Temporal Episodes Research Articles

Asymmetric adaptivity induces recurrent synchronization in complex networks.

Rhythmic activities that alternate between coherent and incoherent phases are ubiquitous in chemical, ecological, climate, or neural systems. Despite their importance, general mechanisms for their emergence are little understood. In order to fill this gap, we present a framework for describing the emergence of recurrent synchronization in complex networks with adaptive interactions. This phenomenon is manifested at the macroscopic level by temporal episodes of coherent and incoherent dynamics that alternate recurrently. At the same time, the dynamics of the individual nodes do not change qualitatively. We identify asymmetric adaptation rules and temporal separation between the adaptation and the dynamics of individual nodes as key features for the emergence of recurrent synchronization. Our results suggest that asymmetric adaptation might be a fundamental ingredient for recurrent synchronization phenomena as seen in pattern generators, e.g., in neuronal systems.

Autoamputation of the uterine adnexa due to torsion

Uterine adnexa torsion is an urgent surgical condition defined as total or partial twisting of an ovary and/or a fallopian tube on its vascular axis, causing circulatory failure. The diagnosis establishing before the operation is difficult due to absence of pathognomonic features of the clinical picture and instrumental diagnostics. In case of torsion the ovary is usually rotating around the infundibular-pelvic and uterine-ovarian ligaments, which causes vascular compression; ischemia and necrosis are progressing, leading to such complications as pelvithrombophlebitis, bleeding, infections, peritonitis, as well as calcification and autoamputation. Classical clinical picture of the uterine adnexa torsion is a sudden onset of continuous/intermittent pelvic or abdominal pain varying from moderate to severe, diffuse or isolated on one side. Pain syndrome could be of various duration, from several days to several months, and there could be such temporal episodes of pain in past history indicating prior partial torsion. This state can be accompanied by nausea, vomiting, fever, painful and frequent urination. The most precise instrumental diagnostics method in case of uterine adnexa torsion is colour Doppler ultrasonography, however, the final diagnosis is established only during the surgery. If the ovary is ischemic, adnexal detorsion is recommended, in case of necrosis adnexectomy is performed. When examining ultrasound of the pelvic organs, the left ovary is not visualized.
 In our clinical case, according to the results of MRI of pelvic organs, the 38-year old patient had a cyst in posterior cul-de-sac with hemorrhagic or high-protein contents, and also the left ovary was not visible. During the laparoscopy an autoamputation of the left uterine adnexa due to torsion was found, as well as presence of necrotizing lesion in posterior cul-de-sac. Thus, laparoscopy is the only reliable method for diagnosing and treating adnexal torsion.

Geochemical patterns of late Cenozoic intraplate basaltic volcanism in northern New Zealand and their relationship to the behaviour of the mantle

ABSTRACT A major period of subduction-related volcanism in northern New Zealand began about 20 million years ago; its locus of activity migrated southward during the late Cenozoic in response to changes in convergence between the Australian and Pacific tectonic plates. As the volcanic arc migrated, six discrete fields of small-scale basaltic volcanoes were established behind the subduction system. These volcanoes show geochemical characteristics that reveal patterns of mantle behaviour linked to the rapidly evolving plate tectonic environment of Zealandia. Two northern volcano fields began activity about 8 million years ago and have been active into recent times; their chemical compositions reflect partial melting of shallow mantle and their spatial relationships an essentially static source environment. In contrast, four southern fields are dominated by alkalic magmas that likely ascended rapidly from garnet-bearing asthenospheric sources in a northward migrating pattern of discrete temporal episodes (∼1 ma duration) since 3 Ma. The Northland fields were sourced in mantle that became coupled to the lithosphere and have remained active during the last 8 Ma. The Auckland fields are interpreted to reflect independent actively rising asthenospheric mini-plumes linked to mantle convection associated with but geochemically distinct from the subduction system beneath central North Island New Zealand.

