7,650 research outputs found
Methods and metrics for selective regression testing
In corrective software maintenance, selective regression testing includes test selection from previously-run test suites and test coverage identification. We propose three reduction-based regression test selection methods and two McCabe-based coverage identification metrics (T. McCabe, 1976). We empirically compare these methods with three other reduction- and precision-oriented methods, using 60 test problems. The comparison shows that our proposed methods yield favourable result
Conflict management approaches in Palestinian Baptist intra-church conflict in Israel between 1990 and 2016, in dialogue with Miroslav Volfâs theology of reconciliation: an analysis and critical evaluation
In the early 1990s, the International Mission Board of the Southern Baptist Convention, changed its global philosophy of ministry and withdrew from direct involvement in the Baptist churches it planted, including in Israel. Around the same time, local churches started to split.
This research project seeks to contribute towards a solution to this problem by asking and answering both a sociological and a theological question: Sociologically, what are the nature and causes of the splits and how do Palestinian Baptist churches manage such intra-church conflict? Theologically, what are the desirable conflict management practices and how should they be adapted to local cultural traditions? The primary purpose of this research is to generate a local theory regarding a Palestinian theology of reconciliation which is both theologically and culturally relevant.
This thesis argues that the primary factor for church splits is the clash between the pastorsâ legacy of a âhierarchical-patriarchalâ approach and the younger generation's âCongregationalist-democraticâ approach, both grounded in, but each offering a different interpretation of Christian theology and Arab culture. It identifies four conflict management practices that are implemented by Palestinian Baptists in Israeli and holds that the main reason that the conflicts have not been resolved effectively is the clash between contenders' interpretations of theology and culture. The pastorsâ cultural-theological approach is a combination of traditional sulha and hierarchical theology that was customary in traditional Palestinian churches. By contrast, the younger generationâs cultural-theological approach is a combination of alternative-legalist and Western-Baptist.
The thesis examines the relevance of Miroslav Volfâs theology of reconciliation for the cases at hand. It argues that the model is indeed pertinent to Palestinian Baptists in Israel, who are in the process of investing new meanings into their theology of reconciliation. Yet, in order to be applicable to this context it requires cultural translation in eight elements: formality, dignity, venting, community, church practices, the not necessarily linear nature of the reconciliation process, to view divine justice as compatible with divine love and thus not separate them during conflict, and since conditional and unconditional forgiveness have much in common and differ in the way reconciliation is realized the focus should be on achieving reconciliation
A notion of graph likelihood and an infinite monkey theorem
We play with a graph-theoretic analogue of the folklore infinite monkey
theorem. We define a notion of graph likelihood as the probability that a given
graph is constructed by a monkey in a number of time steps equal to the number
of vertices. We present an algorithm to compute this graph invariant and closed
formulas for some infinite classes. We have to leave the computational
complexity of the likelihood as an open problem.Comment: 6 pages, 1 EPS figur
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Simulation discounted cash flow valuation for internet companies
Discounted cash flow (DCF) is the most accepted approach for company valuation. It is well grounded in theory and practice. However, the DCF approach, which is commonly used for traditional companies valuation, presents a number of serious weaknesses within the Internet companiesâ context. One of these weaknesses is tackling the uncertainty that characterize future cash flows of these companies. Specifically DCF assumes that future cash flow streams are highly predictable. The effects of uncertainty are therefore tackled implicitly by discounting the expected value of the cash flows at a risk-adjusted interest rate. However, under uncertainty, future cash flows of these companies can no longer be characterized by a single value but rather by a range of values of its possible consequences. This paper looks at the way in which uncertainty can be incorporated into the traditional DCF approach so that the latter, which is otherwise conceptually sound, becomes relevant. This is done by recognizing that the DCF input variables are uncertain and will have a probability distribution pertaining to each of them. Thus by utilizing a probability-based valuation model (using Monte Carlo Simulation) it is possible to incorporate uncertainty into the analysis and address the shortcomings of the current model. The MC simulation assigns a range of values in order to cope with uncertainty underlies each key cash flow variable. The process leads to a probability distribution of the valuation criterion used, giving investors a quantitative measure of risk involved
Developing a preliminary recharge model of the Nile Basin to help interpret GRACE data
GRACE data provides a new and exciting opportunity to gain a direct and independent measure of water mass variation on a regional scale, but the data must be combined with hydrological modelling to indicate in which part of the water cycle the mass change has occurred. Processing GRACE data through a series of spectral filters indicates a seasonal variation to gravity mass (±0.005 mGal) thought to relate to the downstream movement of water in the catchment, and delayed storage from groundwater, following the wet season in the upper catchment.
