3-5岁幼儿认知灵活性的发展

To test preschoolers’ development of cognitive flexibility--an ability to solve a problem in one way and to then switch solution strategies, and the mechanism involved in the development, 3-5-year-olds are asked to perform switching tasks in which the experimenter manipulates the way the stimuli are presented: consecutive or simultaneous; the way the switching happens: between dimensions or within a dimension; the conceptual domains involved: shape, color, number and direction; the specific labels used. The main results of this work are presented below: (1) 3-5-year-olds’ cognitive flexibility develops with age, yet its development is not of the same speed in extra-dimensional switch tasks and inter-dimensional reversal tasks. 3-year-olds manifest some cognitive flexibility, but their performance is significantly worse than that of 4- and 5-year-olds. For the 3-year-olds, in reversal tasks, although 80% of the children passed the post-switch phrase in color task; less then 60% children passed the post-switch phrase in shape, number and direction tasks. In extra-dimensional tasks, 3-year-olds performance is worse than that in the reversal tasks. Less than 50% of the children passed the tasks. Children’s cognitive flexibility develops fast from 3-year-olds to 4-year-olds. Both 4-year-olds and 5-year-olds demonstrate high flexibility without significant difference between them. (2) Children’s flexibility in the conceptual domains of shape, color, number and direction follows different developing patterns. In inter-dimensional reversal tasks, 3-year-olds’ performance is not the same in the 4 conceptual domains, but the difference among the domains is insignificant in 4-and-5-year-olds. In extra-dimensional switching tasks, children’s performance on the 4 domain tasks is significantly different from one another in 3-, 4-, and 5-year-olds. (3) The way the stimuli are presented affects children’s development of cognitive flexibility. In inter-dimensional reversal tasks, 3-year-olds’ performance in consecutive presentation is significantly better than that in simultaneous presentation. 4- and 5-year-olds’ performance in the 2 presentations is not significantly different from each other. In extra-dimensional switch tasks, 3-, 4-, and 5-year-olds’ performance in the consecutive presentation is not significantly better than that in the simultaneous presentation (4) 3-, 4-, and 5-year-olds’ self-issued labeling aids their performance on the switching tasks. Children’ performance in the labeling condition is significantly better than that of no labeling. (5) 3-5-year-olds’ cognitive flexibility is highly correlated with their working memory and inhibition. Children’ development of cognitive flexibility is a process that involves activation of working memory and inhibition, in which the complexity of the task also plays a role.

细胞外信号调节蛋白激酶-cAMP反应元件结合蛋白信号通路在应激所致抑郁行为障碍中的作用

Stress is the most important factor in the vulnerability to depression and other behavioral disorders, but the mechanisms that stress signals are transferred into depression are far from understanding. To date, the neurotransmitters, neurotrophins and signal pathway have been concerned in the topic focusing on the pathophysiology of depression, but there are still many puzzles. Increasing evidence has indicated that the alteration in neuronal plasticity is the “trace” of stress-induced damages. The extracellular signal-regulated protein kinase(ERK)-cyclic-AMP-responsive element（CRE）-binding protein(CREB)signal pathway is a powerful intracellular signal transduction pathway participating in neuronal plasticity which is involved in higher brain cognitive functions such as learning and memory. However, so far, little is known about the role of the ERK-CREB signal pathway in response to stress and emotional modulations. Thus the aim of the study was to systematically investigate the role of the ERK-CEB signal pathway in depressive-like behaviors induced by stress. Depression animal models, antidepressant agent treatment and disruption of signal pathway in specific brain regions were applied. In the present study, three experiment sessions were designed to make sure whether the ERK-CREB signal pathway was indeed one of pathophysiological mechanisms of depressive-like behaviors induced by stress. In experiment one, two different stress animal models were applied, chronic forced swim stress and chronic empty water bottle stress. After stress, all animals were tested behaviorally using open-field, elevated-plus maze and saccharine preference test, and brain samples were processed for determination of ERK, P-ERK, CREB and P-CREB using western blot. The relationships between the proteins of ERK, P-ERK, CREB and P-CREB in the brain and the behavioral variables were also analyzed. In experiment two, rats were treated with antidepressant agent fluoxetine once a day for 21 consecutive days, then the brain levels of ERK, P-ERK, CREB and P-CREB was determined, the depressive-like behaviors were also examined. In experiment three, mitogen activated extracellular-signal-regulated kinase kinase (MEK) inhibitor U0126 was administrated to inhabit the activation of ERK in the hippocampus and prefrontal cortex respectively, then behavioral measurements and protein detection were conducted. The main results of the study were as the following: (1) Chronic forced swim stress induced animals to suffer depression and disrupted the ERK-CREB signal pathway in hippocampus and prefrontal cortex. There were significant correlations between P-ERK2, P-CREB and multiple variables of depressive-like behaviors. (2) Chronic empty water bottle stress did not induce depressive-like behaviors. Such stress decreased the brain level of P-ERK2 in hippocampus and prefrontal cortex, but the level of P-CREB in the hippocampus was increased. (3) The antidepressant agent fluoxetine relieved depressive-like behaviors and increased the activities of the ERK-CREB signal pathway in stressed animals. (4) Animals treated with U0126 injection into hippocampus showed decreased activities of the ERK-CREB signal pathway in the hippocampus, and suffered depression comorbid with anxiety. (5) Animals treated with U0126 injection into prefrontal cortex showed decreased activities of the ERK-CREB signal pathway in the prefrontal cortex, and exhibited depressive-like behaviors. In conclusion, The ERK-CREB signal pathway in the hippocampus and prefrontal cortex was involved in stress responses and significantly correlated with depressive-like behaviors; The ERK-CREB signal pathway in the hippocampus and prefrontal cortex participated in the mechanism that fluoxetine reversed stress-induced behavioral disorders, and might be the target pathway of the therapeutic action of antidepressants; The disruption of the ERK-CREB signal pathway in the hippocampus or prefrontal cortex led to depressive-like behaviors in animals, suggesting that disruption of ERK-CREB pathway in the hippocampus or prefrontal cortex was involved in the pathophysiology of depression, and might be at least one of the mechanisms of depression induced by stress.

