Measuring higher order optical aberrations of the human eye: techniques and applications

In the present paper we discuss the development of "wave-front", an instrument for determining the lower and higher optical aberrations of the human eye. We also discuss the advantages that such instrumentation and techniques might bring to the ophthalmology professional of the 21st century. By shining a small light spot on the retina of subjects and observing the light that is reflected back from within the eye, we are able to quantitatively determine the amount of lower order aberrations (astigmatism, myopia, hyperopia) and higher order aberrations (coma, spherical aberration, etc.). We have measured artificial eyes with calibrated ametropia ranging from +5 to -5 D, with and without 2 D astigmatism with axis at 45º and 90º. We used a device known as the Hartmann-Shack (HS) sensor, originally developed for measuring the optical aberrations of optical instruments and general refracting surfaces in astronomical telescopes. The HS sensor sends information to a computer software for decomposition of wave-front aberrations into a set of Zernike polynomials. These polynomials have special mathematical properties and are more suitable in this case than the traditional Seidel polynomials. We have demonstrated that this technique is more precise than conventional autorefraction, with a root mean square error (RMSE) of less than 0.1 µm for a 4-mm diameter pupil. In terms of dioptric power this represents an RMSE error of less than 0.04 D and 5º for the axis. This precision is sufficient for customized corneal ablations, among other applications.

Pulssimuodon vaikutus valokaaren käytettävyyteen pulssi-MIG/MAG-hitsauksessa

Käytettävyydeltään huippuluokkaa olevan pulssi-MIG/MAG-hitsausvalokaaren toteuttaminen vaatii runsaasti tietoa eri pulssiparametreista ja niiden vaikutuksista hitsaukseen. Näihin vaikutuksiin liittyvä tieteellinen tutkimus on ollut melko vähäistä. Erityisesti tieto pulssimuodon vaikutuksista hitsausääneen on perustunut lähinnä kokemuksen tuomaan tuntumaan. Tässä diplomityössä tutkittiin pulssimuodon vaikutusta valokaaren käytettävyyteen pulssi-MIG/MAG-hitsauksessa. Käytettävyys käsittää tässä tapauksessa hitsausäänen, hitsin geometrian ja hitsausominaisuudet. Tutkimuksen alussa perehdyttiin kirjallisuuteen ja tuoreimpiin tutkimuksiin, jonka jälkeen vertailtiin erilaisia pulssimuotoja keskenään hitsauskokeiden avulla. Hitsausääneen ja hitsin geometriaan liittyvät kokeet suoritettiin mekanisoidusti. Hitsausääneen liittyvät mittaukset suoritettiin luokan 1 äänitasomittarilla ja tuloksia analysoitiin tietokoneohjelmistolla. Hitsien geometrioiden vertailu suoritettiin makrohietutkimuksena. Hitsausominaisuuksia tutkittiin suurnopeuskameran ja oskilloskoopin, sekä lopulta käsinhitsauskokeiden avulla. Kaikissa koevaiheissa pulssimuodon tarkasteluun käytettiin oskilloskooppia. Lisäksi käytössä oli toinen oskilloskooppi, jolla tarkasteltiin hitsausvirran spektriä. Pulssimuodon muokkaamiseen käytettiin erillistä tietokoneohjelmaa. Työn kokeellinen osuus keskittyi pulssi-MAG-hitsaukseen. Pulssimuotoa muokkaamalla saatiin aikaan miellyttävämpi hitsausääni. Lisäksi havaittiin, että pulssimuotoa muokkaamalla hitsistä saadaan kapeampi, jolloin juuritunkeumaa saavutetaan enemmän. Käsinhitsauskokeet osoittivat muokatun pulssimuodon olevan myös hitsaajan näkökulmasta käytettävyydeltään paras pulssimuoto. Erityisesti valokaaren vakaus ja kohdistuvuus sekä suurien hitsausnopeuksien sietokyky olivat muokatun pulssimuodon etuja. Selviä haittavaikutuksia pulssimuodon muokkaamiselle ei löydetty.

