Eigenspaces of Panoramic Images for Mobile Robot Localization

Appearance--based visual learning and recognition techniques that are based on models derived from a learning set of 2D images are being widely used in computer vision applications. In robotics, they have received most attention in visual servoing and navigation. In this thesis we discuss a framework for visual self--localization of mobile robots using a parametric model built from panoramic snapshots of the environment. Particularly, we propose solutions to the problems related to robustness against occlusions, illumination and invariance to the rotation of the sensor. Our principal contribution is the ``eigenspace of spinning--images'', i.e., a model of environment which successfully exploits some of the specific properties of panoramic images in order to efficiently calculate the optimal subspace in terms of Principal Components Analysis (PCA) of a set of training snapshots without actually decomposing the covariance matrix. By integrating a robust recover--and--select algorithm for the computation of image parameters we achieve reliability even in the case when the input images are partly occluded or noisy. Further, by applying a bank of gradient filters, we achieve a significant level of insensitivity to changes in the illumination of the environment. In this way, the robot is capable of localizing itself in realistic environments

Muhlenbergia schreberi J. F. Gmel (Poaceae), a new naturalized species in Croatia

Muhlenbergia schreberi, nimblewill, is a widespread North American perennial grass species, slowly spreading in European countries, where it has been recorded in Spain, Switzerland, Italy, and Slovenia. In addition, a well naturalized population was discovered in Opatija (Northwestern Croatia, Croatian Littoral) in 2011 as described herein. It has been recognized as a persistent weed in some North American states, and in the last few decades its secondary European distribution range has been slowly increasing. Thus most probably it will also spread in Croatia and become classified as invasive

Assessing the Effectiveness of Student Oriented Learning Outlines (SOLOs) In an Equine Classroom

This study determined if the use of the student oriented learning outline (SOLO) in a University of Arkansas equine production classroom had a positive influence in three areas: mastery of material taught, retention of material taught and voluntary positive student behaviors related to the use of course material. Thirty-one students who were enrolled in 2012 were in the non-SOLO group (control), and 25 students who were enrolled in 2013 were the SOLO group (treatment). Three separate units were taught to the treatment and control groups with only one difference: the treatment group was given a SOLO one week in advance of three equine production labs. Lab exam scores on three units taught with and without SOLOs were compared utilizing Analysis of Covariance (ANCOVA). ANCOVA was used to statistically control for any effects due to differences in high school grade point averages of participants. On two unit exams, the SOLO group significantly outperformed the non-SOLO group. On the third unit exam, the difference between the SOLO group and non-SOLO group was not statistically significant. When students anonymously responded to statements concerning SOLOs, their perceptions were overwhelmingly positive, underscoring the fact that the students found the SOLOs beneficial in preparing for exams and a useful guide for what should be learned. Positive affective indicators of voluntary student behavior were exhibited in each of the three SOLO labs; this demonstrated that students not only gained knowledge and skill but also continued to voluntarily use the knowledge or demonstrate the skill, because they believed it to be worthwhile

Novosti iz adventivne flore Slovenske Istre

V članku je predstavljenih nekaj novih nahajališč adventivnih vrst v Slovenski Istri. Najverjetneje prehodno pojavljanje na južni meji areala imajo vrste Dasypyrum villosum, Hedysarum coronarium in Piptatherum miliaceum s po enim novoodkritim nahajališčem, medtem ko so najverjetneje z vrtov ušle Iris foetidissima, Periploca graeca in Soleirolia soleirolii, prvi dve s po enim in slednja z več novimi nahajališči. Hedysarum coronarium in Periploca graeca sta bili prvič zabeleženi v flori SlovenijeArticle briefly discusses the occurrence of 6 adventitious species in the flora of Slovenian part of Istria. Dasypyrum villosum, Hedysarum coronarium and Piptatherum miliaceum are most probably recorded as casuals on the northern border of their native distribution range, each in one new locality. On the other hand, Iris foetidissima, Periploca graeca and Soleirolia soleirolii escaped from cultivation and established in one to more localities. Hedysarum coronarium and Periploca graeca were recorded for the first time in the flora of Sloveni

