Programming from metaphorisms

Unfolds generate data structures, and folds consume them. A hylomorphism is a fold after an unfold, generating then consuming a virtual data structure. A metamorphism is the opposite composition, an unfold after a fold; typically, it will convert from one data representation to another. In general, metamorphisms are less interesting than hylomorphisms: there is no automatic fusion to deforest the intermediate virtual data structure. However, under certain conditions fusion is possible: some of the work of the unfold can be done before all of the work of the fold is complete. This permits streaming metamorphisms, and among other things allows conversion of infinite data representations. We present a theory of metamorphisms and outline some examples.

Summary This paper considers the receding horizon tracking control of the unicycle-type robot subject to coupled input constraint based on virtual structure. The tracking position of the follower is considered to be a virtual structure point with respect to a Frenet–Serret frame fixed on the leader, and the desired control input of the follower not only depend on the input of the leader but also the separation vector. Firstly, a sufficient input condition for the leader robot is given to enable the follower to track its desired position while satisfying its inputs constraint. Secondly, receding horizon control scheme is designed for the follower robot, in which the recursive feasibility is guaranteed by developing a diamond-shaped positively invariant terminal-state region and its corresponding controller. Finally, simulation results are provided to verify the effectiveness of the scheme proposed. Copyright © 2016 John Wiley & Sons, Ltd.

A brief analysis of character strings and string processing is given. Text processing is defined as the processing of character strings to control not only the sequential relations among the characters, but also spatial and form relations among the symbols used to produce a physical display of the character string. Requirements are given for a data structure by which character strings may be represented to facilitate text processing, including independent manipulation of sequential, spatial, and form relations. A Text Processing Code (TPC) meeting these requirements is presented in detail. Several other coding schemes are examined and shown to be inadequate for text processing as defined here.

The problem of managing evolving data has attracted considerable research attention. Researchers have focused on the modeling and querying of schema/instance-level structural changes, such as, addition, deletion and modification of attributes. Databases with such a functionality are known as temporal databases. A limitation of the temporal databases is that they treat changes as independent events, while often the appearance (or elimination) of some structure in the database is the result of an evolution of some existing structure. We claim that maintaining the causal relationship between the two structures is of major importance since it allows additional reasoning to be performed and answers to be generated for queries that previously had no answers. We present here a novel framework for exploiting the evolution relationships between the structures in the database. In particular, our system combines different structures that are associated through evolution relationships into virtual structures to be used during query answering. The virtual structures define database instances, in a fashion similar to the possible worlds in the probabilistic databases. The framework includes a query answering mechanism that allows queries to be answered over these possible databases without materializing them. Evaluation of such queries raises many interesting technical challenges, since it requires the discovery of Steiner forests on the evolution graphs. On this problem we have designed and implemented a new dynamic programming algorithm with exponential complexity in the size of the input query and polynomial complexity in terms of both the attribute and the evolution data sizes.

BackgroundNew daily persistent headache (NDPH) is a rare but debilitating primary headache disorder that poses a significant burden on individuals and society. Despite its clinical importance, the underlying pathophysiological mechanisms of NDPH remain unclear. In this study, we aimed to investigate the brain structural changes and neural activity patterns in patients with NDPH using multimodal brain imaging analysis of structural magnetic resonance imaging (sMRI) combined with magnetoencephalography (MEG).MethodsTwenty-eight patients with NDPH and 37 healthy controls (HCs) were recruited for this study, and their structural and resting-state data were collected by 3.0 Tesla MRI and MEG. We analyzed the brain morphology using voxel-based morphometry and source-based morphometry. In each brain region, MEG sensor signals from 1 to 200 Hz were analyzed using an adapted version of Welch's method. MEG source localization was conducted using the dynamic statistical parametric mapping, and the difference of source distribution between patients with NDPH and HCs was examined.ResultsOur results revealed significant differences in the regional grey matter volume, cortical thickness, and cortical surface area between the two groups. Specifically, compared with HCs, patients with NDPH showed a significant decrease in cortical thickness of the left rostral cortex in the middle frontal gyrus, decreased cortical surface area of the left fusiform gyrus, decreased grey matter volume of the left superior frontal gyrus and the left middle frontal gyrus, and increased grey matter volume of the left calcarine. Furthermore, the power of the whole brain, bilateral frontal lobes, and right temporal lobe in the NDPH group were higher than that in HCs in the ripple frequency band (80-200 Hz). Functional and structural analysis suggested that there were structural changes and abnormal high frequency cortical activity in both frontal and temporal lobes in patients with NDPH.ConclusionOur findings indicated that patients with NDPH have abnormalities in brain morphology, such as cortical area, cortical thickness, and grey matter volume, accompanied by abnormal cortical neural activity. Brain structural changes in the frontotemporal cortex and abnormalities in cortical ripple activity may be involved in the pathogenesis of NDPH.

