julio eduardo gutierrez

ABSTRACT Takagi-Sugeno fuzzy controllers are today one of the most promising technique to describe input-output relations of nonlinear systems using fuzzy rules. This chapter presents an extension of this modelling technique mainly based on the use of global fuzzy parameters and convolution operators to specify different uncertainties of a system: imprecision of inputs, vagueness of antecedent linguistic labels and smoothness requirements of outputs. The presented approach provides an efficient method to specify and implement an extended zero order product-sum Takagi-Sugeno controller with fuzzy inputs, antecedent terms fuzzy partition with an additional uniform vagueness, and singletons outputs with an additional output filter. It introduces a similarity transformation that greatly simplifies the involved computation. The most relevant feature of this approach is a global transformation of imprecision of inputs, uniform vagueness of antecedent terms and smoothness requirements of outputs into a single convolution transform applied to the corresponding antecedent terms partition. The kernels of the fuzzification transforms used are even B-spline functions. Some practical considerations and examples are also given.

Native vegetation and temporal variation of its productivity in the Elqui Province. Diverse geographical and climatic factors determine a high plant heterogeneity in the Elqui Province. Among several, there is a steep altitudinal gradient (0 to 6,000 masl in a distance of 150 km), a mountain relief, a coastal desert climate, and climatic oscillation such as ENSO. These factors generate spatial and temporal gradients of temperature, water availability, radiation, among others, which effect changes in species composition and life forms. Most of the land is covered with low shrublands accompanied in some cases by succulents. Agriculture is concentrated in the valley bottoms and represents 2.1% of the surface land. Native plant productivity increases in the rainy years associated to ENSO events. This province has a high native biodiversity, but about one third of the plant species have conservation problems. In 2001 six priority sites for conserving the plant diversity were proposed; ho...

Background/Question/Methods The need to understand global change and biodiversity loss has promoted ecological studies on broad spatial and temporal scales. Thus, long-term ecological research (LTER) has served as a successful organizing framework to guide research agendas designed to address meaningful ecological phenomena and questions at the scales of decades or whole ecosystems. The international LTER network has sites on every continent, allowing for global comparisons. Nevertheless, LTER sites are predominantly located at high latitudes in the northern hemisphere and there is a lack of formalized long-term research sites in southern South America. This is the only continental area besides Antarctica reaching beyond 47 S. The Institute of Ecology and Biodiversity (Chile) has begun to fill this gap by linking work at three research sites (Fray Jorge Forest National Park – 33° S, Senda Darwin Biological Station – 43° S, and Omora Ethnobotanical Park – 55° S) to establish the firs...

Background/Question/Methods Chile’s growing economy is largely dependent on natural resource use, including ore mining, hydroelectric power generation, crop production, exotic species forestry, and salmon farming. However, environmental impacts of these activities, accompanied by climate change, are generating fast-paced deterioration and loss of ecosystem services and biodiversity, in the absence of long-term sustainability plans. To monitor, mitigate, and prevent such impacts, long-term records of key ecological indicators and processes are necessary for representative Chilean ecosystems. The Chilean Long-Term Socio-ecological Research (LTSER) Network was created in 2008 with the aim of consolidating long-term research in selected ecosystems of southern South America, using an approach that integrates the social, ethical, and ecological domains of environmental change from local to global scales. Our present challenge is to put in place an institutional framework that promotes sci...

Contenido: Breve referencia de la evolución histórica de la lógica; La lógica como teoría de la inferencia; Clases de proposiciones; Las inferencias; Principales tautologías; Diagramas de Venn; Análisis de las inferencias; La conversión; La contraposición; El silogismo.

We examined live-trap data of 4 small mammal species for evidence of behavioral responses to predator and/or competitor exclusions in a semiarid thorn scrub community in north-central Chile. The species included an herbivorous hystricognath rodent, Octodon degus, a granivorous/herbivorous sigmodontine rodent, Phyllotis darwini, and 2 omnivorous/insectivorous sigmodontines, Abrothrix olivaceus and Abrothrix longipilis. Significant numerical effects of predation on O. degus were present during the study; although none were detected on P. darwini, previous analyses showed significant but small magnitude effects of predation. Both species had significant effects of predation on survival. We examined effects of biotic interactions on mean distance between successive captures (MDBSC) for consecutive 6-month seasons during a 36- month period during and following an El Niño (ENSO) event in 1991-1994. Time and density were included with predation and competition in 4-way analyses of variance...

