A classification of concurrency failures in java components

The Java programming language supports concurrency. Concurrent programs are hard to test due to their inherent non-determinism. This paper presents a classification of concurrency failures that is based on a model of Java concurrency. The model and failure classification is used to justify coverage of synchronization primitives of concurrent components. This is achieved by constructing concurrency flow graphs for each method call. A producer-consumer monitor is used to demonstrate how the approach can be used to measure coverage of concurrency primitives and thereby assist in determining test sequences for deterministic execution.

Ultrasonic measurement technique of burning metals in normal and reduced gravity

The in situ real time measurement of the regression rate of a melting interface (RRMI) is performed by the ultrasonic measurement system reported here. The RRMI is the rate at which a solid/liquid interface (SLI) moves along a metallic rod while burning in an oxygen-enriched atmosphere and is an important flatnmability indicator. The ultrasonic transducer and associated equipment used to drive the transducer and record the echo signal is described, along with the process that transforms the acquired signals into a RRMI value. Test rods of various metals and geometric shapes were burned at several test conditions in different test facilities. The RRMI results with quantified errors are presented and reviewed. The effect of reduced gravity on burning metals is important to space-applications and RRMI results obtained in a reduced gravity environment are also presented.

EFEITOS ESQUELÉTICOS DA TRAÇÃO REVERSA DA MAXILA UTILIZANDO TOMOGRAFIA COMPUTADORIZADA

Este estudo avaliou os efeitos esqueléticos da tração reversa da maxila utilizando imagens 2D (telerradiografia lateral) geradas a partir da tomografia de feixe cônico (imagens 3D). A amostra foi composta por 20 crianças (15 do gênero feminino, e 5 do masculino), com idade variando de 5,6 a 10,7 anos que apresentavam má-oclusão de Classe III de Angle. A tomografia foi realizada antes do tratamento (T1) e logo após o tratamento (T2). O tratamento foi realizado por meio da tração reversa da maxila utilizando-se o aparelho expansor Hyrax associado à máscara facial individualizada, com força de 600 a 800g de cada lado, durante 14 horas por dia. A correção da relação de caninos em Classe I ou com sua sobrecorreção em Classe II foi obtida após 4 a 8 meses de tratamento. Para verificar o erro sistemático e casual foi utilizado o teste t pareado e a fórmula de Dahlberg, respectivamente. O teste t pareado (p<0,05) mostrou diferença significante entre as medidas cefalométricas obtidas em T1 e T2. Na maxila houve aumento do SNA 2,2°, A-Nperp 1,47mm e em Co-A 2,58mm. Na mandíbula, SNB diminuiu -0,54° e P-Nperp, -1,45mm, enquanto Co-Gn aumentou 1,04mm. Houve melhora na relação maxilo-mandibular ANB 2,74° e Wits 4,23mm. As variáveis GoGn.SN, Gn.SN, FH.Md, Mx.Md, e AFAI aumentaram demonstrando que houve uma rotação da mandíbula no sentido horário. O plano palatino rotacionou no sentido anti-horário. Pode se concluir que o tratamento de tração reversa da maxila na idade precoce promoveu uma melhora na relação maxilo-mandibular devido a um avanço da maxila e um deslocamento da mandíbula para baixo e para trás.

AVALIAÇÃO DO PADRÃO ESQUELÉTICO VERTICAL DA FACE NA OCLUSÃO NORMAL NATURAL E NAS MALOCLUSÕES DE ANGLE, E SUA CORRELAÇÃO COM A SÍNFISE MANDIBULAR