Epilobium ciliatum Raf., a new plant invader in Slovenia and Croatia

The North American invasive species Epilobium ciliatum Raf. was recently recorded for the first time in Slovenia and Croatia. The most reliable character with which to distinguish E. ciliatum from all native European Epilobium species is the presence of conspicuous longitudinal white stripes on the seed testa. If seeds are not available, E. ciliatum may easily be misidentified as E. roseum. With fieldwork and revision of herbarium material we ascertained that the invasion towards the territory discussed came from the north, which is in agreement with the north west to south east direction of the spread in Europe. At least in Eastern Slovenia E. ciliatum has already become an important member of ruderal plant communities. Rapid spreading and naturalization as in the case of E. ciliatum can give rise to concern that it will replace some indigenous species with a similar ecology or hybridise and so by introgression cause »genetic« pollution of native relatives’ populations. Further spread to the south and east is expected

Alien water lettuce (Pistia stratiotes L.) outcompeted native macrophytes and altered the ecological conditions of a Sava oxbow lake (SE Slovenia)

Introduction of an invasive alien macrophyte water lettuce (Pistia stratiotes L.) radically changed the oxbow lake in Prilipe (SE Slovenia) which has thermal springs that enables the winter survival of this tropical invader. About 10 years after the first record of P. stratiotes, the number, abundance and biomass of indigenous and non-indigenous macrophytes as well as different abiotic parameters were measured. In that period, colonized sections (~94% of the oxbow lake) were completely covered with water lettuce, and the only reservoirs of indigenous macrophyte species were the non-colonized areas (6%). Research in 2011 found only a third of the previously recorded indigenous macrophytes, but then only in small section without P. stratiotes. Three of the species that disappeared were on the Red data list. In the colonized section a higher biomass was observed than in the non-colonized section because of high abundance of water lettuce which remained the only macrophyte. Due to the presence of P. stratiotes, the intensity of light penetrating into the depth and water circulation were reduced, as was the oxygen saturation of the water. In addition to the well documented vegetative propagation of P. stratiotes, a well-established and viable seed bank has been detected in the lake sediment and after winter floods also on lake banks. In the future, special attention should be given to the thermal water ecosystems in temperate climates since they can serve as stepping stones and recruitment centres for the establishment and spread of (sub-)tropical invasive species. Facing predicted climate change such local populations of invasive species can act as stepping stones for further dispersal

Myosotis refracta Boiss. (Boraginaceae), an unexpected forget-me-not in the Slovene flora

Myosotis refracta Boiss. is reported as a new and unexpected finding for the Slovene flora. The species was found in three collections stored in the Herbarium LJU from south-east Slovenia, in the Kolpa river valley bordering Croatia. All plants thrived under overhanging dolomite rocks. On account of an earlier misidentification, the respective plant community had been described as the association Arabido alpinae- Myosotidetum strictae Accetto 2008, which is here corrected to Arabido alpinae-Myosotidetum refractae Accetto 2008 corr. Strgulc Krajšek, Accetto & Jogan 2016. Myosotis refracta has a disjunct Mediterranean southwest Asian distribution. The reported new localities extend its known range more than 500 km in north-west direction, from its nearest known occurrences on the southern Balkan peninsula

Rumex thyrsiflorus Fingerh., nova biljna vrsta za floru Hrvatske

Rumex thyrsiflorus has been recorded for the first time in the territory of Croatia. Several localities have been found around Varaždin (N Croatia). Its occurrence in this region can be explained by the expansion of its area of distribution from the central Europe towards the south. Superficially it is quite similar to R. acetosa from which it can be easily distinguished by its longer tap-root, narrower and longer leaf blades and denser inflorescence.Rumex thyrsiflorus has been recorded for the first time in the territory of Croatia. Several localities have been found around Varaždin (N Croatia). Its occurrence in this region can be explained by the expansion of its area of distribution from the central Europe towards the south. Superficially it is quite similar to R. acetosa from which it can be easily distinguished by its longer tap-root, narrower and longer leaf blades and denser inflorescence