Output parameterization based on invariant relative degree

The authors examined whether relevance instructions compensate for differences in verbal ability on measures of reading time, text recall, and sentence recognition. College students (n = 81) with higher and lower verbal ability were assigned randomly to 1 of 2 relevance-instruction conditions before reading a text. They asked participants in each condition to focus on different categories of information within the same text. Relevant information took longer to read and was recalled and recognized better than nonrelevant information. Readers with higher verbal ability read faster and recalled and recognized more information correctly than did those readers with lower verbal ability. Results support the noncompensatory hypothesis, which states that relevance instructions and verbal ability make independent contributions to resource allocation and learning. Readers with lower verbal ability may need additional support even when given prereading relevance instructions.

A formal analysis of the spatial economic structure of the EC requires the integration of input–output data and intra-EC trade data. Such data are available in a set of intercounty EC input–output tables for 1970, 1975 and 1980. The present paper employs a hierarchical decomposition of intercounty economic transactions into selj-affecting feedback loops. The first two intercountry feedback loops for 1975 have the same structure but show opposite directions of the intercountry flows. They break up into two smaller subloops. The first subloop includes 40% of the overall intercountry flows and consists of (West) Germany, France, The Netherlands and Belgium/Luxembourg. The second subloop includes 5% and consists of Italy, the UK, Denmark and Ireland. Hence, the analysis reveals a remarkable core-ring hierarchy. The core is shown to be present in 1970 also, but the 1975 ring dissolves in 1980 when the three new member states become better integrated with the rest of the EC.

A hotel management information system requires a storage and retrieval subsystem for text and image information, but the information is held in heterogeneous databases in a local network environment. Application sharing information will become a key component of synchronous groupware computers and will permit the simultaneous use of off-the-shelf applications such as text processors and spreadsheets by a group of cooperating users. Special software is inserted between application and multiplex input streams. Application output and user input have to be converted between different image and window systems. This paper introduces the concepts of application sharing, image stream conversion and their combination. It presents two sharing systems with integrated image conversion enabling the concurrent use of a single user application and the use of multiple window displays.

Global Gene Expression Patterns in Mouse Wolffian Duct Development

A growing line of research makes use of structural changes and different volatility regimes found in the data in a constructive manner to improve the identification of structural parameters in structural vector autoregressions (SVARs). A standard assumption made in the literature is that the reduced form unconditional error covariance matrix varies while the structural parameters remain constant. Under this hypothesis, it is possible to identify the SVAR without needing to resort to additional restrictions. With macroeconomic data, the assumption that the transmission mechanism of the shocks does not vary across volatility regimes is debatable. We derive novel necessary and sufficient rank conditions for local identification of SVARs, where both the error covariance matrix and the structural parameters are allowed to change across volatility regimes. Our approach generalizes the existing literature on ‘identification through changes in volatility’ to a broader framework and opens up interesting possibilities for practitioners. An empirical illustration focuses on a small monetary policy SVAR of the US economy and suggests that monetary policy has become more effective at stabilizing the economy since the 1980s.