O propósito deste estudo foi avaliar cefalometricamente, o padrão esquelético vertical da face em indivíduos com oclusão normal natural e nas diferentes maloclusões e sua correlação com a sínfise mandibular, além de avaliar a presença de dimorfismo sexual. A amostra foi composta de 200 telerradiografias cefalométricas, divididas quanto ao tipo de oclusão, em cinco grupos: grupo A, com pacientes portadores de oclusão normal natural e grupos B, C, D e E, com pacientes portadores de maloclusões, sendo cada grupo, dividido igualmente quanto ao sexo e apresentando idade média entre 13 e 16 anos. A amostra foi classificada em 3 padrões morfológicos verticais da face, de acordo com o índice da altura facial (FHR), proposto por SIRIWAT & JARABAK ou Quociente de Jarabak, em: Hiperdivergente, Neutro e Hipodivergente. Foi utilizada a variável GoMe.VT, da análise de VIGORITO, para avaliar a inclinação da sínfise e sua correlação com os padrões verticais faciais. Após a coleta de dados e da avaliação dos testes estatísticos; qui-quadrado, teste t de Student e da correlação de Pearson, concluiu-se que, o padrão Hipodivergente em todos os pacientes estudados foi o mais frequente, com 70%, sendo que a maior frequência deste padrão foi encontrado na maloclusão Classe II, divisão 2, com 87.5%, existindo outras prevalências de alguns padrões em diferentes classes de oclusões. Foi encontrada uma correlação positiva entre a inclinação da sínfise mandibular e o quociente de Jarabak apenas para a maloclusão Classe I e maloclusão Classe III. Não houve diferença estatisticamente significante entre os sexos e a classificação da morfologia quando comparados os cinco grupos, porém, quando os grupos foram analisados separadamente, foram encontradas diferenças significantes entre os sexos.

AVALIAÇÃO DAS ALTERAÇÕES DENTOESQUELÉTICAS DECORRENTES DO TRATAMENTO DA MALOCLUSÃO DE CLASSE II COM O APARELHO FORSUS POR MEIO DE TOMOGRAFIA COMPUTADORIZADA

Este estudo teve como objetivo avaliar cefalometricamente as alterações dentoesqueléticas decorrentes do tratamento da maloclusão de Classe II, divisão 1, com o aparelho Forsus®, por meio de Tomografia Computadorizada de Feixe Cônico (TCFC). O grupo avaliado foi composto por 10 pacientes, sendo 7 do sexo masculino e 3 do sexo feminino, com idade média de 16,1 anos, maloclusão com severidade mínima de 1/2 Classe II, trespasse horizontal mínimo de 5 mm, padrão facial meso ou braquifacial. Estes jovens se encontravam no estágio IV ou V de maturação óssea, verificada pelas vértebras cervicais. O tempo de uso do aparelho Forsus foi de 7,16 meses (média), período de avaliação compreendido entre a aquisição da primeira teleradiografia gerada através da TCFC (T1 - pré-Forsus) e da segunda teleradiografia (T2 - pós-Forsus). Para análise estatística foi utilizado o teste-t pareado. Os resultados mostraram um pequeno crescimento mandibular que, juntamente com uma diminuição do SNA levaram a uma melhora da relação maxilomandibular. Houve uma rotação no sentido anti-horário da mandíbula e do plano oclusal no sentido horário. Os incisivos superiores foram retruídos, verticalizados e extruídos e os molares superiores distalizaram por inclinação. Houve vestibularização, protrusão e intrusão dos incisivos inferiores, além de mesialização e extrusão dos molares inferiores. Desta maneira, conclui-se que o aparelho Forsus foi efetivo na correção da maloclusão de Classe II, propiciando maiores alterações dentoalveolares do que esqueléticas.(AU)

Structure and activity in assessing antioxidant activity in vitro and in vivo:a critical appraisal illustrated with the flavonoids

Structure–activity relationships are indispensable to identify the most optimal antioxidants. The advantages of in vitro over in vivo experiments for obtaining these relationships are, that the structure is better defined in vitro, since less metabolism takes place. It is also the case that the concentration, a parameter that is directly linked to activity, is more accurately controlled. Moreover, the reactions that occur in vivo, including feed-back mechanisms, are often too multi-faceted and diverse to be compensated for during the assessment of a single structure–activity relationship. Pitfalls of in vitro antioxidant research include: (i) by definition, antioxidants are not stable and substantial amounts of oxidation products are formed and (ii) during the scavenging of reactive species, reaction products of the antioxidants accumulate. Another problem is that the maintenance of a defined concentration of antioxidants is subject to processes such as oxidation and the formation of reaction products during the actual antioxidant reaction, as well as the compartmentalization of the antioxidant and the reactive species in the in vitro test system. So determinations of in vitro structure-activity relationships are subject to many competing variables and they should always be evaluated critically. (c) 2005 Published by Elsevier B.V.