Attention in schizophrenia and in epileptic psychosis

The adaptive behavior of human beings is usually supported by rapid monitoring of outstanding events in the environment. Some investigators have suggested that a primary attention deficit might trigger symptoms of schizophrenia. In addition, researchers have long discussed the relationship between schizophrenia and the schizophrenia-like psychosis of epilepsy (SLPE). On the basis of these considerations, the objective of the present study was to investigate attention performance of patients with both disorders. Patient age was 18 to 60 years, and all patients had received formal schooling for at least four years. Patients were excluded if they had any systemic disease with neurologic or psychiatric comorbidity, or a history of brain surgery. The computer-assisted TAVIS-2R test was applied to all patients and to a control group to evaluate and discriminate between selective, alternating and sustained attention. The TAVIS-2R test is divided into three parts: one for selective attention (5 min), the second for alternating attention (5 min), and the third for the evaluation of vigilance or sustained attention (10 min). The same computer software was used for statistical analysis of reaction time, omission errors, and commission errors. The sample consisted of 36 patients with schizophrenia, 28 with interictal SLPE, and 47 healthy controls. The results of the selective attention tests for both patient groups were significantly lower than that for controls. The patients with schizophrenia and SLPE performed differently in the alternating and sustained attention tests: patients with SLPE had alternating attention deficits, whereas patients with schizophrenia showed deficits in sustained attention. These quantitative results confirmed the qualitative clinical observations for both patient groups, that is, that patients with schizophrenia had difficulties in focusing attention, whereas those with epilepsy showed perseveration in attention focus.

Morphometric analysis of the phrenic nerve in male and female Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR)

Ventilatory differences between rat strains and genders have been described but the morphology of the phrenic nerve has not been investigated in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. A descriptive and morphometric study of the phrenic nerves of male (N = 8) and female (N = 9) SHR, and male (N = 5) and female (N = 6) WKY is presented. After arterial pressure and heart rate recordings, the phrenic nerves of 20-week-old animals were prepared for epoxy resin embedding and light microscopy. Morphometric analysis performed with the aid of computer software that took into consideration the fascicle area and diameter, as well as myelinated fiber profile and Schwann cell nucleus number per area. Phrenic nerves were generally larger in males than in females on both strains but larger in WKY compared to SHR for both genders. Myelinated fiber numbers (male SHR = 228 ± 13; female SHR = 258 ± 4; male WKY = 382 ± 23; female WKY = 442 ± 11 for proximal right segments) and density (N/mm²; male SHR = 7048 ± 537; female SHR = 10355 ± 359; male WKY = 9457 ± 1437; female WKY = 14351 ± 1448) for proximal right segments) were significantly larger in females of both groups and remarkably larger in WKY than SHR for both genders. Strain and gender differences in phrenic nerve myelinated fiber number are described for the first time in this experimental model of hypertension, indicating the need for thorough functional studies of this nerve in male and female SHR.

Measurement of growth in the lichen Rhizocarpon geographicum using a new photographic technique

Lichenologists and users of lichenometry have long used calipers or photogrammetry to measure the growth of crustose lichens. Now, digital photography and popular computer software provide methodological alternatives. This thesis developed and tested a new methodology for tracking change and growth of the lichen, Rhizocarpon geographicum. Adobe Photoshop CS3 Extended software and a photographic time series (1996,2003,2006 and 2007) were used to measure thallus diameter, area, prothallus width and areolae area in 115 small R. geographicum thalli (0.53-1049.88 mm2 ). Measures of 8 diameters per thallus showed that change in diameter was highly variable and is a weak index of growth. Thallus area was a reliable measure of growth (power correlation, R2 = 0.89). Rapid, highly irregular growth occurred in small thalli «30 mm2 ), and steady, uniform growth occurred in larger thalli (>30 mm2 ). This new methodology is tedious but can potentially generate accurate and precise measures for even the tiniest of lichens.

