 3) which included the latent scores of Models 1 and 2 and served as the full model. Results of structural equation modeling showed that (a) the model representing processing speed as a collection of four cognitive processes rather than a unitary processing speed factor was the most parsimonious, and (b) the loadings of the obtained factors were invariant across the three cultural groups. These findings enhance our understanding of the nature of speed of processing across diverse cultures and suggest that even when cognitive processes (i.e., PASS) are operationalized with response time measures, the processing component dominates speed.

Path-Controlled Time Reordering of Paired Photons in a Dressed Three-Level Cascade.

The two-photon dressing of a "three-level ladder" system, here the ground state, the exciton, and the biexciton of a semiconductor quantum dot, leads to new eigenstates and allows one to manipulate the time ordering of the paired photons without unitary postprocessing. We show that, after spectral postselection of the single dressed states, the time ordering of the cascaded photons can be removed or conserved. Our joint experimental and theoretical study demonstrates the high potential of a "ladder" system to be a versatile source of orthogonally polarized, bunched or antibunched pairs of photons.

Analysis of the relation between spectral response and absorptivity of GaAs photocathode

In order to study the relation between spectral response and absorptivity of GaAs photocathode, two kinds of GaAs photocathodes are prepared by molecular beam epitaxy (MBE) and metal-organic chemical vapor deposition (MOCVD), respectively. The samples grown by the MBE include varying doping GaAs photocathodes with different values of emission layer thickness from A to E. The thickness of GaAs emission layer is 1.6 μm or 2 μm. The Al component is 0.5 or 0.63. The samples grown by the MOCVD include varying doping or various component GaAs photocathodes with different values of emission layer thickness and different window layer components from F to J. The thickness values of GaAs emission layer are 1.4 μm, 1.6 μm or 1.8 μm, respectively. The Al component is 0.7 or varies from 0.9 to 0. The doping concentration of the GaAs emission layer is divided into 8 sections between 1×1018 cm-3 and 1×1019 cm-3. The experimental spectral response curves for all samples are obtained by the optical spectrum analyzer. And the experimental reflectivity and transmittivity curves are measured by the ultraviolet visible near infrared spectrohootometer. Based on the law of energy conservation, the absorptivity curves are obtained according to the experimental reflectivity and transmittivity. In the same coordinate system, both the curves are obtained by unitary processing according to the max. A similar surface barrier can be given by dividing the normalized absorptivity by the normalized spectral response, and those are termed the similar I barrier and the similar Ⅱ barrier, respectively. The results indicate that for both the GaAs photocathodes, the experimental spectral response curves both tend to move to the infrared band compared with the experimental absorptivity curves. The average energy differences between absorptivity and spectral response are calculated to be 0.3101 eV for the MBE sample, and 0.3025 eV for the MOCVD sample, respectively. The red-shifts of the photocathodes grown by MBE are a bit bigger than those of the photocathodes grown by MOCVD. In the shortwave region, the absorptivity is very large, but the spectral response cuts off nearby 500 nm. In the visible wavelength region, the peak position of the spectral response curve shifts toward the infrared band for several hundred meV in comparison with the absorptivity curve. In the near infrared region, a red shift of several meV appears at the cut-off position of the spectral response curve in comparison with the absorptivity curve. The results have the guiding significance for improving the photoemission performance of wide-spectrum GaAs photocathode by optimizing the optical performance.

Performance Analysis and Optimization of Distributed Workflows in Heterogeneous Network Environments

Large-scale e-science features complex DAG-structured workflows comprised of computing modules with intricate inter-module dependencies. Mapping such workflows in heterogeneous network environments and optimizing their end-to-end performance are crucial to the success of scientific collaborations that require fast system response and smooth data flow. We construct analytical cost models and formulate workflow mapping as optimization problems for minimum end-to-end delay and maximum frame rate. The difficulty of these problems essentially arises from the topological matching nature in the spatial domain, which is further compounded by the resource sharing complicacy in the temporal dimension. For unitary processing applications, we develop a workflow mapping algorithm based on a recursive critical path optimization procedure to minimize the latency; while for streaming applications, we conduct a rigorous workflow stability analysis and develop a layer-oriented dynamic programming solution based on topological sorting to identify and minimize the global bottleneck time. The accuracy of the proposed exact delay calculation algorithm is verified in comparison with an approximate solution, a dynamic distributed system simulation program, and a real network deployment, and the performance superiority of the proposed mapping approaches are illustrated by extensive simulation-based comparisons with existing algorithms and verified by large-scale experiments on real-life scientific workflows through effective system implementation and deployment in real networks.