非言语学习不良青少年空间关系推理及其影响因素研究

It has reported that individuals with nonverbal learning disabilities (NLD) have deficits in visual-spatial organization and strengths in rote language abilities. At present, there are few studies on higher order cognitive abilities of adolescents with NLD, such as the reasoning about spatial relations. The study sampled three groups: a normal group (a control group, C), a nonverbal learning disabilities group (NLD), and a verbal learning disabilities group (VLD). The aim of this study was to examine spatial and nonspatial relation reasoning abilities in adolescents with NLD under figure and word conditions, and assessed the relative involvement of different working memory components in four types of reasoning tasks: reasoning about figure-spatial, figure-nonspatial, verbal-spatial, and verbal-nonspatial relations. Using the double-tasks methodology, visual, spatial, central-executive, and phonological loads were realized. We tried to find how working memory components impact on adolescents with NLD spatial and nonspatial reasoning. The main results of present research are as follows. (1) The NLD group didn’t differ from normal group on reasoning about figure-nonspatial relations. The NLD group scored lower than the C group in spatial problems. So, adolescents with NLD showed a dissociation between spatial and non-spatial relation reasoning. They scored higher in non-spatial problems than in spatial ones. Adolescents with VLD developed well in reasoning about figure-nonspatial relations, but showed deficits in other three tasks. (2) For each reasoning task, the difficult of four types of reasoning problem had different changing trend. For figure and verbal spatial problems, mental model approach can interpret performance of the four problems well. For verbal nonspatial problems, a logical rule approach can interpret performance of the four problems well. (3) Adolescents with NLD did not differ from adolescents with VLD and normal adolescents in phonological, central-executive, and visual dual tasks. But the NLD group had lower performance than the other two groups in spatial dual task. The results showed a dissociation between visual and spatial working memory in NLD group. The VLD group only experienced deficits in central-executive subsystem. (4) The studies found that spatial reasoning mainly loaded spatial working memory, whist the involvement of spatial resources in nonspatial reasoning was little. Visual working memory mainly involved in reasoning about spatial and figure-nonspatial relations, especially in figure-nonspatial problems, and had few impacts on verbal-nonspatial reasoning. Central executive system was involved in all reasoning tasks. The role of phonological loop in the reasoning tasks required further explored. (5) According to the findings, we concluded that the deficits in spatial working memory resulted in poor spatial reasoning abilities for teenagers with NLD, whist because of the limited central executive capability, teenagers with VLD showed poor reasoning abilities. (6) The three groups can used multiple strategies during the reasoning process. They didn’t differ from each other in reasoning strategies. They all used mental model strategy to solve figure and verbal spatial problems, and used logic rule strategy to solve verbal nonspatial problems.