Imagery, Technology, and Remote Adult Aboriginal Teacher Candidates: A Brock University Pilot Project

The aim of this thesis is to explore the relationship between imagery, technology, and remote adult Aboriginal teacher candidates through the computer software Elluminate Live. It focuses on the implications that the role imagery plays in third generation distance education with these learners and the new media associated therein. The thesis honours the Medicine Wheel teachings and is presented within this cyclical framework that reflects Indigenous philosophies and belief systems. In accordance, Sharing Circle as methodology is used to keep the research culturally grounded, and tenets of narrative inquiry further support the study. Results indicate there are strong connections to curricula enhanced with imagery—most notably a spiritual connection. Findings also reveal that identity associated to geographical location is significant, as are supportive networks. Third generation distance education, such as Elluminate Live, needs to be addressed before Aboriginal communities open the doors to all it encompasses, and although previous literature peers into various elements, this study delves into why the graphical interface resonates with members of these communities. Of utmost importance is the insight this thesis lends to the pedagogy that may possibly evoke a transformative learning process contributing to the success rate of Aboriginal learners and benefit Aboriginal communities as a whole.

Aircraft down-range profiles formed from simulated and compact-range radar backscatter

Compact-range radar backscatter measurements are taken of aircraft scale models. In addition, computer software is used to predict the RCS of the aircraft. Synthetic down-range profiles formed from the two sources of backscatter data are compared and visualized in an innovative manner. Similar discrimination rates between the two aircraft are obtained on data from both source

Infohabitants: laboratori per la simulació d’ infohabitants com agents recomanadors (SIRA)

L’ objectiu del projecte és la implementació d’un simulador de sistema de recomanació que permeti estudiar algoritmes de dissociació entre agent-recomanador i usuari, combinant-los amb diverses tècniques de recomanació i fent servir infohabitants com Agents Recomanadors i veure com treballen en un sistema recomanador

La Nova versió ACME

Amb la perspectiva d’implantació de l’Espai Europeu d’Educació Superior (EEES) s’ha produït la proliferació de noves metodologies i eines docents, canvis de plans docents,etc. Tots aquests canvis i millores tenen com a eix central l’aprenentatge dels estudiants en contraposició del concepte més tradicional d’ensenyament centrat en el que explica el professor. És per això que s’han iniciat tota una sèrie d’iniciatives, entre les quals es troba diferents plataformes webs, per tal de realitzar canvis i millores en les metodologies. Una d’aquestes plataformes que s’estan utilitzant en la implantació de l’EEES és l’ACME. La plataforma ACME va sorgir de la iniciativa d’uns quants professors del Departament de Informàtica i Matemàtica Aplicada de la UdG amb l’esperit de poder oferir quaderns d’exercicis personalitzats als alumnes. Ja fa 10 anys de la creació de la plataforma ACME. En aquests deu anys s’han afegit moltes eines i molta tipologia d’exercicis nous, però no s’ha tocat l’entorn visual, tot i l’evident evolució tant en matèria de disseny com en tecnologia web que hi ha hagut en la darrera dècada. És per això que ha esdevingut necessari introduir tot un seguit de millores tant a l’aspecte com al sistema de navegació de l’ACME per tal de facilitar les tasques al gran nombre d’usuaris de l’eina. El que es pretén en aquest Projecte Final de Carrera és millorar l’aspecte de l’ACME i adaptar-lo a les noves necessitats que es plantegen amb la implantació de l’Espai Europeu d’Educació Superior (EEES), així com afegir noves funcionalitats per crear una eina adequada pels estudis que l’utilitzen. Per tant podem resumir que els objectius d’aquest Projecte Final de Carrera són: actualitzar la imatge de l’ACME i millorar la seva navegació; incorporar elements que ens permetin utilitzar eines de la web 2.0; facilitar l’ús de les diferents eines que incorpora l’ACME homogeneïtzant criteris i crear un espai personal per l’usuari on emmagatzemar fitxers

Multidimensional Adaptations for Open Learning Management Systems

Our work is focused on alleviating the workload for designers of adaptive courses on the complexity task of authoring adaptive learning designs adjusted to specific user characteristics and the user context. We propose an adaptation platform that consists in a set of intelligent agents where each agent carries out an independent adaptation task. The agents apply machine learning techniques to support the user modelling for the adaptation process

Adaptive intelligent agent approach to guide the web navigation on the PLAN-G distance learning platform

