Showing papers by "Jordan University of Science and Technology published in 2000"

Text Classification from Labeled and Unlabeled Documents using EM

Abstract: This paper shows that the accuracy of learned text classifiers can be improved by augmenting a small number of labeled training documents with a large pool of unlabeled documents. This is important because in many text classification problems obtaining training labels is expensive, while large quantities of unlabeled documents are readily available. We introduce an algorithm for learning from labeled and unlabeled documents based on the combination of Expectation-Maximization (EM) and a naive Bayes classifier. The algorithm first trains a classifier using the available labeled documents, and probabilistically labels the unlabeled documents. It then trains a new classifier using the labels for all the documents, and iterates to convergence. This basic EM procedure works well when the data conform to the generative assumptions of the model. However these assumptions are often violated in practice, and poor performance can result. We present two extensions to the algorithm that improve classification accuracy under these conditions: (1) a weighting factor to modulate the contribution of the unlabeled data, and (2) the use of multiple mixture components per class. Experimental results, obtained using text from three different real-world tasks, show that the use of unlabeled data reduces classification error by up to 30%.

Soil Thermal Conductivity Effects of Density, Moisture, Salt Concentration, and Organic Matter

Abstract: The thermal conductivity of soil under a given set of conditions is most important as it relates to a soil's microclimate. The early growth and development of a crop may be determined to a large extent by microclimate. The effect of bulk density, moisture content, salt concentration, and organic matter on the thermal conductivity of some sieved and repacked Jordanian soils was investigated through laboratory studies. These laboratory experiments used the single probe method to determine thermal conductivity. The soils used were classified as sand, sandy loam, loam, and clay loam. The two salts used were NaCl and CaCl 2 , while addition of peat moss was used to increase the organic matter content, For the soils studied, thermal conductivity increased with increasing soil density and moisture content. Thermal conductivity ranged from 0.58 to 1.94 for sand, from 0.19 to 1.12 for sandy loam, from 0.29 to 0.76 for loam, and from 0.36 to 0.69 W/m K for clay loam at densities from 1.23 to 1.59 g cm 3 and water contents from 1.4 to 21.2%, The results also show that an increase in the amount of added salts at given moisture content (volumetric solution contents θ ranged from 0.03-0.12 m 3 m -3 for the sand and from 0.09-0.30 m 3 m 3 for the clay loam) decreased thermal conductivity. Increasing the percentage of soil organic matter decreased thermal conductivity, Finally, il was found that the sand had higher values of thermal conductivity than the clay loam for the same salt type and concentrations.

Multi-document summarization by sentence extraction

Abstract: This paper discusses a text extraction approach to multi-document summarization that builds on single-document summarization methods by using additional, available information about the document set as a whole and the relationships between the documents. Multi-document summarization differs from single in that the issues of compression, speed, redundancy and passage selection are critical in the formation of useful summaries. Our approach addresses these issues by using domain-independent techniques based mainly on fast, statistical processing, a metric for reducing redundancy and maximizing diversity in the selected passages, and a modular framework to allow easy parameterization for different genres, corpora characteristics and user requirements.

Growth of mycorrhizal tomato and mineral acquisition under salt stress.

Abstract: High salt levels in soil and water can limit agricultural production and land development in arid and semiarid regions. Arbuscular mycorrhizal fungi (AMF) have been shown to decrease plant yield losses in saline soils. The objective of this study was to examine the growth and mineral acquisition responses of greenhouse-grown tomato to colonization by the AMF Glomus mosseae [(Nicol. And Gerd.) Gerd. and Trappe] under varied levels of salt. NaCl was added to soil in the irrigation water to give an ECe of 1.4 (control), 4.7 (medium) and 7.4 dS m–1 (high salt stress). Plants were grown in a sterilized, low P (silty clay) soil-sand mix. Mycorrhizal colonization was higher in the control than in saline soil conditions. Shoot and root dry matter yields and leaf area were higher in mycorrhizal than in nonmycorrhizal plants. Total accumulation of P, Zn, Cu, and Fe was higher in mycorrhizal than in nonmycorrhizal plants under both control and medium salt stress conditions. Shoot Na concentrations were lower in mycorrhizal than in nonmycorrhizal plants grown under saline soil conditions. The improved growth and nutrient acquisition in tomato demonstrate the potential of AMF colonization for protecting plants against salt stress in arid and semiarid areas.