空间及言语工作记忆任务的情绪效应：来自ERP/ fMRI的证据

In the present study, based on processing efficiency theory, we used the event-related potentials (ERP) and functional magnetic resonance image (fMRI) techniques to explore the underlying neutral mechanism of influences of negative emotion on three subsystems of working memory, phonological loop、 visuospatial sketh pad and the central executive. The modified DSMT (delayed matching-to-sample task) and n-back tasks were adopted and IAPS (International Affective Picture System) pictures were employed to induce the expected emotional state of subjects. The main results and conclusions obtained in the series of experiments are as the following: 1. In DSM tasks, we found P200 and P300 were reduced by negative emotion in both spatial and verbal tasks, however the increased negative slow wave were only observed in spatial tasks, not in verbal tasks. 2. In n-back tasks, the updating function of WM associated P300 was affected by negative emotion only in spatial tasks, not in verbal tasks. Current density analysis revealed strong current density in the fronto-parietal cortex only in the spatial tasks as well. 3. We adopted fMRI-block design and ROIs analysis, and found significant emotion and task effects in spatial WM-associated right superior parietal cortex; only emotion effect in verbal WM-associated Broca’s area; the interaction effect in attention-associated medial prefrontal area and bilateral inferior parietal cortex. These results implied the negative emotion mainly disturbed the spatial WM-related areas, and the attention control system play a key role in the interaction of spatial WM and negative emotion. 4. to further examine the effects of positive、negative and neutral emotion on tasks with different cognitive loads, the selective effect of emotion on the ERP components of spatial WM was only found in 2-back tasks, not in visual searching tasks. So, firstly the positive emotion as well as negative emotion selectively disturbed on spatial WM in light of the attention resource competition mechanism. Secondly, the selective influences based on the different WM systems, not the properties of spatial and verbal information. At last, the manner of the interaction of emotion and cognition is correlated with the cognitive load.

影响汉语阅读能力发展的相关认知因素及其作用的发展变化

The present cross-sectional study paid attention to Chinese reading acquisition of 391 children from preschool to grade 3 in two elementary schools, and investigated the relationship between orthographic processing skills, morphological awareness, phonological awareness, naming, phonological memory, visual processing skill and reading skills, after controlling the variance of age, nonverbal intelligence and pinyin knowledge. The main results are as follows: Firstly, there are many different language skills as the predictors of Chinese reading success. Orthographic processing skills, morphological awareness, phonological awareness and naming are important in single-character recognition and comprehension. Beside them, the effect of visual processing skill and phonological memory for comprehension are also significant. Among them, the role of orthographic processing skills is the most important, whatever in single-character recognition or in comprehension. Secondly, orthographic processing skills are the most important factors in reading acquisition at low grade and its effect drops obviously after grade 2. Thirdly, morphological awareness is also the factor that cannot be ignored whatever for single-character recognition or for comprehension. Its influence appears in preschool and becomes the only significant predictor of character recognition in grade 3. Furthermore, morphological awareness is more relevant with the development of comprehension. Fourthly, phonological awareness plays the secondary role in Chinese reading acquisition except in grade 2 when its contribution is most of all. And compare with morphological awareness, the effect of phonological awareness is relative low. Fifthly, naming is important through preschool to grade 2. The contribution of phonological memory increases from preschool to grade 3 in comprehension.

应用解析水平理论考察时间距离对决策的影响

Construal Level Theory is a kind of social cognitive theory, with the main conclusion of that the more time distance is, the more people use high level construal and the more high level construal affect in judging, decision making and such of these cognitive processes, and the low level construal has the mirror process as well. In these ten years, construal level theory is developing very fast and some of the researches of consumer behavior has concerned this developed trend very much. In 2007’s Journal of Consumer psychology, half of the papers focused on construal topics and ask for more researches about these topics. So our research mainly focused on such topics, the application of construal level theory in consumer behavior research. The first part is contained 3 experiments which mean to discuss the questions from reviewing the prior literatures. The research methods, manipulated definition, construal level factors VS construal level events are the goal of first part of this study. The results showed that construal level’s effect might be a consecutive variable and has a consecutive trend when time goes by. Time distance might not be a semantic cognitive effect to construal level but a internal ones for when there’s no verbal information of time distance the results would have the same one as well. The second part of the study is focus on a simplified model of decision-making, which contained two times decision-making, to detect whether and how would the prior decision making affect the next decision making. The study conducted the time distance in first decision making with the situation for the decision and conducted the second time distance in the time distance between the two decision situations. Although we couldn’t get the detail of the weight changes in construal level factors limited by our research, we can have a logical hypothesis based on “one-down- the other-up”. The results showed that the level of construal factors can affect the memory and the more the factors affected, the bigger the error would be. The first time distance and second time distance could effect the second decision in a interaction-way, and support the hypothesis. The whole research is mean to explore the application of construal level theory in consumer behavior research. The conclusion suggests that the periods of products and the consuming may need different marketing strategies in a long-term perspective and time distance should be control are detected in marketing analysis even there’s no time information on the paper.