The oscillating body: an enactive approach to the embodiment of emotions

The aim of this paper is to advance, within the framework of enactivism, towards a more radically embodied and situated theory of emotions and, in general, of affectivity. Its starting point is that of discussing the well-established notion of bodily resonance (Fuchs 2013, Fuchs & Koch 2014, Fuchs 2018) and the primordial affectivity approach (Colombetti 2014). I will incorporate John Dewey’s theory of emotions, and recent models and empirical finding from cognitive science on the relation between perception and bodily activity (Azzalini, Rebollo & Tallon-Baudry 2019; Allen et al. 2019). The novel element proposed in this paper is taking into consideration the role of bodily oscillatory activity in the perceptual side of cognition through phenomena of relative coordination. This concept from dynamical systems theory allows for an enactivist view of emotions as temporal episodes triggered by a tension that affects the rhythmic interaction between brain, body, and environment. By defending the importance of this enacted rhythm, the body emerges as a truly active agent, gating and modulating affectivity during all the stages of the sensorimotor circuit from perception to action.

Learning to Love Krishna: A Living Theology of Moral Emotions

ABSTRACTThis article explores what I describe as a living theology of moral emotions in the context of a multi-national community of ISKCON (International Society for Krishna Consciousness) devotees in Mayapur, West Bengal. Against the backdrop of a rich history of moralisation of emotions, I outline how ISKCON’s philosophy has been informed by the context of its cross-cultural transmission to the West and back again to India. In particular, I focus on how devotees manage the seeming impossibility of the central spiritual goal of prema (‘pure love for Krishna’). Through a focus on moral narratives that cohere around understandings of emotion, I suggest that the careful aversion to displays, or indeed claims, of overt emotional experience in Mayapur is best understood by treating emotions as sites of moral self-cultivation. Whereas the anthropology of emotions has tended to privilege temporal episodes of rupture, I argue that more attention needs to be paid to how emotions are conceived and managed in the context of broader sustained projects of self-transformation.

German economic and social sciences between the national and the transnational: The Verein für Sozialpolitik, 1872–1952

AbstractThe Verein für Sozialpolitik is the preeminent organization of German‐speaking economists in the world. Aside from a brief interruption between during the Nazi period, it has been central in the development of the economic and social sciences in Germany, Austria, and Switzerland but also globally, since 1872. However, historical scholarship on the Verein has been narrowly focused on different thematic or temporal episodes that emphasize conceptual, generational, or political breaks in Germany's turbulent history. This essay gives a brief historical overview of the Verein and the historical literature. It calls for a re‐evaluation that highlights the persistence of the organization as it navigated between national and transnational developments.

Oxygen isotope and trace element evidence for three-stage petrogenesis of the youngest episode (260–79 ka) of Yellowstone rhyolitic volcanism

We report the first high-precision δ18O analyses of glass, δ18O of minerals, and trace element concentrations in glass and minerals for the 260–79 ka Central Plateau Member (CPM) rhyolites of Yellowstone, a >350 km3 cumulative volume of lavas erupted inside of 630 ka Lava Creek Tuff (LCT) caldera. The glass analyses of these crystal-poor rhyolites provide direct characterization of the melt and its evolution through time. The δ18Oglass values are low and mostly homogeneous (4.5 ± 0.14 ‰) within and in between lavas that erupted in four different temporal episodes during 200 ka of CPM volcanism with a slight shift to lower δ18O in the youngest episode (Pitchstone Plateau). These values are lower than Yellowstone basalts (5.7–6 ‰), LCT (5.5 ‰), pre-, and extracaldera rhyolites (~7–8 ‰), but higher than the earliest 550–450 ka post-LCT rhyolites (1–2 ‰). The glass δ18O value is coupled with new clinopyroxene analyses and previously reported zircon analyses to calculate oxygen isotope equilibration temperatures. Clinopyroxene records >900 °C near-liquidus temperatures, while zircon records temperatures <850 °C similar to zircon saturation temperature estimates. Trace element concentrations in the same glass analyzed for oxygen isotopes show evidence for temporal decreases in Ti, Sr, Ba, and Eu—related to Fe–Ti oxide and sanidine (±quartz) crystallization control, while other trace elements remain similar or are enriched through time. The slight temporal increase in glass Zr concentrations may reflect similar or higher temperature magmas (via zircon saturation) through time, while previosuly reported temperature decreases (e.g., Ti-in-quartz) might reflect changing Ti concentrations with progressive melt evolution. Multiple analyses of glass across single samples and in profiles across lava flow surfaces document trace element heterogeneity with compatible behavior of all analyzed elements except Rb, Nb, and U. These new data provide evidence for a three-stage geochemical evolution of these most recent Yellowstone rhyolites: (1) repeated batch melting events at the base of a homogenized low-δ18O intracaldera fill resulting in liquidus rhyolite melt and a refractory residue that sequesters feldspar-compatible elements over time. This melting may be triggered by conductive "hot plate" heating by basaltic magma intruding beneath the Yellowstone caldera resulting in contact rhyolitic melt that crystallizes early clinopyroxene and/or sanidine at high temperature. (2) Heterogeneity within individual samples and across flows reflects crystallization of these melts during preeruptive storage of magma at at lower, zircon-saturated temperatures. Compatible behavior and variations of most trace elements within individual lava flows are the result of sanidine, quartz, Fe–Ti oxide, zircon, and chevkinite crystallization at this stage. (3) Internal mixing immediately prior to and/or during eruption disrupts, these compositional gradients in each parental magma body that are preserved as melt domains distributed throughout the lava flows. These results based on the most recent and best-preserved volcanic products from the Yellowstone volcanic system provide new insight into the multiple stages required to generate highly fractionated hot spot and rift-related rhyolites. Our proposed model differs from previous interpretations that extreme Sr and Ba depletion result from long-term crystallization of a single magma body—instead we suggest that punctuated batch melting events generated a sanidine-rich refractory residue and a melt source region progressively depleted in Sr and Ba.