Joint Unitary Triangularization for Gaussian Multi-User MIMO Networks

The problem of transmitting a common message to multiple users over the Gaussian multiple-input multiple-output broadcast channel is considered, where each user is equipped with an arbitrary number of antennas. A closed-loop scenario is assumed, for which a practical capacity-approaching scheme is developed. By applying judiciously chosen unitary operations at the transmit and receive nodes, the channel matrices are triangularized so that the resulting matrices have equal diagonals, up to a possible multiplicative scalar factor. This, along with the utilization of successive interference cancellation, reduces the coding and decoding tasks to those of coding and decoding over the single-antenna additive white Gaussian noise channel. Over the resulting effective channel, any off-the-shelf code may be used. For the two-user case, it was recently shown that such joint unitary triangularization is always possible. In this paper, it is shown that for more than two users, it is necessary to carry out the unitary linear processing jointly over multiple channel uses, i.e., space-time processing is employed. It is further shown that exact triangularization, where all resulting diagonals are equal, is still not always possible, and appropriate conditions for the existence of such are established for certain cases. When exact triangularization is not possible, an asymptotic construction is proposed, that achieves the desired property of equal diagonals up to edge effects that can be made arbitrarily small, at the price of processing a sufficiently large number of channel uses together.

Comprehensive Evaluation of Drill Wear Based on the Model of Projection Pursuit

To overcome the deviation caused by the effect of subjective factors in drill wear evaluation, and make the evaluation more accurate and objective, on the basis of drill wear comprehensive evaluation criterion, the projection data are built with projection pursuit method. Two hundred drill wear comprehensive evaluation samples are randomly generated within the range of each class. The projection pursuit model is built by unitary processing according to these samples, which converts the evaluation into non-linear multi-constrained optimization problems. The optimal projection direction vector and the weight coefficient of each evaluation index are obtained with composite simplex method. Meanwhile the corresponding relationship between the region of variation of projection eigenvalue and classification grade is established. The precision of sample evaluation reaches 100% and the evaluation of the measured data achieves good effect. Thus, the scientific evaluation of drill wear is realized by the projection pursuit model.

Visual Context Processing in Schizophrenia

Abnormal perceptual experiences are central to schizophrenia but the nature of these anomalies remains undetermined. We investigated contextual processing abnormalities across a comprehensive set of visual tasks. For perception of luminance, size, contrast, orientation and motion, we quantified the degree to which the surrounding visual context altered a center stimulus' appearance. Across tasks, healthy participants showed robust contextual effects, as evidenced by pronounced misperceptions of center stimuli. Schizophrenia patients exhibited intact contextual modulations of luminance and size, but showed weakened contextual modulations of contrast, performing more accurately than controls. Strong motion and orientation context effects correlated with worse symptoms and social functioning. Importantly, the overall strength of contextual modulation across tasks did not differ between controls and schizophrenia patients. Additionally, performance measures across contextual tasks were uncorrelated, implying discrete underlying processes. These findings reveal that abnormal contextual modulation in schizophrenia is selective, arguing against the proposed unitary contextual processing dysfunction.

Optimal Fixed Gain Linear Processing for Amplify-and-Forward Multichannel Relaying

In this correspondence, we consider the problem of linear processing design at the relay for amplified-and-forward relaying in a multichannel system. Assuming a fixed-gain power amplification at the relay, we study the linear processing structure to maximize the end-to-end achievable rate. For both the cases of relaying with or without direct path, we show that the optimal unitary processing matrix is of permutation structure, i.e., channel pairing is optimal. Furthermore, in each case, the explicit optimal channel pairing strategy is obtained based on sorting certain function of received SNR over the incoming and outgoing subchannels. This result is especially noticeable for the case with direct path, where the optimal linear processing was not known before under any power allocation. Specifically, we show that the pairing is according to the ordering of the relative SNR ratio on a subchannel over first hop to its direct path, and that of SNR strengths on subchannels over the second hop. Simulation results are presented to demonstrate the achievable gain of optimal channel pairing over non-optimal linear processing or no-pairing cases. It is also shown that the performance of channel pairing under the simple fixed-gain power allocation outperforms that under the traditional uniform power allocation.