Background/Question/Methods The separate effects of shrubs, herbivores and winter rainfall on ephemeral communities have been studied for decades in a worldwide range of arid/semi-arid ecosystems. These three abiotic/biotic factors appear to be determining elements for the assembly of ephemeral herbaceous species in xeric environments. However, little attention has been directed to the study of ecological constraints that each exerts when they act simultaneously in natural environments. We explored the interaction of these three factors in the assembly pattern of winter ephemeral communities in semi-arid coastal Chile (north-central Chile, IV Region). Multivariate analysis of ordination, cluster, and GLM statistics were used to test the environmental effects of the main gradients of ephemeral community heterogeneity. Results/Conclusions Shrub canopy (mainly that of Porlieria chilensis) was the most important factor for ephemeral assemblages through creation of a local patch mosaic o...

Background/Question/Methods . In unpredictable and temporally variable environments, evolution should select for life-history strategies to survive challenging times and to capitalize on times of resource availability. In semiarid environments, variability in the frequency and strength of rainfall pulses controls annual plant recruitment. Under such circumstances bet-hedging strategies favor strategies that spread the risk of mortality and favor long-term reproductive success. Evolutionarily and geographically unrelated species could develop similar strategies, in which case the processes that favor persistence and recruitment of native species could also promote the establishment and persistence of exotic species. At our long-term site in semiarid Chile we assessed whether native and exotic annual species expressed similar or contrasting bet-hedging traits, and if such strategies promoted coexistence under the highly variable precipitation regime driven by El Niño Southern Oscillat...

Background/Question/Methods In 1989 we initiated an LTER in Quebrada de las Vacas, Bosque Fray Jorge National Park, in north-central Chile: we focused on the following: 1) what is the role of biotic interactions such as vertebrate predation, interspecific competition, and herbivory on components of the semiarid community here?; 2) how do abiotic events such as aperiodic ENSOs alter the role of such interactions?; and 3) What are the individual effects of small mammals vs. lagomorphs on the plant community? To address the last question we have maintained five treatments (4 - 0.56 ha replicates ea.) since 2008. These include control plots (C) with open access to all small mammals and predators, and four biotic treatments: i.e., predator exclusion plots with access to all small mammals (-P); exclusion of small mammals (-SM); exclusion of lagomorphs (rabbits and hares) (-L); and exclusion of small mammals + lagomorphs (–SM-L). We inventoried plant cover of ephemeral plants (annual and g...

Background/Question/Methods In the 1980’s, much attention was focused on the role of biotic interactions as regulatory factors in communities. Preliminary data on small mammals at a semiarid site in north-central Chile suggested the importance of top-down biotic interactions including predation and interspecific competition. In 1989, we initiated a large-scale ecological experiment in a thorn scrub community using a reductionist approach. Fenced exclosures were installed to selectively exclude vertebrate predators (raptors and foxes), and putative competitors/herbivores (a medium-sized rodent, the Chilean degu) from replicated 0.56 ha grids. Small mammals have been inventoried monthly using mark-recapture techniques. Additional metrics collected include predator activity and diets, perennial shrub and ephemeral cover, and soil seed densities. Over time, we expanded our work with food addition experiments in 1996-1999, and monitoring of other organismal groups including lizards, inse...

Since 1989, we have conducted a large-scale ecological experiment in semiarid thorn scrub of a national park in north-central Chile. Initially, we focused on the role of biotic interactions including predation, interspecific competition, and herbivory in small mammal and plant components of the community. We utilized a reductionist approach with replicated 0.56 ha fenced grids that selectively excluded vertebrate predators and/or larger small mammal herbivores such as the degu, Octodon degus. Although we detected small transitory effects of predator exclusions on degu survival and numbers, other species failed to show responses. Similarly, interspecific competition (i.e., degus with other small mammals) had no detectable numerical effects (although some behavioral responses occurred), and degu-exclusions had relatively small effects on various plant components. Modeling approaches indicate that abiotic factors play a determining role in the dynamics of principal small mammal species...