To help interpret these data a groundwater recharge model was developed for the Nile Catchment using the model ZOODRM (a distributed modelling code for calculating spatial and temporal variations in groundwater recharge). ZOODRM was an appropriate model to use for this work, due to the lower data demands of the model, relative to other groundwater models, the ability of the model to use entirely remotely-sensed input data, and the added functionality of runoff routing. Rainfall (NOAA data) and ET data were sourced from the FEWS NET African Data Dissemination Service. Geological data was sourced from the digital geology map of the world, landuse data from the USGS and the DEM data from ESRI.
Initial model results indicate groundwater recharge across the basin of 0-4mma-1, with obvious considerable spatial variability. The results indicate the importance of groundwater in storing rainfall, and releasing it slowly throughout the year in different parts of the catchment. Only by modelling this process can GRACE data be reliably interpreted hydrologically. Despite only a qualitative interpretation of the GRACE data having been achieved within this preliminary study, the work has indicated that the ZOODRM model can be used with entirely remotely-sensed data, and that sufficient data exists for the Nile Basin to construct a plausible recharge model. Future work is now required to properly calibrate the model to enable closer comparison of the Nile GRACE data
Multilevel Double Loop Monte Carlo and Stochastic Collocation Methods with Importance Sampling for Bayesian Optimal Experimental Design
An optimal experimental set-up maximizes the value of data for statistical
inferences and predictions. The efficiency of strategies for finding optimal
experimental set-ups is particularly important for experiments that are
time-consuming or expensive to perform. For instance, in the situation when the
experiments are modeled by Partial Differential Equations (PDEs), multilevel
methods have been proven to dramatically reduce the computational complexity of
their single-level counterparts when estimating expected values. For a setting
where PDEs can model experiments, we propose two multilevel methods for
estimating a popular design criterion known as the expected information gain in
simulation-based Bayesian optimal experimental design. The expected information
gain criterion is of a nested expectation form, and only a handful of
multilevel methods have been proposed for problems of such form. We propose a
Multilevel Double Loop Monte Carlo (MLDLMC), which is a multilevel strategy
with Double Loop Monte Carlo (DLMC), and a Multilevel Double Loop Stochastic
Collocation (MLDLSC), which performs a high-dimensional integration by
deterministic quadrature on sparse grids. For both methods, the Laplace
approximation is used for importance sampling that significantly reduces the
computational work of estimating inner expectations. The optimal values of the
method parameters are determined by minimizing the average computational work,
subject to satisfying the desired error tolerance. The computational
efficiencies of the methods are demonstrated by estimating the expected
information gain for Bayesian inference of the fiber orientation in composite
laminate materials from an electrical impedance tomography experiment. MLDLSC
performs better than MLDLMC when the regularity of the quantity of interest,
with respect to the additive noise and the unknown parameters, can be
exploited
Comment encourager plus de femmes vers lâInformatique?
Abstract : Only a small minority of women are drawn to the field of Computer Science (CS). For many years, the ratio of female students at all the Cegeps/colleges in the province of Quebec attending and completing Computer Science programs has been much lower than the number of males. Women experience various challenges during the process of becoming computer scientists. Therefore, greater attention needs to be allocated to research that investigates the gender inequality phenomenon in the CS environment. This study looks at both female and male students who are currently attending a Computer Science program at the Cegep level at LaSalle College in Montreal. The purpose was to identify whether similarities or patterns exist at the social and/or affective levels that lead some female students to choose Computer Science as an academic program. The study also aims to identify the possible social and affective factors that are discouraging female students from registering in Computer Science. Such factors may be influencing their levels of confidence