Using regression to measure holistic face processing reveals a strong link with face recognition ability

Although holistic processing is thought to underlie normal face recognition ability, widely discrepant reports have recently emerged about this link in an individual differences context. Progress in this domain may have been impeded by the widespread use of subtraction scores, which lack validity due to their contamination with control condition variance. Regressing, rather than subtracting, a control condition from a condition of interest corrects this validity problem by statistically removing all control condition variance, thereby producing a specific measure that is uncorrelated with the control measure. Using 43 participants, we measured the relationships amongst the Cambridge Face Memory Test (CFMT) and two holistic processing measures, the composite task (CT) and the part-whole task (PW). For the holistic processing measures (CT and PW), we contrasted the results for regressing vs. subtracting the control conditions (parts for PW; misaligned congruency effect for CT) from the conditions of interest (wholes for PW; aligned congruency effect for CT). The regression-based holistic processing measures correlated with each other and with CFMT, supporting the idea of a unitary holistic processing mechanism that is involved in skilled face recognition. Subtraction scores yielded weaker correlations, especially for the PW. Together, the regression-based holistic processing measures predicted more than twice the amount of variance in CFMT (R2=.21) than their respective subtraction measures (R2=.10). We conclude that holistic processing is robustly linked to skilled face recognition. In addition to confirming this theoretically significant link, these results provide a case in point for the inappropriateness of subtraction scores when requiring a specific individual differences measure that removes the variance of a control task.

Optimal Control of Production Processes with Variable Execution Times

The paper deals with the optimal control of production processes characterized by the possibility of performing operations (relevant to the processing of a set of jobs) with variable execution times. A production process relevant to a single machine is addressed first. An optimization problem with a quite general cost function is considered, and some properties of optimal solutions are derived. Then, a particular version of the problem is analyzed, in which the cost function is the weighted sum of the quadratic earliness and tardiness of jobs and of quadratic deviations between pre-defined nominal unitary processing times and the actual ones. The decision variables of the problem are the possible idle times inserted before job executions and the processing times of jobs. This single machine problem is stated as an optimal control problem and a closed-loop solution is derived. Then, a second production process is considered, in which multiple machines serve jobs in parallel, again with variable processing times and with different processing costs. With reference to this second production scheme, a significant decision problem refers to the splitting of jobs over the different machines. Then, on the basis of a sensitivity analysis of the single machine problem solution, some conditions to verify the optimality of a pre-defined splitting are derived. An on-line splitting scheme using such conditions is finally presented.

Fast algorithm for surface reconstruction from cloud data based RBF neural network

On the basis of the analysis of the existing reconstruction methods' limitations,a fast neural network based algorithm for 3D surface reconstruction from cloud data was presented.Firstly,a unitary processing for the cloud data was made.And then the contour lines were extracted and the surface based contour lines were segmented.The method can directly from the neural network value matrix get the right curve control points or surface control mesh,and through neural network values restriction achieve the right curve or patch of smooth connection.Experimental results show that this method can quickly obtain good shape Mesh.

Relative Clauses in English conversation

This paper is a usage-based study of the grammar of that set of English Relative Clauses with which a relativizer has been described as optional. We argue that the regularities in the use of relativizers in English can be seen as systematically arising from pragmatic-prosodic factors, creating frequency effects, resulting in some cases highly grammaticized formats: the more the Main Clause and the Relative Clause are integrated with each other, that is, approach monoclausal status, the more likely we are to find no relativizer used; conversely, the more separate the two clauses are, the more likely we are to find an overt relativizer. These findings have led us to suggest that the more monoclausal combinations have become unitary storage and processing chunks. We thus see these findings as a contribution not only to our understanding of Relative Clauses, but to our understanding of syntactic organization in general and of the nature of the grammatical practices in which speakers engage in everyday interactions.

Measuring the development of executive control with the shape school.

Although several neurodevelopmental and psychiatric disorders can emerge during the preschool period, there are comparatively few instruments to assess executive control. Evidence for validity of the Shape School (K. A. Espy, 1997) was examined in a sample of 219 typically developing young children. There was good evidence for validity, as Shape School performance variables were interrelated and were associated to other criterion measures considered to measure aspects of executive control. Also suggesting validity, the Shape School variables varied as a function of whether the task demands (a) were executive, (b) required inhibition of a prepotent response or context-controlled selection among relevant stimulus-response sets, and (c) included unitary or concurrent processing. The Shape School may be an effective tool by which to measure executive control in young children who have atypical developmental patterns.

Imagined viewer and object rotations dissociated with event-related FMRI.

Human spatial reasoning may depend in part on two dissociable types of mental image transformations: object-based transformations, in which an object is imagined to move in space relative to the viewer and the environment, and perspective transformations, in which the viewer imagines the scene from a different vantage point. This study measured local brain activity with event-related fMRI while participants were instructed to either imagine an array of objects rotating (an object-based transformation) or imagine themselves rotating around the array (a perspective transformation). Object-based transformations led to selective increases in right parietal cortex and decreases in left parietal cortex, whereas perspective transformations led to selective increases in left temporal cortex. These results argue against the view that mental image transformations are performed by a unitary neural processing system, and they suggest that different overlapping systems are engaged for different image transformations.