Design and integration of a spatio-temporal memory with emotional influences to categorize and recall the experiences of an autonomous mobile robot

Autonomous robots cohabiting with humans will have to achieve recurring tasks while adapting to the changing conditions of the world. A spatio-temporal memory categorizes the experiences of a robot to improve its ability to adapt to its environment. In this paper, we present a spatio-temporal (ST) memory model consisting of a cascade of two adaptive resonance theory (ART) networks: one to categorize spatial events and the other to extract temporal episodes from the robot's experiences. Artificial emotions are used to dynamically modulate learning and recall of the ART networks based on how the robot is able to carry its task, using a simple model of artificial emotions. Once an episode is recalled, future events can be predicted and used to influence the intentions of the robot. Evaluation of our ST model is done using an autonomous robotic platform that has to deliver objects to people within an office area. Results demonstrate that our model can memorize and recall the experiences of a robot, and that emotional episodes are recalled more often, allowing the robot to use its memory of past experiences early on when repeating a task.

Deuterium excess as a proxy for continental moisture recycling and plant transpiration

Abstract. Studying the evaporation process and its link to the atmospheric circulation is central for a better understanding of the feedbacks between the surface water components and the atmosphere. In this study, we use 5 months of deuterium excess (d) measurements at the hourly to daily timescale from a cavity ring-down laser spectrometer to characterise the evaporation source of low-level continental water vapour at the long-term hydrometeorological monitoring site Rietholzbach in northeastern Switzerland. To reconstruct the phase change history of the air masses in which we measure the d signature and to diagnose its area of surface evaporation we apply a Lagrangian moisture source diagnostic. With the help of a correlation analysis we investigate the strength of the relation between d measurements and the moisture source conditions. Temporal episodes with a duration of a few days of strong anticorrelation between d and relative humidity as well as temperature are identified. The role of plant transpiration, the large-scale advection of remotely evaporated moisture, the local boundary layer dynamics at the measurement site and recent precipitation at the site of evaporation are discussed as reasons for the existence of these modes of strong anticorrelation between d and moisture source conditions. We show that the importance of continental moisture recycling and the contribution of plant transpiration to the continental evaporation flux may be deduced from the d–relative humidity relation at the seasonal timescale as well as for individual events. The methodology and uncertainties associated with these estimates of the transpiration fraction of evapotranspiration are presented and the proposed novel framework is applied to individual events from our data set. Over the whole analysis period (August to December 2011) a transpiration fraction of the evapotranspiration flux over the continental part of the moisture source region of 62% is found albeit with a large event-to-event variability (0% to 89%) for continental Europe. During days of strong local moisture recycling a higher overall transpiration fraction of 76% (varying between 65% and 86%) is found. These estimates are affected by uncertainties in the assumptions involved in our method as well as by parameter uncertainties. An average uncertainty of 11% results from the strong dependency of the transpiration estimates on the choice of the non-equilibrium fractionation factor. Other uncertainty sources like the influence of boundary layer dynamics are probably large but more difficult to quantify. Nevertheless, such Lagrangian estimates of the transpiration part of continental evaporation could potentially be useful for the verification of model estimates of this important land–atmosphere coupling parameter.