and interest, and consequently steering female students away from pursuing CS as an academic and career choice. Finally, we identify learning strategies that help those who pursue it to succeed in the program. A mixed research method was implemented. A quantitative study used the admissions records of all Cegeps in the province of Quebec, both English and French, in order to analyze and compare the number of applicants who have attended and completed a Computer Science specialization between 2005 and 2016. An exploratory qualitative study was carried out in the form of interviews with a participating sample of twenty-four students (F=12, M=12) currently attending LaSalle College in the field of Computer Science.Seule une petite minoritĂ© de femmes est attirĂ©e par le domaine de lâinformatique. Les facteurs Ă©tudiĂ©s pourraient affecter leur niveau de confiance et dâintĂ©rĂȘt et par consĂ©quent les Ă©loigner de choisir cette discipline en tant que cursus acadĂ©mique ou dâentreprendre une carriĂšre professionnelle en informatique. Cette Ă©tude examine les facteurs sociaux et affectifs qui amĂšnent les Ă©tudiantes Ă choisir l'informatique comme option acadĂ©mique au CollĂšge LaSalle au niveau du CĂ©gep. Une mĂ©thode de recherche mixte utilisant des approches quantitatives et qualitatives a Ă©tĂ© mise en oeuvre dans cette Ă©tude. Cinq pistes de rĂ©flexions ou questions ont Ă©tĂ© explorĂ©es pour mesurer si l'un des facteurs sociaux ou affectifs Ă©tudiĂ©s pouvait avoir influencĂ© le choix des Ă©tudiantes Ă choisir lâinformatique en tant qu'option acadĂ©mique ou contribuĂ© Ă augmenter leur confiance en soi pour mieux rĂ©ussir dans le programme. Dans la premiĂšre piste, nous avons analysĂ© lâinfluence de l'exposition prĂ©alable des Ă©tudiantes au cours de leurs vies ou au cours de leurs Ă©tudes actuelles Ă des modĂšles fĂ©minins, de leaders ou de mentors sur le choix de lâinformatique comme option. La seconde piste portait sur l'effet des prĂ©jugĂ©s et les idĂ©es prĂ©conçues sur la place de la femme dans ce secteur dâactivitĂ© qui est lâinformatique. En troisiĂšme lieu, nous avons examinĂ© lâimpact que pouvait avoir l'exposition prĂ©coce aux ordinateurs lors de la croissance alors que la quatriĂšme piste consistait Ă examiner lâeffet des encouragements et du soutien de lâenvironnement immĂ©diat des femmes concernĂ©es. Enfin, une cinquiĂšme question a portĂ© sur le fait de savoir si l'intĂ©rĂȘt et lâattitude positive que portaient les femmes Ă lâĂ©gard de lâinformatique avaient menĂ© au choix de ce domaine et par consĂ©quent, augmentĂ© la confiance en soi pour mener Ă bien leur programme d'Ă©tudes. Une mĂ©thode quantitative a Ă©tĂ© utilisĂ©e pour analyser les dossiers d'admission des programmes de lâinformatique de tous les cĂ©geps de la province de QuĂ©bec, en comparant le nombre de candidats de sexe masculin qui ont suivi et complĂ©tĂ© leurs programmes pour les dix annĂ©es sâĂ©talant de 2005 Ă 2016. Les rĂ©sultats montrent quâune trĂšs petite minoritĂ© d'Ă©tudiantes ont frĂ©quentĂ© les programmes informatiques dans les collĂšges de la province comparativement Ă un milieu fortement dominĂ©s par les hommes. Une approche exploratoire qualitative a Ă©tĂ© mise en oeuvre dans le cadre d'une entrevue individuelle menĂ©e auprĂšs de 24 participants (N = 24, M = 12, F = 12) participant aux programmes informatiques du CollĂšge LaSalle au niveau du DEC quâau niveau de lâAEC. Les rĂ©ponses collectĂ©es et analysĂ©es Ă partir de ces entrevues ont permis de rĂ©pondre Ă toutes les questions de recherche posĂ©es. En ce qui concerne la premiĂšre question, la compilation des rĂ©sultats a montrĂ© que la majoritĂ© des participantes n'ont pas eu dans leur milieu de vie des modĂšles fĂ©minins ayant Ă©tudiĂ© ou oeuvrĂ© dans le domaine de lâinformatique alors que deux participantes ont connu des modĂšles masculins. Cependant, cela ne les a pas empĂȘchĂ©s de choisir lâinformatique comme choix acadĂ©mique ou professionnel. Par ailleurs, lâĂ©tude a montrĂ© quâune fois engagĂ©es dans le programme et lorsquâelles reçoivent du soutien et des conseils de la part dâun mentor ou d'un pair, cela devenait un facteur de motivation trĂšs important qui les poussait Ă poursuivre le cursus dans lequel elles Ă©taient engagĂ©es. Les participants masculins quant Ă eux ont surtout Ă©tĂ© influencĂ© par des modĂšles masculins dans leur entourage immĂ©diat famille et amis ainsi que par des icĂŽnes du monde industriel et mĂ©diatique. Le point commun entre les deux populations est que les participants sont d'accord sur le fait que la prĂ©sence dâun mentor est nĂ©cessaire surtout pendant le premier