Using DEA and simulation in guiding operating units to improved performance

The potential for the use of DEA and simulation in a mutually supporting role in guiding operating units to improved performance is presented. An analysis following a three-stage process is suggested. Stage one involves obtaining the data for the DEA analysis. This can be sourced from historical data, simulated data or a combination of the two. Stage two involves the DEA analysis that identifies benchmark operating units. In the third stage simulation can now be used in order to offer practical guidance to operating units towards improved performance. This can be achieved by the use of sensitivity analysis of the benchmark unit using a simulation model to offer direct support as to the feasibility and efficiency of any variations in operating practices to be tested. Alternatively, the simulation can be used as a mechanism to transmit the practices of the benchmark unit to weaker performing units by building a simulation model of the weaker unit to the process design of the benchmark unit. The model can then compare performance of the current and benchmark process designs. Quantifying improvement in this way provides a useful driver to any process change initiative that is required to bring the performance of weaker units up to the best in class. © 2005 Operational Research Society Ltd. All rights reserved.

Sympathetic inhibition of accommodation after sustained nearwork in subjects with myopia and emmetropia

PURPOSE. The purposes of the present study were to assess the effect of a sympathetic inhibitory pharmacologic agent, timolol maleate, on the magnitude of nearwork-induced transient myopia (NITM) and its decay in different refractive groups for an extended near task duration and to determine the proportion of the young adult population manifesting effective sympathetic access under naturalistic closed-loop viewing conditions. METHODS. Ten subjects with emmetropia and 10 with myopia were tested. They read binocularly for 1 hour at a distance of 35 to 40 cm. NITM was calculated as the difference in distance refractive state after task as compared with before task immediately after reading. All subjects received timolol maleate to block the sympathetic nervous system and betaxolol as a control agent in independent test sessions separated by at least 3 days. Forty minutes after drug instillation, the NITM measurement procedure was repeated. RESULTS. Initial NITM magnitude was larger in subjects with myopia than in subjects with emmetropia before and after timolol instillation. Furthermore, NITM magnitude in subjects with sympathetic access was increased after timolol instillation. In contrast, with the control agent betaxolol, there was no increase. NITM decay duration to baseline was increased after timolol instillation in the subjects with myopia only. Only 15% of the subjects (n = 3 subjects with myopia) demonstrated effective and significant access to sympathetic facility. CONCLUSIONS. Subjects with myopia demonstrated an increase in decay duration with timolol, thus suggesting impaired sympathetic inhibition of accommodation. This may be a precursor for myopia progression in some persons.

Positioning gender in discourse:a feminist methodology

This book introduces a newly emerging approach to the analysis of talk. FPDA offers a means of analysing the ways in which speakers construct their gender identities within a complex web of power relations. The FPDA approach challenges the traditional feminist view that females are often disempowered within mixed sex settings. This approach shows that both male and female speakers constantly shift between positions of powerfulness and powerlessness - even within the same conversation. The methodology is demonstrated through a study of teenagers' conversations in class and a study of senior managers' discussions in business meetings, concluding with suggestions that while female speakers are often 'silenced' by dominant social discourses, they are far from uniformly powerless.