心理旋转中的整体优先效应及其机制

In the history of psychology research, more attention had been focused on the relation between local processing and global processing. For the global information and the local information, which is processed earlier? And which is processed faster? Precedence of the global over the local level in visual perception has been well established by Navon with compound stimuli, and Navon’s original study gave rise to many publications, including replications, generalization to other kinds of stimuli (nonverbal material, digits), populations (infants, children, brain-damaged subjects), and tasks (lateral visual hemifield presentation, copy drawing, memory recognition, and recall), and triggered some debate about the conditions in which global precedence is and is not observed (number, size, sparsity, and goodness of the stimuli, exposure duration, etc.). However, whether there is a global advantage or precedence in other cognitive processes was less tested. Most researches had suggested that there was a functional equivalency between visual perception and visual image processing. However, it’s still unknown whether there will be a global advantage on mental rotation. In the present study, we combined the mental rotation task with the compound stimuli to explore whether the global or local advantage also existed at the mental imagery transformation stages. In two pilot studies, the perceptual global precedence was found to be present in a normal/mirror-image judgment task when the stimuli exposure time was short; while the stimuli exposure time was prolonged (stimuli kept available till subjects’ response) the perceptual global precedence was showed to be eliminated. In all of the subsequent experiments, stimili would be presented till subjects’ response. Then mental rotation was added in normal/mirror-image judgment (some of the stimuli were rotated to certain angles from upright) in normal experiments, experiment 1 and 2 observed a global advantage on mental rotation both with a focused-attention design (Experiment 1) and divided-attention design (Experiment 2). Subjects’ reaction times were increased with rotation angles, and the accuracy was decreased with rotation angles, suggesting that subject need a mental rotation to make a normal/mirror judgment. The most important results were that subjects’ response to global rotation was faster than that to local rotation. The analysis of slope of rotation further indicated that, to some extend, the speed of global rotation was faster than that of local rotation. These results suggest a global advantage on mental rotation. Experiment 3 took advantage of the high temporal resolution of event-related potentials to explore the temporal pattern of global advantage on mental rotation. Event-related potential results indicated the parietal P300 amplitude was inversely related to the character orientation, and the local rotation task delayed the onset of the mental-rotation-related negativity at parietal electrodes. None clear effect was found for occipital N150. All these results suggested that the global rotation was not only processed faster than local rotation, but also occurred earlier than local rotation. Experiments 4 and 5 took the effect size of global advantage as the main dependent variable, and visual angle and exposure duration of the stimuli as independent variables, to examine the relationship between perceptual global precedence and global advantage on mental rotation. Results indicated that visual angle and exposure duration did not influence the effect size of global advantage on mental rotation. The global advantage on mental rotation and the perceptual global advantage seemed to be independent but their effects could be accumulated at some condition. These findings not only contribute to revealing a new processing property of mental rotation, but also deepen our understanding of the problem of global/local processing and shed light on the debate on locus of global precedence.

嵌套式空间中物体空间关系的表征和提取

In human memory, a large environment is divided into several small trunks. Each trunk is represented separately. So it formed a hierarchical representation of the large environment. Carlson-Radvansky & Jiang (1998) reported that different environments may be encoded in different spatial reference frames, and accessing an environmental representation requires activating the corresponding reference frame. According to the theory of intrinsic frames of reference proposed by Mou and his college, people organize the spatial relations of the objects in an environment relative to the intrinsic frames of reference in their representation. Our study focus on how people retrieval the spatial relations of objects in two nested spaces when they do the JRD task. The main findings of our study are: a) In two nested spaces, the objects in each space are represented relative to the intrinsic reference direction of that space. And people’s retrieval of the spatial relations between the objects in the same space according to the recovery and retrieval of the intrinsic reference direction of that space. b) In the JRD task, when retrieval the spatial relationships of objects in different spaces, the performance is depend on the recovery and retrieval of the intrinsic reference direction of the space that the target object in. c) After people retrieval of the spatial relations of objects in different spaces depends on the recovery of the intrinsic reference frame of one of the space, it was very hard for them to use the intrinsic frame of reference frame of the other space in retrieval the spatial relations of objects.