Hypermedia systems based on the Web for open distance education are becoming increasingly popular as tools for user-driven access learning information. Adaptive hypermedia is a new direction in research within the area of user-adaptive systems, to increase its functionality by making it personalized [Eklu 961. This paper sketches a general agents architecture to include navigational adaptability and user-friendly processes which would guide and accompany the student during hislher learning on the PLAN-G hypermedia system (New Generation Telematics Platform to Support Open and Distance Learning), with the aid of computer networks and specifically WWW technology [Marz 98-1] [Marz 98-2]. The PLAN-G actual prototype is successfully used with some informatics courses (the current version has no agents yet). The propased multi-agent system, contains two different types of adaptive autonomous software agents: Personal Digital Agents {Interface), to interacl directly with the student when necessary; and Information Agents (Intermediaries), to filtrate and discover information to learn and to adapt navigation space to a specific student

Dynamic bandwidth management as part of an integrated network management system based on distributed agents

We present a system for dynamic network resource configuration in environments with bandwidth reservation and path restoration mechanisms. Our focus is on the dynamic bandwidth management results, although the main goal of the system is the integration of the different mechanisms that manage the reserved paths (bandwidth, restoration, and spare capacity planning). The objective is to avoid conflicts between these mechanisms. The system is able to dynamically manage a logical network such as a virtual path network in ATM or a label switch path network in MPLS. This system has been designed to be modular in the sense that in can be activated or deactivated, and it can be applied only in a sub-network. The system design and implementation is based on a multi-agent system (MAS). We also included details of its architecture and implementation

Desenvolupament d'un agent intel·ligent dins el marc de la competició TAC SCM

Aquest projecte està emmarcat dins el grup eXiT d’Intel•lig`encia Artificial del Departament d’Electrònica i Automàtica (EIA) de la Universitat de Girona. Pertany a l’àmbit de la Intel•ligència Artificial i, concretament, en l’apartat d’agents intel•ligents. En el nostre cas, tractarem el desenvolupament d’un agent intel•ligent en un entorn determinat, el de la gestió d’una cadena de producció. Amb l’objectiu de proporcionar un marc experimental on provar diferents tecnologies de suport a la gestió de la cadena de producció, la comunitat d’investigadors va proposar una competició internacional: la Trading Agent Competiton (TAC). En aquesta competició existeixen diferents modalitats. En particular, la Swedish Institution of Computer Science (SICS), juntament amb la Carnegie Mellon University de Pittsburg, Minnesotta, van proposar al 2003 un escenari de muntatge de PC’s basat en el proveïment de recursos, l’embalatge de PC’s i les ventes a clients. Aquesta modalitat és coneguda com a TAC-SCM (Supply Chain Management)

I-SS: integrated supervision systems approach based on interactive components

Process supervision is the activity focused on monitoring the process operation in order to deduce conditions to maintain the normality including when faults are present Depending on the number/distribution/heterogeneity of variables, behaviour situations, sub-processes, etc. from processes, human operators and engineers do not easily manipulate the information. This leads to the necessity of automation of supervision activities. Nevertheless, the difficulty to deal with the information complicates the design and development of software applications. We present an approach called "integrated supervision systems". It proposes multiple supervisors coordination to supervise multiple sub-processes whose interactions permit one to supervise the global process

A Negotiation Style Recommender Based on Computational Ecology in Open Negotiation Environments

The system described herein represents the first example of a recommender system in digital ecosystems where agents negotiate services on behalf of small companies. The small companies compete not only with price or quality, but with a wider service-by-service composition by subcontracting with other companies. The final result of these offerings depends on negotiations at the scale of millions of small companies. This scale requires new platforms for supporting digital business ecosystems, as well as related services like open-id, trust management, monitors and recommenders. This is done in the Open Negotiation Environment (ONE), which is an open-source platform that allows agents, on behalf of small companies, to negotiate and use the ecosystem services, and enables the development of new agent technologies. The methods and tools of cyber engineering are necessary to build up Open Negotiation Environments that are stable, a basic condition for predictable business and reliable business environments. Aiming to build stable digital business ecosystems by means of improved collective intelligence, we introduce a model of negotiation style dynamics from the point of view of computational ecology. This model inspires an ecosystem monitor as well as a novel negotiation style recommender. The ecosystem monitor provides hints to the negotiation style recommender to achieve greater stability of an open negotiation environment in a digital business ecosystem. The greater stability provides the small companies with higher predictability, and therefore better business results. The negotiation style recommender is implemented with a simulated annealing algorithm at a constant temperature, and its impact is shown by applying it to a real case of an open negotiation environment populated by Italian companies