Previous research has demonstrated that readers routinely maintain both local and global coherence. Four experiments are presented that test 2 views of how relevant global information becomes readily available to the reader. According to 1 view, readers make use of discourse pointers. These pointers restrict reactivation of backgrounded information to information that is scenario relevant. In contrast, according to the memory‐based text processing view, backgrounded information becomes available through a passive, fast‐acting resonance process. Information becomes available as a function of its degree of featural overlap with the current contents of working memory; relevance of that information is not a factor. The results of all 4 experiments demonstrated that backgrounded information became readily available to the reader if it shared features in common with the current contents of working memory. This occurred independent of whether the information was relevant or thematically related; comprehension was only affected if the reactivated information was scenario relevant.

Professionals involved in the creation of text-based communication face a number of challenges. These include overburdened and often uninterested users juxtaposed with the writer's desire to communicate relevant topical information. Uninvolved users are likely to ignore the message. This may be exacerbated by increases in text length designed to increase the amount and/or detail of information to be communicated. An experiment was conducted to examine the effect of rhetorical figures in text headings as to how users read and process the text (hereafter readership, as used in marketing). To the extent that higher levels of text readership increase user knowledge and skills, enhance topic-related attitudes, and facilitate beneficial topic-related behaviors, higher readership should yield desirable communication outcomes. Headings with rhetorical figures were hypothesized to enhance readership, particularly under conditions generally associated with relatively low readership, namely, lower perceived information relevance and longer text. Results generally support rhetorical figures' abilities to enhance readership, especially with longer texts.

BackgroundPatients with amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD) show functional and structural connectivity alterations in the default mode network (DMN) while cerebrovascular disease (CeVD) shows functional and structural connectivity changes in the executive control network (ECN). Such disruptions are associated with memory and executive function impairment, respectively. Concurrent AD and CeVD pathology is associated with a higher rate of cognitive decline and differential neurodegenerative patterns. Together, such findings are likely reflective of different underlying pathology in AD with and without CeVD. However, few studies have examined the effect of CeVD on network functional connectivity (task-free functional magnetic resonance imaging (fMRI)) and structural connectivity (diffusion MRI) of the DMN and ECN in aMCI and AD using a hypothesis-driven multiple seed-based approach.MethodsWe examined functional and structural connectivity network changes in 39 aMCI, 50 aMCI+CeVD, 47 AD, 47 AD+CeVD, and 65 healthy controls (HCs) and their associations with cognitive impairment in the executive/attention and memory domains.ResultsWe demonstrate divergent DMN and ECN functional connectivity changes in CeVD and non-CeVD subjects. Compared with controls, intra-DMN hippocampal functional connectivity reductions were observed in both AD and AD+CeVD, while intra-DMN parietal and medial prefrontal-parietal functional connectivity was higher in AD+CeVD and aMCI+CeVD, but lower in AD. Intra-ECN frontal functional connectivity increases and fronto-parietal functional connectivity decreases occurred in CeVD but not non-CeVD subjects. Such functional connectivity alterations were related with cognitive impairment in a dissociative manner: intra-DMN functional connectivity changes were associated with worse cognition primarily in non-CeVD groups, while intra-ECN functional connectivity changes were associated with worse cognition primarily in CeVD groups. Additionally, CeVD and non-CeVD groups showed overlapping and distinct alterations in inter-network DMN-ECN functional connectivity depending on disease severity. In contrast to functional connectivity, CeVD groups had greater network structural connectivity damage compared with non-CeVD groups in both aMCI and AD patients. Network structural connectivity damage was associated with worse cognition.ConclusionsWe demonstrate differential functional and structural network changes between aMCI and AD patients with and without CeVD through diverging and deleterious network-based degeneration underlying domain-specific cognitive impairment.

Stability analysis of nontrivial stationary solution and constant equilibrium point of reaction–diffusion neural networks with time delays under Dirichlet zero boundary value