semestre du parcours scolaire. Ils insistent aussi sur le fait que le soutien par les pairs est trĂšs utile pour bĂątir des connaissances et partager des expĂ©riences. Cependant, les participant masculins diffĂ©raient de leurs homologues fĂ©minins qui ont dit prĂ©fĂ©rer des femmes comme mentors parce qu'elles se sentaient plus soutenues et comprises et donc plus en confiance. Ces mentors Ă©taient nĂ©cessaires pour un soutien technique et Ă©motionnel. Beaucoup d'hommes comptaient encore plus sur leurs collĂšgues masculins que sur leurs collĂšgues fĂ©minins pour le soutien scolaire. En ce qui concerne la seconde question, lâĂ©tude a rĂ©vĂ©lĂ© que plus de la moitiĂ© des participants hommes et femmes, avaient des idĂ©es fausses ou prĂ©conçues sur lâimplication des femmes dans le mode de lâinformatique, idĂ©es qui ont Ă©tĂ© rapidement effacĂ©es une fois qu'ils ont commencĂ© le programme. Par consĂ©quent, il est Ă©vident que ces notions prĂ©conçues n'ont pas affectĂ© la dĂ©cision des participantes de poursuivre dans le domaine de lâinformatique. La troisiĂšme question portait sur leur exposition antĂ©rieure et leur expĂ©rience avec les ordinateurs. Encore une fois, les rĂ©sultats de lâĂ©tude ont montrĂ© que l'exposition des hommes aux ordinateurs et au matĂ©riel informatique Ă©tait plus Ă©levĂ©e que celle des femmes. Cependant, cela nâa pas dissuadĂ©s les femmes de choisir d'Ă©tudier en informatique. L'obstacle principal que les femmes ont soulignĂ© Ă©tait le manque de connaissances techniques et de pratique qui se traduisent par un processus d'apprentissage plus ardu afin de se familiariser avec les nombreuses technologies et dont elles croient que leurs collĂšgues masculins sont dĂ©jĂ Ă l'aise avec. Ce manque d'expĂ©rience a affectĂ© leur confiance en soi et les a souvent dĂ©motivĂ©s, alors que ce n'Ă©tait pas un problĂšme majeur pour la majoritĂ© des hommes qui se rĂ©fĂ©raient trĂšs souvent vers les ressources en ligne et le soutien par les pairs pour progresser dans leur apprentissage. La quatriĂšme question portait sur lâeffet de l'encouragement et le soutien de leur entourage immĂ©diat. Lâanalyse des rĂ©sultats a montrĂ© que tous les Ă©tudiants semblent avoir dĂ©cidĂ© de rejoindre un des programmes informatiques de leur plein grĂ©, avec ou sans le soutien familial. Pourtant, une fois inscrits dans le programme, ils ont rĂ©vĂ©lĂ© quâils avaient besoin de la comprĂ©hension, des conseils et du soutien des membres de la famille, des camarades de classe, des enseignants et des gens de l'industrie. De plus, ils avaient besoin de plus de temps pour explorer, expĂ©rimenter et travailler sur des tĂąches rĂ©pĂ©titives. Par ailleurs, trouver un Ă©quilibre entre la vie familiale et l'Ă©cole reprĂ©sentait un trĂšs grand dĂ©fi pour les femmes alors quâil semblait en ĂȘtre un pour quelques hommes seulement principalement ceux qui avaient des familles ou qui travaillaient de longues heures. Les participantes estiment qu'il existe toujours une attente sociale et culturelle pour qu'elles continuent Ă accomplir leurs tĂąches en dehors du travail scolaire, ce qui reprĂ©sente un dĂ©savantage certain pour elles. En ce qui concerne la cinquiĂšme question de la recherche, presque tous les participants ont rĂ©vĂ©lĂ© que lâinformatique n'Ă©tait pas leur premiĂšre option avant de poursuivre dans ce programme. La majoritĂ© des Ă©tudiants possĂ©daient un intĂ©rĂȘt de base pour les mathĂ©matiques et pour les sciences ce qui les a aidĂ©s Ă dĂ©velopper leur amour pour les dĂ©fis et la rĂ©solution de problĂšmes. Les hommes et les femmes sont d'accord sur le fait que la pratique auto-initiĂ©e et la curiositĂ© d'apprendre sont la clĂ© de la rĂ©ussite. Dans la description de leur passion pour l'informatique, les mots
«passion» et «intĂ©rĂȘt de persĂ©vĂ©rer» n'ont jamais Ă©tĂ© soulevĂ©s par les participantes au cours de notre conversation, alors que cela reprĂ©sentait un thĂšme rĂ©current pour les hommes. Les femmes ont rĂ©vĂ©lĂ© quâelles manquaient toujours de confiance en elles- mĂȘmes et dans leurs capacitĂ©s et cela mĂȘme lorsqu'elles rĂ©ussissaient bien. Ce qui n'Ă©tait pas un problĂšme pour la plupart des homes. Cette recherche dĂ©montre que le manque de confiance en soi, lâabsence de connaissances prĂ©alables, le nombres de modĂšles fĂ©minins insuffisant, lâabsence de mentors en plus du manque de soutien de la famille, des enseignants et des camarades pendant leurs Ă©tudes sont des facteurs qui jouent tous un rĂŽle clĂ© dans le choix de lâinformatique pour les Ă©tudiantes. En outre, l'intĂ©rĂȘt pour les mathĂ©matiques et pour les sciences, l'amour de la rĂ©solution de problĂšmes et la persĂ©vĂ©rance pour gĂ©rer les dĂ©fis ont peut-ĂȘtre Ă©galement influencĂ© les dĂ©cisions des Ă©tudiants de poursuivre dans le domaine de lâinformatique. Un ensemble de stratĂ©gies d'apprentissage Ă©prouvĂ©es et rĂ©ussies ont Ă©tĂ© partagĂ©es, incluant la patience, l'application de soi par la pratique rĂ©pĂ©titive, la dĂ©brouillardise et le travail sur un projet collaboratif pratique, tous combinĂ©s semblaient paver la voie Ă leur succĂšs. L'Ă©tude comprend un ensemble de recommandations pour aider Ă encourager plus de femmes Ă sâimpliquer davantage dans le domaine de lâinformatique