Eye movements blink the attentional blink.

When presented with a sequence of visual stimuli in rapid succession, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1997). On the basis of a vast corpus of experiments, several cognitive theories suggest that the blink results from a discrete structuring of attention, sampling information from temporal episodes during which several items can access encoding process (Wyble, Bowman, & Nieuwenstein, 2009; Wyble, Potter, Bowman, & Nieuwenstein, 2011). The objective of this work is to explore the AB when multiple items are presented at the fovea during ocular movements. The authors reasoned that each fixation may cohesively form an episode and hence expected that the blink may vanish within a single fixation. In turn, they expected saccades to accentuate episodic borders and hence shorten the regime of interference when 2 targets are presented fovealy in successive fixations. Evidence is provided in favor of this hypothesis, showing that the blink vanishes when both targets are presented in the core of a single fixation (far from the saccadic boundaries) and that it recovers more rapidly in successive fixations. These studies support current views that episodes should have an effect on the AB and provide evidence that eye movements play an important role in the formation of episodes.

Attentional episodes in visual perception.

Is one's temporal perception of the world truly as seamless as it appears? This article presents a computationally motivated theory suggesting that visual attention samples information from temporal episodes (episodic simultaneous type/serial token model; Wyble, Bowman, & Nieuwenstein, 2009). Breaks between these episodes are punctuated by periods of suppressed attention, better known as the attentional blink (Raymond, Shapiro, & Arnell, 1992). We test predictions from this model and demonstrate that participants were able to report more letters from a sequence of 4 targets presented in a dense temporal cluster than from a sequence of 4 targets interleaved with nontargets. However, this superior report accuracy comes at a cost in impaired temporal order perception. Further experiments explore the dynamics of multiple episodes and the boundary conditions that trigger episodic breaks. Finally, we contrast the importance of attentional control, limited resources, and memory capacity constructs in the model.

A neural model of the temporal dynamics of figure–ground segregation in motion perception

How does the visual system manage to segment a visual scene into surfaces and objects and manage to attend to a target object? Based on psychological and physiological investigations, it has been proposed that the perceptual organization and segmentation of a scene is achieved by the processing at different levels of the visual cortical hierarchy. According to this, motion onset detection, motion-defined shape segregation, and target selection are accomplished by processes which bind together simple features into fragments of increasingly complex configurations at different levels in the processing hierarchy. As an alternative to this hierarchical processing hypothesis, it has been proposed that the processing stages for feature detection and segregation are reflected in different temporal episodes in the response patterns of individual neurons. Such temporal epochs have been observed in the activation pattern of neurons as low as in area V1. Here, we present a neural network model of motion detection, figure-ground segregation and attentive selection which explains these response patterns in an unifying framework. Based on known principles of functional architecture of the visual cortex, we propose that initial motion and motion boundaries are detected at different and hierarchically organized stages in the dorsal pathway. Visual shapes that are defined by boundaries, which were generated from juxtaposed opponent motions, are represented at different stages in the ventral pathway. Model areas in the different pathways interact through feedforward and modulating feedback, while mutual interactions enable the communication between motion and form representations. Selective attention is devoted to shape representations by sending modulating feedback signals from higher levels (working memory) to intermediate levels to enhance their responses. Areas in the motion and form pathway are coupled through top-down feedback with V1 cells at the bottom end of the hierarchy. We propose that the different temporal episodes in the response pattern of V1 cells, as recorded in recent experiments, reflect the strength of modulating feedback signals. This feedback results from the consolidated shape representations from coherent motion patterns and the attentive modulation of responses along the cortical hierarchy. The model makes testable predictions concerning the duration and delay of the temporal episodes of V1 cell responses as well as their response variations that were caused by modulating feedback signals.