The development and evaluation of distance learning materials for administrative personnel in a multi-national company

There has been substantial research into the role of distance learning in education. Despite the rise in the popularity and practice of this form of learning in business, there has not been a parallel increase in the amount of research carried out in this field. An extensive investigation was conducted into the entire distance learning system of a multi-national company with particular emphasis on the design, implementation and evaluation of the materials. In addition, the performance and attitudes of trainees were examined. The results of a comparative study indicated that trainees using distance learning had significantly higher test scores than trainees using conventional face-to-face training. The influence of the previous distance learning experience, educational background and selected study environment of trainees was investigated. Trainees with previous experience of distance learning were more likely to complete the course and with significantly higher test scores than trainees with no previous experience. The more advanced the educational background of trainees, the greater the likelihood of their completing the course, although there was no significant difference in the test scores achieved. Trainees preferred to use the materials at home and those opting to study in this environment scored significantly higher than those studying in the office, the study room at work or in a combination of environments. The influence of learning styles (Kolb, 1976) was tested. The results indicated that the convergers had the greatest completion rates and scored significantly higher than trainees with the assimilator, accommodator and diverger learning styles. The attitudes of the trainees, supervisors and trainers were examined using questionnaire, interview and discussion techniques. The findings highlighted the potential problems of lack of awareness and low motivation which could prove to be major obstacles to the success of distance learning in business.

Damage location in structures by monitoring vibration characteristics

The aim of this work was to investigate the feasibility of detecting and locating damage in large frame structures where visual inspection would be difficult or impossible. This method is based on a vibration technique for non-destructively assessing the integrity of structures by using measurements of changes in the natural frequencies. Such measurements can be made at a single point in the structure. The method requires that initially a comprehensive theoretical vibration analysis of the structure is undertaken and from it predictions are made of changes in dynamic characteristics that will occur if each member of the structure is damaged in turn. The natural frequencies of the undamaged structure are measured, and then routinely remeasured at intervals . If a change in the natural frequencies is detected a statistical method. is used to make the best match between the measured changes in frequency and the family of theoretical predictions. This predicts the most likely damage site. The theoretical analysis was based on the finite element method. Many structures were extensively studied and a computer model was used to simulate the effect of the extent and location of the damage on natural frequencies. Only one such analysis is required for each structure to be investigated. The experimental study was conducted on small structures In the laboratory. Frequency changes were found from inertance measurements on various plane and space frames. The computational requirements of the location analysis are small and a desk-top micro computer was used. Results of this work showed that the method was successful in detecting and locating damage in the test structures.

Effects of some 5-hydroxytryptamine and related ligands in anxiety models

Drugs acting at 5-HT receptors were evaluated on three animal models of anxiety. On the elevated X-maze test the majority of 5-HT1 agonists were found to be anxiogenic. However, ipsapirone was anxiolytic and buspirone and gepirone were inactive. The 5-HT2 agonist DOI and the 5-HT2 antagonist ritanserin were anxiolytic while ICI 169,369, a 5-HT2 antagonist was inactive. All 5-HT3 antagonists tested were inactive in this test, while the indirect serotomimetics zimeldine and fenfluramine were anxiogenic. Neither beta-adrenoceptor agonists nor antagonists had reproducible effects on anxiety in this model. Combined beta-1/beta-2 adrenoceptor antagonists reversed the anxiogenic effects of 8-OH-DPAT while selective beta-1 or beta-2 antagonists did not. On the social interaction model the 5-HT1 agonists 8-OH-DPAT, RU 24969 and 5-MeODMT were anxiogenic and ipsapirone was anxiolytic. The 5-HT2 agonist DOI and the beta-adrenoceptor- and 5-HT- antagonist pindolol were anxiolytic, while the 5-HT2 and 5-HT3 antagonists were inactive. In the marble burying test, the 5-HT upake inhibitors zimeldine, fluvoxamine, indalpine and citalopram, the 5-HT1B/5-HT1C agonists mCPP and TFMPP and the 5-HT2/5-HT1C agonist DOI reduced marble burying without affecting locomotor activity. 5-HT1A agonists and the 5-HT2 and 5-HT3 antagonists were without effect. Lesions of the dorsal raphe nucleus reversed the anxiogenic effects of 8-OH-DPAT in the X-maze model. The implication of these results for the understanding of the pharmacology of 5-HT in anxiety is discussed.