The obstacles to using technologies in primary schools to help students with mathematics difficulties in the Kingdom of Saudi Arabia
Despite the potential positive effects of using technology with students who have difficulties in mathematics in the Kingdom of Saudi Arabia and the great efforts made by the Saudi Government to improve the education system of the nation, which has included a continuous rise in the educational budget, there still remain some obstacles for some teachers when using technology, and while some of these teachers overcome these barriers, others do not succeed in this the challenge. This study investigated the barriers that teachers face when using technology in their classroom in primary schools, and why some overcame obstacles while others did not. Semi-structured interviews and observations were used for the purpose of this research, which were undertaken with three mathematics teachers from school A which used technology, and the other three from school B, which did not use technology. The researcher observed each teacher 45 times separately, 45 minutes each time, over a period of three months. The three teachers in school A were observed during the first 45 days, and the other three were observed for another 45 days. The researcher found from the interviewsâ responses of all six teachers and the consequent observations, that the head teacherâs support was the main reason behind their decision to overcome or not overcome the obstacles they face when using technology to help students with difficulties in mathematics. The principals of both schools played a crucial role in managing the challenges they faced with technology. This became evident when the head master of school A helped the teachers in overcoming the obstacles they faced when using technology by training teachers and through technical support, which reflected positively on teaching and learning mathematics, leading to a continued and enthusiastic use of technology. On the other hand, the head teacher in school B did not help or support his teachers in providing technology in school, nor help with overcoming the challenges they faced with technology, which reflected negatively on their enthusiasm to continue to overcome barriers such as the provision of technology in the school, and the lack of training and technical support, in spite of their beliefs that the technology has a positive impact on teaching and in the learning of students who have difficulties in mathematics. This study concludes with recommendations regarding future research in this area
A tale of two arteries: dual posterior cerebral arteries with vascular bridges. A possible protective pattern?
Stroke is a common morbidity and a frequent cause of disability and even death. The impact of cerebrovascular events is dictated by the brain region involved and can be complicated by anatomical variations. One of the most common variations impacting the cerebral vasculature is the presence of a foetal posterior cerebral artery. This vessel arises from the internal carotid artery instead of the basilar artery and is often associated with more extensive injury in cerebrovascular events. Herein, we report the case of a 60-year-old male who had numerous arterial abnormalities, including a kink and a coil of the left internal carotid, two posterior communicating arteries on the right and two posterior cerebral arteries (PCA) on the left, one arising from the internal carotid (foetal PCA) and one from the basilar. The foetal PCA supplied the thalamus, splenium of the corpus callosum and primary visual cortex. The basilar PCA supplied the midbrain and parts of the occipital lobe. These PCA were connected to each other by a vascular bridge and the foetal PCA was connected to the middle cerebral artery by an additional vascular bridge. This vascular pattern would appear to provide collateral support around blockages in the internal carotid and main stem middle and PCA
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