917 research outputs found

    Intelligent Self-Repairable Web Wrappers

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    The amount of information available on the Web grows at an incredible high rate. Systems and procedures devised to extract these data from Web sources already exist, and different approaches and techniques have been investigated during the last years. On the one hand, reliable solutions should provide robust algorithms of Web data mining which could automatically face possible malfunctioning or failures. On the other, in literature there is a lack of solutions about the maintenance of these systems. Procedures that extract Web data may be strictly interconnected with the structure of the data source itself; thus, malfunctioning or acquisition of corrupted data could be caused, for example, by structural modifications of data sources brought by their owners. Nowadays, verification of data integrity and maintenance are mostly manually managed, in order to ensure that these systems work correctly and reliably. In this paper we propose a novel approach to create procedures able to extract data from Web sources -- the so called Web wrappers -- which can face possible malfunctioning caused by modifications of the structure of the data source, and can automatically repair themselves.\u

    Faster Approximate String Matching for Short Patterns

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    We study the classical approximate string matching problem, that is, given strings PP and QQ and an error threshold kk, find all ending positions of substrings of QQ whose edit distance to PP is at most kk. Let PP and QQ have lengths mm and nn, respectively. On a standard unit-cost word RAM with word size wlognw \geq \log n we present an algorithm using time O(nkmin(log2mlogn,log2mlogww)+n) O(nk \cdot \min(\frac{\log^2 m}{\log n},\frac{\log^2 m\log w}{w}) + n) When PP is short, namely, m=2o(logn)m = 2^{o(\sqrt{\log n})} or m=2o(w/logw)m = 2^{o(\sqrt{w/\log w})} this improves the previously best known time bounds for the problem. The result is achieved using a novel implementation of the Landau-Vishkin algorithm based on tabulation and word-level parallelism.Comment: To appear in Theory of Computing System

    Dictionary Matching with One Gap

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    The dictionary matching with gaps problem is to preprocess a dictionary DD of dd gapped patterns P1,,PdP_1,\ldots,P_d over alphabet Σ\Sigma, where each gapped pattern PiP_i is a sequence of subpatterns separated by bounded sequences of don't cares. Then, given a query text TT of length nn over alphabet Σ\Sigma, the goal is to output all locations in TT in which a pattern PiDP_i\in D, 1id1\leq i\leq d, ends. There is a renewed current interest in the gapped matching problem stemming from cyber security. In this paper we solve the problem where all patterns in the dictionary have one gap with at least α\alpha and at most β\beta don't cares, where α\alpha and β\beta are given parameters. Specifically, we show that the dictionary matching with a single gap problem can be solved in either O(dlogd+D)O(d\log d + |D|) time and O(dlogεd+D)O(d\log^{\varepsilon} d + |D|) space, and query time O(n(βα)loglogdlog2min{d,logD}+occ)O(n(\beta -\alpha )\log\log d \log ^2 \min \{ d, \log |D| \} + occ), where occocc is the number of patterns found, or preprocessing time and space: O(d2+D)O(d^2 + |D|), and query time O(n(βα)+occ)O(n(\beta -\alpha ) + occ), where occocc is the number of patterns found. As far as we know, this is the best solution for this setting of the problem, where many overlaps may exist in the dictionary.Comment: A preliminary version was published at CPM 201

    Candida Arteritis in Patients Who Have Not Received Organ Transplants: Case Report and Review of the Literature

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    Fungal arteritis is a rare entity, associated with significant morbidity and mortality, that typically involves graft arteries in solid organ transplant recipients. Here, we report the first case of Candida carotid arteritis and review 22 other cases of Candida arteritis reported since 1966 in patients who have not received transplants. Most patients had serious underlying conditions. All cases were anatomically characterized by pseudoaneurysm formation. Patients presented with fever (n=17), local pain (n=13), and an expanding pulsatile mass (n=4), with subsequent rupture and hemorrhage (n=7). Evidence of Candida colonization or infection was present in 15 patients before arteritis occurred. Treatment typically included a combined surgical and antifungal approach. The outcome was favorable in 11 patients, but follow-up was limited. A high index of suspicion, early diagnosis, and prompt antifungal and surgical treatment seem crucial to efforts to avoid life-threatening arterial rupture and hemorrhag