汉语句子和语篇韵律层级边界的认知加工及其ERP效应

The aim of the present study was to explore whether the CPS (Closure Positive Shift) which reflected prosodic processing will be elicited when listeners perceived different hierarchical prosodic boundaries in Chinese sentence and discourse (Quatrain). In addiction, the similarity and difference in amplitude, onset latency and scalp distribution between these CPS were investigated. The nature of the CPS and its relationship to acoustic parameters was also explored systematically. The main results and conclusions of the present study were: (1) Phonological phrase boundaries and intonational phrase boundaries in Chinese sentences both elicited the CPS; however, phonological word boundaries can't evoke it. The CPS induced by phonological phrase boundaries was earlier than the one related to intonational phrase boundaries in onset latency, and the amplitude was also somewhat lower. When the pauses in the vicinity of these two boundaries were removed, the onset latency difference disappeared while amplitude in the new conditions was also lower. This indicates that whenever listeners segment sentence into phrases, the CPS will be elicited. Besides, pause was not the decisive factor to elicit the CPS, but can modify its onset latency and amplitude effectively. (2) The different hierarchical prosodic boundaries in seven character quatrain including phonological phrase boundaries, intonational phrase boundaries and sentence pair boundaries elicited the CPS respectively. Furthermore, just like in the sentence level, onset latency of the CPS induced by the prosodic boundaries in the discourse was also influenced by the length of pause: the shorter the pause was, the earlier the onset latency. For the comparison between the CPS evoked by the same and different hierarchical prosodic boundaries, its amplitude was influenced by the extent to which prosodic representations were activated. Thus, the condition of the CPS elicitation was extended to the prosodic bounaries in discourse, and further indicated that it was influenced by acoustic parameters. (3) No matter what task the participants completed, just like word detection or rythem matching task, the CPS will be evoked. However, its amplitude was larger in the anterior region, when listeners completed the word detection task which needed more attention and higher load of working memory. The present result indicated that the elicitation of the CPS was not influenced by the task the participants completed, but different task influence its scalp distribution. (4) The final syllable of the sentence and quatrain can't elicit the CPS, but a P300-like positive component. Although the scalp distribution was similar to the CPS, it was much higher in amplitude. The present result suggested that only the prosodic boundaries reflecting not only the closure of the former prosodic unit but also integrating the later one will elicit the CPS.

老化态度对老年人记忆作业影响的研究

It was a study of the effect of non-cognitive factors on cognitive aging. The purpose of the study was to research the effect of attitude towards aging on memory performance of the elderly, and trying to explore the mechanism of the attitude towards aging on memory performance. The entire study was divided into three phases and included six experiments. The questionnaire of attitude towards aging was compiled in phase 1. Then the validity and reliability of it was tested in the elderly. The self-esteem scale was also tested as above. These prepare the instruments for the study. It was a static study in phase 2. Through comparing the old groups in different environment, analyzing relationship between different non-cognitive factors and memory performance in the old subjects in identical environment, the paths of the effect of the attitude towards aging on memory performance was explored. It was a dynamic study in phase 3. By changing attitude towards aging of the elderly with direct thinking (positive, negative), the effect on memory performance was observed and the mechanism was explored. Main results: 1. The validity and reliability of the questionnaire towards aging were good. Its construct had two factors (positive, negative). Both reliability of retest and split test were over 0.90. 2. Direct thinking task was able to change the attitude towards aging effectively in old or young adults. The scores of the attitudes towards aging between positive and negative thinking subjects were different significantly. 3. The effect of attitude towards aging on memory performance was significant. The results in static or dynamic condition showed that the elderly with higher score of the questionnaire of attitude towards aging (more positive), their memory self-efficacy and memory performance were higher. In the opposite (negative), they were lower. 4. Mechanism of the effect of the attitude towards aging on memory performance: in static condition there were two paths i.e. direct path and through memory self-efficacy; in dynamic condition, besides the two paths, emotion change constituted another path. 5. Different non-cognitive factors have different effect on psychological function. The results of this study found that self-esteem has no significant correlation with memory performance, but correlates with depression; The factor of education has effect on many non-cognitive factors and memory performance.