A model of V1 for visual working memory using cortical and interlaminar feedback

Event Abstract Back to Event A model of V1 for visual working memory using cortical and interlaminar feedback Thorsten Hansen1* and Heiko Neumann2 1 Justus Liebig University, Department of General Psychology, Germany 2 University of Ulm, Institute of Neural Information Processing, Germany Early visual areas can store specific information about visual features held in working memory for many seconds in the absence of a physical stimulus (Harrison & Tong 2009, Nature 458 632-635). We have developed a model of V1 using recurrent long-range interaction that enhances coherent contours (Hansen & Neumann 2008, Journal of Vision 8(8):8 1-25) and robustly extracts corners and junctions points (Hansen & Neumann 2004, Neural Computation 16(5) 1013-1037). Here we extend this model by incorporating an orientation selective feedback signal from a higher cortical area. The feedback signal is nonlinearly compressed and multiplied with the feedforward signal. The compression increases the gain for decreasing input, such that the selection of the orientation to be memorized is realized by a selective decrease of feedback for this orientation. As a consequence, the model predicts that the overall activity in the network should decrease with the number of orientations to be memorized. Model simulations reveal that the feedback results in sustained activity of the orientation to be memorized over many recurrent cycles after stimulus removal. The pattern of activity is robust against an intervening, irrelevant orthogonal orientation shown after the orientation to be memorized. We suggest that the prolonged activation for sustained working memory in V1 shares similarities with the finding that different processing stages map onto different temporal episodes of V1 activation in figure-ground segregation (Roelfsema, Tolboom, & Khayat 2007, Neuron 56 785-792). Unlike previous approaches that have modeled working memory with a dedicated circuit, we show that a model of recurrent interactions in a sensory area such as V1 can be extended to memorize visual features by incorporating a feedback signal from a higher area. Conference: Bernstein Conference on Computational Neuroscience, Frankfurt am Main, Germany, 30 Sep - 2 Oct, 2009. Presentation Type: Poster Presentation Topic: Dynamical systems and recurrent networks Citation: Hansen T and Neumann H (2009). A model of V1 for visual working memory using cortical and interlaminar feedback. Front. Comput. Neurosci. Conference Abstract: Bernstein Conference on Computational Neuroscience. doi: 10.3389/conf.neuro.10.2009.14.055 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 26 Aug 2009; Published Online: 26 Aug 2009. * Correspondence: Thorsten Hansen, Justus Liebig University, Department of General Psychology, Giessen, Germany, thorsten.hansen@psychol.uni-giessen.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Thorsten Hansen Heiko Neumann Google Thorsten Hansen Heiko Neumann Google Scholar Thorsten Hansen Heiko Neumann PubMed Thorsten Hansen Heiko Neumann Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

MULTI VARIABLE EVENT DETECTION IN INTENSIVE CARE UNITS

: This paper presents a methodology to automatically detect specific medical events occurring on patients from ICU high frequency physiological variables. The physiological variables are transformed into a succession of temporal episodes (trend) and residual by an adaptive trend extraction method. Event models using temporal episodes from several variables are proposed. Results obtained on 70 hours of recordings from 23 adult patients hospitalised in ICU assess the capacity of the method to recognize events.

Historical population demography of red snapper (Lutjanus campechanus) from the northern Gulf of Mexico based on analysis of sequences of mitochondrial DNA

We evaluated stock structure and demographic (population) history of red snapper (Lutjanus campechanus) in the northern Gulf of Mexico (Gulf) via analysis of mitochondrial (mt)DNA sequences from 360 individuals sampled from four cohorts (year classes) at three localities across the northern Gulf. Exact tests of genetic homogeneity and analysis of molecular variance both among cohorts within localities and among localities were non-significant. Nested clade analysis provided evidence of different temporal episodes of both range expansion and restricted gene flow due to isolation by distance. A mismatch distribution of pairwise differences among mtDNA haplotypes and a maximum-likelihood coalescence analysis indicated a population expansion phase that dated to the Pleistocene and probably represents (re)colonization of the continental shelf following glacial retreat. The spatial distribution of red snapper in the northern Gulf appears to have a complex history that likely reflects glacial advance/retreat, habitat availability and suitability, and hydrology. Habitat availability/suitability and hydrology may partially restrict gene flow among present-day red snapper in the northern Gulf and give rise to a metapopulation structure with variable demographic connectivity. This type of population structure may be difficult to detect with commonly used, selectively neutral genetic markers.