    The Tree Inclusion Problem: In Linear Space and Faster

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    Given two rooted, ordered, and labeled trees PP and TT the tree inclusion problem is to determine if PP can be obtained from TT by deleting nodes in TT. This problem has recently been recognized as an important query primitive in XML databases. Kilpel\"ainen and Mannila [\emph{SIAM J. Comput. 1995}] presented the first polynomial time algorithm using quadratic time and space. Since then several improved results have been obtained for special cases when PP and TT have a small number of leaves or small depth. However, in the worst case these algorithms still use quadratic time and space. Let nSn_S, lSl_S, and dSd_S denote the number of nodes, the number of leaves, and the %maximum depth of a tree S{P,T}S \in \{P, T\}. In this paper we show that the tree inclusion problem can be solved in space O(nT)O(n_T) and time: O(\min(l_Pn_T, l_Pl_T\log \log n_T + n_T, \frac{n_Pn_T}{\log n_T} + n_{T}\log n_{T})). This improves or matches the best known time complexities while using only linear space instead of quadratic. This is particularly important in practical applications, such as XML databases, where the space is likely to be a bottleneck.Comment: Minor updates from last tim

    Reconstructing past terrace fields in the Pyrenees: Insights into land management and settlement from the Bronze Age to the Early Modern era at Vilalta (1650 masl, Cerdagne, France)

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    © Trustees of Boston University 2015. The building of a solar power station at Thémis, at 1650 masl on the south-facing slope of the Carlit massif in the eastern Pyrenees, led to an archaeological evaluation from April-June 2009. This evaluation covered a surface of 10 ha that included a medieval village as well as the surrounding agricultural land in terraces. Non-destructive archaeological methods were used for the village. A detailed study of the 6 ha of terraces began with a fieldwalking survey, mapping every visible feature, followed by systematic trial trenches. Fifty-five trenches, 11 in the village and 44 in the fields, were opened. The stratigraphies were then compared with a series of 22 radiocarbon dates and eight relative dates provided by ceramic typologies. This combination of surface and buried evidence supported our preliminary hypothesis about the dynamics of the slope. The results suggest the existence of agrarian features beginning in the Bronze Age and reveal that the field patterns were frequently transformed, both in the Medieval and Early Modern periods. The transformations in the terrace fields after the village was abandoned are as interesting as those during occupation because, contrary to the idea of a fixed, unchanging landscape after the end of the Middle Ages, they challenge the idea that mountain zones are marginal spaces by nature, or were marginalized later.Peer Reviewe

    Recommended care for young people (15-19 years) after suicide attempts in certain European countries

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    Abstract Data on recommended care for young people aged 15±19 years after attempted suicide from nine European research centres dur- ing the period 1989±1992 were ana- lysed in terms of gender, history of previous suicide attempt and meth- ods used. Altogether 438 suicide attempts made by 353 boys and 1,102 suicide attempts made by 941 girls were included. Analyses of the total data from all centres showed that young people with a history of previous suicide attempt and those using violent methods had signi®- cantly higher chance of being rec- ommended aftercare than ®rst-time attempters or those choosing self- poisoning. There were no signi®cant di erences of being recommended care between genders. Logistic re- gression analyses of the material were performed and the results were similar. Both having previous at- tempted suicide (odds ratio 2.0, 95% CI 1.53±2.61) and using ``hard'' methods (odds ratio 1.71, 95% CI 1.49±1.96) were signi®cantly associ- ated with increased possibility of being recommended aftercare. When individual centres were analysed, large disparities of recommended care after suicide attempts were found and there were no uniform criteria of recommending care for young suicide attempters in Europe. Key words Young people ± attempted suicide ± method ± recommended car

    Tie-Dye Attires Of Borno Kanuri People As Element of Cultural Identity In Postcolonial Nigeria