记忆年老化与焦虑

It is well established that memory functioning deteriorates with advancing age. However, research indicates that the magnitude of age-related memory deficits varies across different types of memory, and broad individual differences can be observed in the rate and timing of memory aging. The general aim of this study was to investigate the selectivity and variability of memory functioning in relation to anxiety. Firstly, memory effectiveness was assessed in episodic memory tasks with reality monitoring and external source monitoring paradigms, semantic memory tasks referred to general knowledge and word fluency, and perceptual priming task reflected in word completion. According to the scores on trait version of STAI, the high-trait and low-trait anxious subjects were screened respectively from young and old participants matched for educational level. Secondly, based on the results of the first part, concurrent primary and secondary tasks with probe technique assessing spare processing capacity were used to explore the relation between memory efficiency and anxiety. The first main findings were that: (a) there were no age-related differences in semantic memory assessed by general knowledge and PRS, whereas age effects were observed in episodic memory and semantic memory assessed by word fluency with stringent time restraints. (b) Furthermore, comparison of age-related deficits in source and item was not related to the presentation ways and encoding effort for source, but was affected by types of source. Specifically, memory was more sensitive to aging than item memory in external source monitoring processes involved in discriminating two external sources (i.e., female vs. male voices), but not in reality monitoring processes in discriminating between internal and external sources (i.e., acting vs. listening). The second main findings were that: (a) Anxiety had no effects on the effectiveness and efficiency of semantic memory in recall of general knowledge and PRS, but impaired those of semantic memory in word fluency. (b) The effects of anxiety on episodic memory were different between the old and the young. Both the effectiveness and the efficiency of episodic memory of the old were affected adversely by anxiety. More importantly, source recall in external source monitoring processes was observed to be more vulnerable to anxiety than item memory. The effectiveness of episodic memory of the young was relatively unrelated to anxiety, while anxiety might have adverse effect on their memory efficiency. These results indicated that: First, the selectivity of age-related memory deficits existed not only between memory systems, but also within episodic memory system. The tendency to forget the source even when the fact was retained in external source monitoring was suggested to be a specific feature of cognitive aging. Second, anxiety had adverse impact on the individual differences in memory aging, and mediated partial age-related differences in episodic memory performance.

A Theory of How the Brain Might Work

I wish to propose a quite speculative new version of the grandmother cell theory to explain how the brain, or parts of it, may work. In particular, I discuss how the visual system may learn to recognize 3D objects. The model would apply directly to the cortical cells involved in visual face recognition. I will also outline the relation of our theory to existing models of the cerebellum and of motor control. Specific biophysical mechanisms can be readily suggested as part of a basic type of neural circuitry that can learn to approximate multidimensional input-output mappings from sets of examples and that is expected to be replicated in different regions of the brain and across modalities. The main points of the theory are: -the brain uses modules for multivariate function approximation as basic components of several of its information processing subsystems. -these modules are realized as HyperBF networks (Poggio and Girosi, 1990a,b). -HyperBF networks can be implemented in terms of biologically plausible mechanisms and circuitry. The theory predicts a specific type of population coding that represents an extension of schemes such as look-up tables. I will conclude with some speculations about the trade-off between memory and computation and the evolution of intelligence.

Persistent Nodes for Reliable Memory in Geographically Local Networks

A Persistent Node is a redundant distributed mechanism for storing a key/value pair reliably in a geographically local network. In this paper, I develop a method of establishing Persistent Nodes in an amorphous matrix. I address issues of construction, usage, atomicity guarantees and reliability in the face of stopping failures. Applications include routing, congestion control, and data storage in gigascale networks.

A Parallel Crossbar Routing Chip for a Shared Memory Multiprocessor

This thesis describes the design and implementation of an integrated circuit and associated packaging to be used as the building block for the data routing network of a large scale shared memory multiprocessor system. A general purpose multiprocessor depends on high-bandwidth, low-latency communications between computing elements. This thesis describes the design and construction of RN1, a novel self-routing, enhanced crossbar switch as a CMOS VLSI chip. This chip provides the basic building block for a scalable pipelined routing network with byte-wide data channels. A series of RN1 chips can be cascaded with no additional internal network components to form a multistage fault-tolerant routing switch. The chip is designed to operate at clock frequencies up to 100Mhz using Hewlett-Packard's HP34 $1.2\\mu$ process. This aggressive performance goal demands that special attention be paid to optimization of the logic architecture and circuit design.