Background/Question/Methods In 1989, we initiated a large-scale ecological experiment on the role of biotic interactions –including interactions among predators, small herbivores and plants- as regulatory factors of a thorn scrub community in north-central Chile. Since then we have monitored the seasonal perennial cover and phenology of the main shrub species (principally Adesmia bedwellii, Porlieria chilensis and Proustia cuneifolia), as well as their functional characteristics. Cover was monitored using permanent line transects and point-intercept techniques on replicated 0.56 ha fenced exclosures with two different treatments; exclusion of small rodent herbivores and control plots. Since 2003 we have monitored monthly phenology of three individuals of the three dominant shrub species, and tallied vegetative buds, new leaves, flower buds, flowers or fruits on four stems per shrub each facing one of the four cardinal directions. Results/Conclusions Woody vegetation is homogeneous b...

This paper presents a new fuzzy motion adaptive video deinterlacer that is adaptive at pixel and frame level. It is mainly based on a decomposition of the corresponding fuzzy motion detector into two main modules: a linear spatio-temporal low-pass filter described by two separable 1D FIR filters and two fuzzy modules described by saturation functions. Moreover, the involved saturation parameters are on-line adjusted taking into account the motion quantity of each frame. Experimental results with several video benchmarks demonstrate the robustness and high-quality reconstruction of the presented algorithm.

ABSTRACT Takagi-Sugeno fuzzy controllers are today one of the most promising technique to describe input-output relations of nonlinear systems using fuzzy rules. This chapter presents an extension of this modelling technique mainly based on the use of global fuzzy parameters and convolution operators to specify different uncertainties of a system: imprecision of inputs, vagueness of antecedent linguistic labels and smoothness requirements of outputs. The presented approach provides an efficient method to specify and implement an extended zero order product-sum Takagi-Sugeno controller with fuzzy inputs, antecedent terms fuzzy partition with an additional uniform vagueness, and singletons outputs with an additional output filter. It introduces a similarity transformation that greatly simplifies the involved computation. The most relevant feature of this approach is a global transformation of imprecision of inputs, uniform vagueness of antecedent terms and smoothness requirements of outputs into a single convolution transform applied to the corresponding antecedent terms partition. The kernels of the fuzzification transforms used are even B-spline functions. Some practical considerations and examples are also given.

ABSTRACT First-order Takagi-Sugeno models are mainly based on the interpolation between several local affine functions usually defined on trapezoidal fuzzy partitions. The standard computational model presents some shape-failures: the approximation does not preserve the positivity, monotony or convexity of the data that belong to the corresponding antecedent term cores. Moreover the standard output does not have a continuous derivative. This paper presents an improved model that primarily transforms the original first-order trapezoidal TS system into an equivalent zero-order triangular TS one. Furthermore, for each univariate transition region: two equidistant triangular labels are added, one at each end of the corresponding interval, to capture the information of derivatives of the affine functions. Finally in each transition region, a local even box filter is applied to the corresponding four triangular labels in order to obtain a local uniform quadratic B-spline partition. This transform preserves the original affine functions in the reduced cores of the original fuzzy partition and converts the intermediate C 0 piecewise linear-multilinear output function into a C 1 piecewise linear-multiquadratic one.

Abstract. This paper proposes an eclectic approach for the efficient computation of fiizzy rules based on fuzzy logic and signal processing techniques. The rules {Rr} of the MISO zero-order Takagi-Sugeno fuzzy system considered, are given in the form ofR/. If X/ is A ,j and ... and ...

First-order Takagi-Sugeno (TS) fuzzy systems are characterized by a multivariate fuzzy partition in the operating domain and a local affine function within each fuzzy region. This fuzzy inference method presents some undesirable properties in the regions where the membership functions of the antecedent fuzzy partitions overlap. The output function of a SISO affine TS system is in general a non-convex

Fuzzy logic is now widely accepted as a formal tool for describing control or decision-making processes that are based on incomplete, vague or uncertain information. This paper presents a new approach for the description and efficient computation of fuzzy rules based ...

This paper details the study of systolic architectures for fuzzy rules processing made at the Hardware and Advanced Control Laboratory - INTA. The theoretical basis of these architectures is described and analysed. Likewise, the resultant schematics are simulated using a hardware description language (VHDL) with standard cells from ES2. This gives us a very accurate assessment of their real performance. In this way we can detect the inherent shortcomings in this class of systems and we outline several ways of overcoming then.