An embedded real-time red peach detection system based on an OV7670 camera, ARM Cortex-M4 processor and 3D Look-Up Tables

This work proposes the development of an embedded real-time fruit detection system for future automatic fruit harvesting. The proposed embedded system is based on an ARM Cortex-M4 (STM32F407VGT6) processor and an Omnivision OV7670 color camera. The future goal of this embedded vision system will be to control a robotized arm to automatically select and pick some fruit directly from the tree. The complete embedded system has been designed to be placed directly in the gripper tool of the future robotized harvesting arm. The embedded system will be able to perform real-time fruit detection and tracking by using a three-dimensional look-up-table (LUT) defined in the RGB color space and optimized for fruit picking. Additionally, two different methodologies for creating optimized 3D LUTs based on existing linear color models and fruit histograms were implemented in this work and compared for the case of red peaches. The resulting system is able to acquire general and zoomed orchard images and to update the relative tracking information of a red peach in the tree ten times per second.

Prospective motion correction of 3D echo-planar imaging data for functional MRI using optical tracking.

We evaluated the performance of an optical camera based prospective motion correction (PMC) system in improving the quality of 3D echo-planar imaging functional MRI data. An optical camera and external marker were used to dynamically track the head movement of subjects during fMRI scanning. PMC was performed by using the motion information to dynamically update the sequence's RF excitation and gradient waveforms such that the field-of-view was realigned to match the subject's head movement. Task-free fMRI experiments on five healthy volunteers followed a 2×2×3 factorial design with the following factors: PMC on or off; 3.0mm or 1.5mm isotropic resolution; and no, slow, or fast head movements. Visual and motor fMRI experiments were additionally performed on one of the volunteers at 1.5mm resolution comparing PMC on vs PMC off for no and slow head movements. Metrics were developed to quantify the amount of motion as it occurred relative to k-space data acquisition. The motion quantification metric collapsed the very rich camera tracking data into one scalar value for each image volume that was strongly predictive of motion-induced artifacts. The PMC system did not introduce extraneous artifacts for the no motion conditions and improved the time series temporal signal-to-noise by 30% to 40% for all combinations of low/high resolution and slow/fast head movement relative to the standard acquisition with no prospective correction. The numbers of activated voxels (p<0.001, uncorrected) in both task-based experiments were comparable for the no motion cases and increased by 78% and 330%, respectively, for PMC on versus PMC off in the slow motion cases. The PMC system is a robust solution to decrease the motion sensitivity of multi-shot 3D EPI sequences and thereby overcome one of the main roadblocks to their widespread use in fMRI studies.

Why do university graduates regret their study program? A comparison between Spain and the Netherlands

[cat] En aquest article investiguem els factors que porten a universitaris espanyols i holandesos a lamentar els estudis cursats. Espanya i Holanda tenen un sistema educatiu molt diferent en termes de la rigidesa de l’educació secundària i el vincle entre l’educació i el mercat laboral. Comparant Espanya i Holanda ens permet aprendre sobre les conseqüències de dos sistemes educatius molt diferenciats a la probabilitat de lamentar els estudis cursats. Basant-nos en la literatura psicològica sobre l’arrepentiment/lamentació, derivem unes hipòtesis de partida que contrastem empíricament. Els resultats mostren que tant la rigidesa de l’educació secundària com el desajustament entre educació i ocupació són factors importants per explicar la lamentació dels estudis universitaris cursats. L’article conclou amb recomenacions sobre el sistema educatiu universitari.

Why do university graduates regret their study program? A comparison between Spain and the Netherlands

[cat] En aquest article investiguem els factors que porten a universitaris espanyols i holandesos a lamentar els estudis cursats. Espanya i Holanda tenen un sistema educatiu molt diferent en termes de la rigidesa de l’educació secundària i el vincle entre l’educació i el mercat laboral. Comparant Espanya i Holanda ens permet aprendre sobre les conseqüències de dos sistemes educatius molt diferenciats a la probabilitat de lamentar els estudis cursats. Basant-nos en la literatura psicològica sobre l’arrepentiment/lamentació, derivem unes hipòtesis de partida que contrastem empíricament. Els resultats mostren que tant la rigidesa de l’educació secundària com el desajustament entre educació i ocupació són factors importants per explicar la lamentació dels estudis universitaris cursats. L’article conclou amb recomenacions sobre el sistema educatiu universitari.