Land use monitoring in the Nigerian savanna using aerial photographs

Aerial photography was used to determine the land use in a test area of the Nigerian savanna in 1950 and 1972. Changes in land use were determined and correlated with accessibility, appropriate low technology methods being used to make it easy to extend the investigation to other areas without incurring great expense. A test area of 750 sq km was chosen located in Kaduna State of Nigeria. The geography of the area is summarised together with the local knowledge which is essential for accurate photo interpretation. A land use classification was devised and tested for use with medium scale aerial photography of the savanna. The two sets of aerial photography at 1:25 000 scale were sampled using systematic dot grids. A dot density of 8 1/2 dots per sq km was calculated to give an acceptable estimate of land use. Problems of interpretation included gradation between categories, sample position uncertainty and personal bias. The results showed that in 22 years the amount of cultivated land in the test area had doubled while there had been a corresponding decrease in the amount of uncultivated land particularly woodland. The intensity of land use had generally increased. The distribution of land use changes was analysed and correlated with accessibility. Highly significant correlations were found for 1972 which had not existed in 1950. Changes in land use could also be correlated with accessibility. It was concluded that in the 22 year test period there had been intensification of land use, movement of human activity towards the main road, and a decrease in natural vegetation particularly close to the road. The classification of land use and the dot grid method of survey were shown to be applicable to a savanna test area.

The mosaic test:benchmarking colour-based image retrieval systems using image mosaics

Evaluation and benchmarking in content-based image retrieval has always been a somewhat neglected research area, making it difficult to judge the efficacy of many presented approaches. In this paper we investigate the issue of benchmarking for colour-based image retrieval systems, which enable users to retrieve images from a database based on lowlevel colour content alone. We argue that current image retrieval evaluation methods are not suited to benchmarking colour-based image retrieval systems, due in main to not allowing users to reflect upon the suitability of retrieved images within the context of a creative project and their reliance on highly subjective ground-truths. As a solution to these issues, the research presented here introduces the Mosaic Test for evaluating colour-based image retrieval systems, in which test-users are asked to create an image mosaic of a predetermined target image, using the colour-based image retrieval system that is being evaluated. We report on our findings from a user study which suggests that the Mosaic Test overcomes the major drawbacks associated with existing image retrieval evaluation methods, by enabling users to reflect upon image selections and automatically measuring image relevance in a way that correlates with the perception of many human assessors. We therefore propose that the Mosaic Test be adopted as a standardised benchmark for evaluating and comparing colour-based image retrieval systems.

Modelling and experimental verification of a solar-powered liquid desiccant cooling system for greenhouse food production in hot climates

Experiments and theoretical modelling have been carried out to predict the performance of a solar-powered liquid desiccant cooling system for greenhouses. We have tested two components of the system in the laboratory using MgCl2 desiccant: (i) a regenerator which was tested under a solar simulator and (ii) a desiccator which was installed in a test duct. Theoretical models have been developed for both regenerator and desiccator and gave good agreement with the experiments. The verified computer model is used to predict the performance of the whole system during the hot summer months in Mumbai, Chittagong, Muscat, Messina and Havana. Taking examples of temperate, sub-tropical, tropical and heat-tolerant tropical crops (lettuce, soya bean, tomato and cucumber respectively) we estimate the extensions in growing seasons enabled by the system. Compared to conventional evaporative cooling, the desiccant system lowers average daily maximum temperatures in the hot season by 5.5-7.5 °C, sufficient to maintain viable growing conditions for lettuce throughout the year. In the case of tomato, cucumber and soya bean the system enables optimal cultivation through most summer months. It is concluded that the concept is technically viable and deserves testing by means of a pilot installation at an appropriate location.