On line extraction of temporal episodes from ICU high-frequency data: A visual support for signal interpretation

This paper presents a method to extract on line temporal episodes from high-frequency physiological parameters monitored in ICU, as a visual support for signal interpretation. Temporal episodes are expressions such as: "systolic blood pressure is steady at 120 mmHg from time t(0) until time t(1); it increases from 120 to 160 mmHg from time t(1) to time t(2) ...". Three words are used to describe the data evolution: {steady, increasing, decreasing}. The method deals with noisy data and missing values. It uses a segmentation algorithm that was developed previously and a classification of the segments into temporal patterns. The results obtained on simulated data are quite satisfactory. They show that the method is able to detect rapid variations as well as slow trends. Episodes extracted from real S(p)o(2) data recorded over a period of 44 h from 10 different adult patients are analysed. The visual representation of the temporal episodes is a powerful tool to help the physicians analyse in a glance the evolution in time of the variables monitored. It can help carer personnel to make quicker decisions in alarm situations.

AN INTELLIGENT ALARM SYSTEM BASED ON TEMPORAL EPISODES FOR INTENSIVE CARE UNITS

This paper presents an alarm system based on temporal episodes. A temporal episode is semi qualitative information that describes the signal trend. The system developed is a limit alarm system based on episodes extracted on line. It is able to recognize specific signal behaviours such as probe disconnection or steady state near the alarm limit threshold. The system is implemented to run on line and was tested on 36 hours of data recorded on adult patients hospitalized in Intensive Care Units. The alarm periods generated are compared to those raised by a classical limit alarm system. The conclusion is that 33% of the alarms raised by the classical system would be filtered, without any clinically relevant alarm missed.

Trends extraction and analysis for complex system monitoring and decision support

This paper presents an effective trend extraction procedure, based on a simple, yet powerful, representation. Its usefulness for complex system monitoring and decision support is illustrated by three examples. The method extracts semi-qualitative temporal episodes on-line, from any univariate time series. Three primitives are used to describe the episodes: { Increasing, Decreasing, Steady}. The method uses a segmentation algorithm, a classification of the segments into seven temporal shapes and a temporal aggregation of episodes. It acts on noisy data, without prefiltering. The first illustration is devoted to decision support in intensive care units. The signals contain information and noise at very different frequencies, and smoothing must not mask some interesting high-frequency data features. The second illustration is dedicated to a food industry process. On-line trends of key variables represent a very useful monitoring tool to control the end product quality despite high variations of raw materials at the input and a long delay. The last example concerns operator support and predictive maintenance. The results issued from a diagnostic module are complemented by the extrapolation of the key variable trends, which gives an idea of the time left to repair or reconfigure the process.

Current trends and future directions for the Canadian healthcare system

This paper outlines the structure of healthcare in Canada and describes trends in health expenditures. Particular attention is paid to trends in Canada's most populous province, Ontario. Three temporal episodes of health expenditure growth in Ontario are identified: 1980–91, a period of rapid growth; 1991–98, a period of restraint; and 1998‐present, a period of expenditure resurgence. Health policy initiatives designed to enhance the efficient, effective and equitable access to healthcare services are briefly reviewed.

Representation of process trends—Part I. A formal representation framework

A formal methodology capable of transforming time-records of process variables into meaningful and explicit descriptions of process trends in real-time is presented in this paper. The representation is based on the formal definition of “temporal episodes,” which provide descriptions of trends by constructing “histories of episodes” making explicitly all the important “domain landmark values” specified by the user as well as the “geometric landmark values” generic to trends. Model inaccuracies are confined by establishing specific measures of information lost in the descriptions and keeping them below those of the process models. Despite the simplicity of the representation primitives, it is shown that the representation can provide complete, correct, robust and very compact models for process trend histories. In contrast to pure qualitative descriptions, the new representation contains sufficient quantitative information to allow for powerful inferences of the trends of the unmeasure variables.