Activity patterns and foraging behaviour of Audouin's gulls at the Ebro Delta, NW Mediterranean.

Twenty Audouin´s gulls, Larus audouinii, breeding in the Ebro Delta (NW Mediterranean) were radio-tracked in 1998 to study their foraging behaviour and activity patterns. Some detrimental effects of tagging on the breeding success of the birds were detected, especially when both members of the pair were tagged. The results were actually constrained by the low number of locations due to natural breeding failure and failure in tag emission, as well as the adverse effect of tagging. However, through a combination of aircraft surveys at sea and a fixed station for automatic tracking of the presence of the birds at the colony, novel individual-based information of home ranges and activity patterns was obtained. Trawler fishing activity seemed to influence both the foraging range and habitat use: while trawlers operated, gulls overlapped their fishing grounds with vessels, probably to scavenge on discards. Very few locations were obtained during a trawling moratorium period, although they were all recorded in coastal bays and terrestrial habitats. During the trawling activity period, gulls ranged over a minimum convex polygon area of 2900 km2. Gulls were tracked up to 40 km from the colony, but some individuals were observed beyond 150 km while still breeding. Arrivals and departures from the colony were in accordance with the trawling timetable. However, most birds also showed some nocturnal foraging activity, probably linked to active fishing of clupeoids (following diel migrations) or to the exploitation of purse-seine fishing activity. Foraging trips lasted on average 15 hours: males performed significantly shorter trips than females, which spent more time outside the colony. The proportion of nocturnal time involved in the foraging trips was the same for males and females, but whilst all males initiated their trips both during the day and at night, some females only initiated their trips during the day. Hatching success was found to be related to foraging effort by males. Gulls spent on average ca. 38% of their time budget outside the nesting territory, representing the time devoted mainly to flying, foraging and other activities.

Entrepreneurial skills and over-education five years later. A comparison between Spain and the Netherlands

[cat] El fenòmen de la sobre-educació és freqüent i persistent a molts països. En aquest article estudiem el paper de les habilitats emprenedores en evitar la sobre-educació a la primera feina, i en sortir d’una situació de sobre-educació cinc anys després. Comparem els resultats d’Espanya i Holanda, dos països que difereixen en el seu sistema educatiu i mercat de treball. Els resultats mostren que les habilitats emprenedores ajuden a evitar i/o sortir de la sobre-educació només a Espanya, on el sistema educatiu és més flexible i menys vinculat amb el mercat de treball. En general, els nostres resultats recolzen les polítiques que promocionen el desenvolupament d’habilitats emprenedores al sistema educatiu espanyol.

Entrepreneurial skills and over-education five years later. A comparison between Spain and the Netherlands

[cat] El fenòmen de la sobre-educació és freqüent i persistent a molts països. En aquest article estudiem el paper de les habilitats emprenedores en evitar la sobre-educació a la primera feina, i en sortir d’una situació de sobre-educació cinc anys després. Comparem els resultats d’Espanya i Holanda, dos països que difereixen en el seu sistema educatiu i mercat de treball. Els resultats mostren que les habilitats emprenedores ajuden a evitar i/o sortir de la sobre-educació només a Espanya, on el sistema educatiu és més flexible i menys vinculat amb el mercat de treball. En general, els nostres resultats recolzen les polítiques que promocionen el desenvolupament d’habilitats emprenedores al sistema educatiu espanyol.

Market Index Biases and Minimum Risk Indices

Markets, in the real world, are not efficient zero-sum games where hypotheses of the CAPM are fulfilled. Then, it is easy to conclude the market portfolio is not located on Markowitz"s efficient frontier, and passive investments (and indexing) are not optimal but biased. In this paper, we define and analyze biases suffered by passive investors: the sample, construction, efficiency and active biases and tracking error are presented. We propose Minimum Risk Indices (MRI) as an alternative to deal with to market index biases, and to provide investors with portfolios closer to the efficient frontier, that is, more optimal investment possibilities. MRI (using a Parametric Value-at-Risk Minimization approach) are calculated for three stock markets achieving interesting results. Our indices are less risky and more profitable than current Market Indices in the Argentinean and Spanish markets, facing that way the Efficient Market Hypothesis. Two innovations must be outlined: an error dimension has been included in the backtesting and the Sharpe"s Ratio has been used to select the"best" MRI