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    The sustenance and continuity of indigenous cultural identity has been a major concern and pursuit for post-colonial Africa. Decolonization, revival, and sustenance of national and ethnic identities are explored through the components of culture. Africans, including Nigerians, are greatly influenced by culture in their daily living, especially costumes. Nigerian cultural attires vary among ethnic groups and the peculiarity is relevant in identification, communication and association. This study examined the indigenous attire of the Kanuri people of Borno State in Nigeria, to evaluate the function of cultural dress in the decolonization process and identification of peoples in a globalized world. Textiles made from the tie-dye resist technique, in specific colors, have been adopted by the Kanuri as their peculiar traditional dress. The study purposively selected the female Kanuri Dongashou, used for wedding eve celebrations (Wushe-Wushe). Observational schedule, photographic documentation, and non-formal structured interviews were the instruments used during fieldwork to collect primary data. From results, the Kanuri people have established an identity through their cultural attires not only in northern Nigeria but globally. The survival and acceptability of the attires as a cultural factor had been possible due to the simplicity of the tie-dye technique, availability of cost-efficient materials, general affordability of the attires, and skills-transfer through generations. Keywords: Attire, Cultural Identity, Kanuri, Postcolonial Nigeria, Tie and Dye

    Many-body theory of pump-probe spectra for highly excited semiconductors

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    We present a unified theory for pump-probe spectra in highly excited semiconductors, which is applicable throughout the whole density regime including the high-density electron-hole BCS state and the low-density excitonic Bose-Einstein condensate (BEC). The analysis is based on the BCS-like pairing theory combined with the Bethe-Salpeter (BS) equation, which first enables us to incorporate the state-filling effect, the band-gap renormalization and the strong/weak electron-hole pair correlations in a unified manner. We show that the electron-hole BCS state is distinctly stabilized by the intense pump-light, and this result strongly suggests that the macroscopic quantum state can be observed under the strong photoexcitation. The calculated spectra considerably deviate from results given by the BCS-like mean field theory and the simple BS equation without electron-hole pair correlation especially in the intermediate density states between the electron-hole BCS state and the excitonic BEC state. In particular, we find the sharp stimulated emission and absorption lines which originate from the optical transition accompanied by the collective phase fluctuation mode in the electron-hole BCS state. From the pump-probe spectral viewpoint, we show that this fluctuation mode changes to the exciton mode with decreasing carrier densityComment: RevTeX 11 pages, 10 figures. To appear in Phys.Rev.B1

    Epidemiology of methicillin-resistant Staphylococcus aureus: results of a nation-wide survey in Switzerland.

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    To assess the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in Switzerland. One-year national survey of all MRSA cases detected in a large sample of Swiss healthcare institutions (HCI). Analysis of epidemiological and molecular typing data (PFGE) of MRSA strains. During 1997, 385 cases of MRSA were recorded in the 5 university hospitals, in 33 acute care community hospitals, and 14 rehabilitation or long-term care institutions. Half of the cases were found at the University of Geneva Hospitals where MRSA was already known to be endemic (41.1 cases/10,000 admissions). The remaining cases (200) were distributed throughout Switzerland. The highest rates (>100 cases/10,000 admissions) were reported from non-acute care institutions. Rates ranged from 3.3 to 41.1 cases/10,000 admissions for university hospitals (mean 15.5); 0.67 to 90.4 for community hospitals (mean 4.8), and 28.2 to 315 for non-acute care institutions reporting MRSA (mean 85.7). Forty percent of MRSA patients were infected, while 60% were only colonised. The leading infection sites were skin and soft tissue (21%), surgical site (15%), and the urinary tract (26%). Whereas in Eastern Swiss HCI most MRSA cases occurred in acute care hospitals (n = 47, 98%), rehabilitation and long-term care institutions accounted for an important number of the identified cases (n = 107, 38%) in Western Switzerland. Low rates of MRSA were still observed in Swiss HCI, despite one outlying acute care centre with endemic MRSA and some nonacute care institutions with epidemic MRSA. Rehabilitation and long-term care institutions contributed to a substantial proportion of cases in Western Switzerland and may constitute a significant reservoir. Overall, a national approach to surveillance and control of MRSA is mandatory in order to preserve a still favourable situation, and to decrease the risk of epidemic MRSA dissemination
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