Monotones and invariants for multi-particle quantum states

We introduce new entanglement monotones which generalize, to the case of many parties, those which give rise to the majorization-based partial ordering of bipartite states' entanglement. We give some examples of restrictions they impose on deterministic and probabilistic conversion between multipartite states via local actions and classical communication. These include restrictions which do not follow from any bipartite considerations. We derive supermultiplicativity relations between each state's monotones and the monotones for collective processing when the parties share several states. We also investigate polynomial invariants under local unitary transformations, and show that a large class of these are invariant under collective unitary processing and also multiplicative, putting restrictions, for example, on the exact conversion of multiple copies of one state to multiple copies of another.

Measuring Central Executive Functioning: What's in a Reading Span?

Although variations of Daneman and Carpenter's (1980) Reading Span Test (RST) have seen increasing use in both cognitive and neuropsychological research, the specific mental operations involved in performing it remain unclear. We tested 80 undergraduates to examine the extent to which speed of processing, manipulation capacity, and susceptibility to interference contributed to RST performance. The results suggest that, rather than unitary central executive or processing speed functions underlying RST performance, at least two factors, manipulation capacity and susceptibility to interference, underlie the task. Further study of RST operations may lead to a better understanding of the nature of the central executive itself.

Woorden en Objecten

The semantic system has a central position in the language processing system as the intermediate between language production and language comprehension. The system itself may be separated into distinctive components: visual and lexical semantics. Their is much discussion about the interference between the visual and lexical semantic system and about the quality of the processing routes. Some authors propose a unitary amodal system, other authors plead for modality-specific semantic systems. The stage of perceptual categorization is considered both as optional and as obligatory. The objective of this study is: to investigate visual and lexical semantic processing in aphasic patients (n=74) (control groups: right- hemispheric patients (n=10) and normals (n=96)) (i), to examine the relation between semantic deficits and aphasia type and severity (ii) and to explore the relation between presemantic and semantic visual processing. Instruments to measure presemantic and semantic processing: Object Decision (Riddoch & Humphreys, 1987) and the verbal and visual Semantic Association Test (Visch-Brink e.a.., 1993). Results: aphasie patients as a group were significantly impaired both in Object Decision and visual and verbal semantic processing. Some patients appeared to have a selective deficit in visual or verbal semantic processing (1). No correlation was found between the performance on the visual or verbal Semantic Association Test and the aphasia type or severity (ii). In some patients a dissociation was found between presemantic and semantic visual processing (iii). Conclusions: Visual and lexical semantic processing in aphasia may selectively disturbed, which pleads rather for a multiple than for a unitary semantic processing system. Aphasia type and the severity of aphasia do not function as indicators for the presence of a visual and/or lexical semantic disorder. For the interpretation of the meaning of a picture, the stage of perceptual categorization can be bypassed.

On the Association between Phonological Memory and Receptive Vocabulary in Five-Year-Olds

A large data set was analyzed to reinvestigate the hypothesis that phonological memory, but not phonological sensitivity, accounts for significant variation in young children's receptive vocabulary, against the view that both phonological memory and phonological sensitivity are manifestations of a latent phonological processing ability. Data from 5-year-old preschool children revealed a unitary phonological processing factor underlying phonological memory and phonological sensitivity performance. With age and performance IQ effects controlled, phonological memory was no more strongly associated with receptive vocabulary than was phonological sensitivity. Overall, results were broadly consistent with the latent phonological processing factor account.

Individual differences in learning and memory: A unitary information processing approach

Recent research in the area of individual differences in learning and memory is reviewed from a cognitive perspective. Using the two-state model of memory as a framework, individual variations in attentional, short-term store, and long-term store processes are discussed. The focus is on using individual differences to evaluate nomothetic cognitive models, as well as on using cognitive models in guiding research on individual differences. Both within-individual and between-individual differences in basic processes are examined. In so doing, the importance of strategy choice is stressed using the concept of cognitive flexibility. Several promising directions, both methodological and theoretical, are noted and the value of using specific information processing models in the study of individual differences is emphasized.

Some factors in picture recognition memory.

Summary This paper presents a review and critical analysis of some research findings and conclusions which seem to demonstrate that picture recognition memory is superior to verbal recognition memory. It cautions against accepting these data as evidence for two (picture-verbal) memory systems. Several alternative explanations of the picture-verbal performance discrepancy are derived from interference theory and partial learning theory. “Picture” as a stimulus category is vague and overinclusive. Recognition memory capacity varies from poor to excellent depending on the “pictures,” a fact not in harmony with a memory model employing a unitary processing mechanism for pictorial stimuli. Perceptual constancy is invoked in support of a view that is antagonistic to the implication that the human recognition memory mechanism is error free.