Wireless Applications Evaluation and Development Process: Case -Paper Industry Logistics

Sähköisen liiketoiminnan ja mobiliteetin konvergenssi yhdessä teknologisen innovaation kiihtyvän vauhdin kanssa ovat saaneet aikaan kiinnostusta langattomia liiketoimintaratkaisuja kohtaan. Tämän diplomityön tavoitteena oli tutkia sähköisen liiketoiminnan langattomien sovellusten arviointi- ja kehitysprosessia. Työ keskittyy tarkastelemaan paperiteollisuuden toimitusketjun langatonta seurantaa. Tutkimuksessa esitetään langattoman sähköisen liiketoiminnan määritelmä, kuvaillaan langattomuuden eri sovellusalueita ja sovellusten arviointi- ja kehitysprosessin strategisia sekä teknologisia ulottuvuuksia. Työ luo viitekehyksen, jonka avulla tarkastella langattomien teknologioiden merkitystä logistiikassa. Tutkimuksen merkittävin tulos on prosessimalli sovellusten arvioimiseksi ja kehittämiseksi. Mallilla kehitetty langaton sovellus osoittautui tarkastelussa hyödylliseksi toimitusketjun hallinnassa.

Improving Pitch Tracking Performance in Hard Noise Conditions by a Preprocessing Based on Mathematical Morphology

In this paper we show how a nonlinear preprocessing of speech signal -with high noise- based on morphological filters improves the performance of robust algorithms for pitch tracking (RAPT). This result happens for a very simple morphological filter. More sophisticated ones could even improve such results. Mathematical morphology is widely used in image processing and has a great amount of applications. Almost all its formulations derived in the two-dimensional framework are easily reformulated to be adapted to one-dimensional context

Accuracy and Precision of Head Motion Information in Multi-Channel Free Induction Decay Navigators for Magnetic Resonance Imaging.

Free induction decay (FID) navigators were found to qualitatively detect rigid-body head movements, yet it is unknown to what extent they can provide quantitative motion estimates. Here, we acquired FID navigators at different sampling rates and simultaneously measured head movements using a highly accurate optical motion tracking system. This strategy allowed us to estimate the accuracy and precision of FID navigators for quantification of rigid-body head movements. Five subjects were scanned with a 32-channel head coil array on a clinical 3T MR scanner during several resting and guided head movement periods. For each subject we trained a linear regression model based on FID navigator and optical motion tracking signals. FID-based motion model accuracy and precision was evaluated using cross-validation. FID-based prediction of rigid-body head motion was found to be with a mean translational and rotational error of 0.14±0.21 mm and 0.08±0.13(°) , respectively. Robust model training with sub-millimeter and sub-degree accuracy could be achieved using 100 data points with motion magnitudes of ±2 mm and ±1(°) for translation and rotation. The obtained linear models appeared to be subject-specific as inter-subject application of a "universal" FID-based motion model resulted in poor prediction accuracy. The results show that substantial rigid-body motion information is encoded in FID navigator signal time courses. Although, the applied method currently requires the simultaneous acquisition of FID signals and optical tracking data, the findings suggest that multi-channel FID navigators have a potential to complement existing tracking technologies for accurate rigid-body motion detection and correction in MRI.

Eye-tracking of nodule detection in lung CT volumetric data.

PURPOSE: Signal detection on 3D medical images depends on many factors, such as foveal and peripheral vision, the type of signal, and background complexity, and the speed at which the frames are displayed. In this paper, the authors focus on the speed with which radiologists and naïve observers search through medical images. Prior to the study, the authors asked the radiologists to estimate the speed at which they scrolled through CT sets. They gave a subjective estimate of 5 frames per second (fps). The aim of this paper is to measure and analyze the speed with which humans scroll through image stacks, showing a method to visually display the behavior of observers as the search is made as well as measuring the accuracy of the decisions. This information will be useful in the development of model observers, mathematical algorithms that can be used to evaluate diagnostic imaging systems. METHODS: The authors performed a series of 3D 4-alternative forced-choice lung nodule detection tasks on volumetric stacks of chest CT images iteratively reconstructed in lung algorithm. The strategy used by three radiologists and three naïve observers was assessed using an eye-tracker in order to establish where their gaze was fixed during the experiment and to verify that when a decision was made, a correct answer was not due only to chance. In a first set of experiments, the observers were restricted to read the images at three fixed speeds of image scrolling and were allowed to see each alternative once. In the second set of experiments, the subjects were allowed to scroll through the image stacks at will with no time or gaze limits. In both static-speed and free-scrolling conditions, the four image stacks were displayed simultaneously. All trials were shown at two different image contrasts. RESULTS: The authors were able to determine a histogram of scrolling speeds in frames per second. The scrolling speed of the naïve observers and the radiologists at the moment the signal was detected was measured at 25-30 fps. For the task chosen, the performance of the observers was not affected by the contrast or experience of the observer. However, the naïve observers exhibited a different pattern of scrolling than the radiologists, which included a tendency toward higher number of direction changes and number of slices viewed. CONCLUSIONS: The authors have determined a distribution of speeds for volumetric detection tasks. The speed at detection was higher than that subjectively estimated by the radiologists before the experiment. The speed information that was measured will be useful in the development of 3D model observers, especially anthropomorphic model observers which try to mimic human behavior.

Fifty years after Ehrlich and Raven, is there support for plant-insect coevolution as a major driver of species diversification?

Since Ehrlich & Raven's seminal paper 50 years ago, coevolution has been seen as a major driver of species diversification. Here, we review classical and more recent case studies on the coevolution of plants and associated insects, to examine whether the coevolutionary component holds as an explanation of their current diversity. We discuss the main dogmas in coevolution and argue that coevolutionary processes should not be considered as major drivers of diversification in plants and insects. Instead, we suggest that coevolution essentially occurs through relatively short 'interludes', making the pattern difficult to detect. We also criticize the use of comparative phylogenetics to investigate coevolutionary processes, as coevolution may not necessarily produce congruent phylogenies among interacting lineages and, in turn, other processes may produce patterns of codivergence. Finally, we propose new lines of investigation for future research.

A Novel Approach to Major Surgery: Tracking Its Pathophysiologic Footprints.

BACKGROUND: To study the 'metabolic profile' of different surgical procedures and correlate it with pertinent surgical details and postoperative complications. METHODS: We conducted a prospective pilot study of 70 patients, ten for each of the seven following groups: (1) laparoscopic cholecystectomy, (2) incisional hernia repair, (3) laparoscopic and (4) open colon surgery, (5) upper gastrointestinal, (6) hepatic, and (7) pancreatic resections. Biochemical assessment included white blood cell count (WBC), C-reactive protein (CRP), glucose, triglycerides (TG), albumin (Alb), and pre-albumin (Pre-Alb), from the day before surgery until 5 days thereafter. Biological markers were compared for major versus minor surgery groups, which were defined on a clinical basis. Univariable analysis was used to identify risk factors for postoperative complications and p < 0.05 was the significance threshold. RESULTS: Common findings in all surgery groups were the acute inflammatory response (↑: WBC, CRP, ↓: TG, Alb, pre-Alb). Using cut-off values of 240 min operative (OR) time and 300 ml estimated blood loss (EBL), laparoscopic cholecystectomy, incisional hernia repair, and laparoscopic colectomy could be distinguished from open colectomy, upper gastrointestinal, liver, and pancreas resections. In a biochemical level, increased CRP and reduced postoperative Alb levels were highly discriminative of all types of 'major surgery.' Significant risk factors for postoperative complications were age, male gender, malignancy, longer OR time, higher blood loss, high CRP, and low Alb levels. CONCLUSIONS: Biochemically, CRP and Alb levels can help quantify the magnitude of the surgical trauma, which is correlated with adverse outcomes.

Reliable misrepresentation and teleosemantics

Mendelovici (forthcoming) has recently argued that (1) tracking theories of mental representation (including teleosemantics) are incompatible with the possibility of reliable misrepresentation and that (2) this is an important difficulty for them. Furthermore, she argues that this problem commits teleosemantics to an unjustified a priori rejection of color eliminativism. In this paper I argue that (1) teleosemantics can accommodate most cases of reliable misrepresentation, (2) those cases the theory fails to account for are not objectionable and (3) teleosemantics is not committed to any problematic view on the color realism-antirealism debate