High strength concrete containing natural pozzolan and silica fume

Abstract: Various combinations of a local natural pozzolan and silica fume were used to produce workable high to very high strength mortars and concretes with a compressive strength in the range of 69–110 MPa. The mixtures were tested for workability, density, compressive strength, splitting tensile strength, and modulus of elasticity. The results of this study suggest that certain natural pozzolan–silica fume combinations can improve the compressive and splitting tensile strengths, workability, and elastic modulus of concretes, more than natural pozzolan and silica fume alone. Furthermore, the use of silica fume at 15% of the weight of cement was able to produce relatively the highest strength increase in the presence of about 15% pozzolan than without pozzolan. This study recommends the use of natural pozzolan in combination with silica fume in the production of high strength concrete, and for providing technical and economical advantages in specific local uses in the concrete industry.

Headline generation based on statistical translation

Abstract: Extractive summarization techniques cannot generate document summaries shorter than a single sentence, something that is often required. An ideal summarization system would understand each document and generate an appropriate summary directly from the results of that understanding. A more practical approach to this problem results in the use of an approximation: viewing summarization as a problem analogous to statistical machine translation. The issue then becomes one of generating a target document in a more concise language from a source document in a more verbose language. This paper presents results on experiments using this approach, in which statistical models of the term selection and term ordering are jointly applied to produce summaries in a style learned from a training corpus.

OCELOT: a system for summarizing Web pages

Abstract: We introduce OCELOT, a prototype system for automatically generating the “gist” of a web page by summarizing it. Although most text summarization research to date has focused on the task of news articles, web pages are quite different in both structure and content. Instead of coherent text with a well-defined discourse structure, they are more often likely to be a chaotic jumble of phrases, links, graphics and formatting commands. Such text provides little foothold for extractive summarization techniques, which attempt to generate a summary of a document by excerpting a contiguous, coherent span of text from it. This paper builds upon recent work in non-extractive summarization, producing the gist of a web page by “translating” it into a more concise representation rather than attempting to extract a text span verbatim. OCELOT uses probabilistic models to guide it in selecting and ordering words into a gist. This paper describes a technique for learning these models automatically from a collection of human-summarized web pages.

Growth, water use efficiency, and sodium and potassium acquisition by tomato cultivars grown under salt stress.

Abstract: Three cultivars of tomato (Lycopersicon esculentum Mill., cvs. Sera, 898, Rohaba) were grown under different levels of NaCl in nutrient solution to determine effects of salt stress on shoot and root dry matter (DM), plant height, water use efficiency (WUE, g DM kg‐1 water evapotranspired), shoot sodium (Na) and potassium (K) concentrations, and K versus Na selectivity (SK,Na). Increasing NaCl concentration in nutrient solution adversely affected shoot and root DM, plant height, WUE, K concentration, and K/Na ratio of all cultivars. Shoot Na concentrations increased with increasing NaCl concentration in the nutrient solution. Although increasing salt concentration in the solution adversely affected growth of all cultivars, the cultivar Sera had the highest shoot and root DM than the other two cultivars (898 and Rohaba). Shoot and root DM of cultivar 898 was most affected by salt, while cultivar Rohaba had an intermediate salt sensitivity. The cultivar Sera generally had higher WUE values, shoot K ...

Homozygosity Mapping Identifies an Additional Locus for Wolfram Syndrome on Chromosome 4q

Abstract: Wolfram syndrome, which is sometimes referred to as "DIDMOAD" (diabetes insipidus, diabetes mellitus, optic atrophy, and deafness), is an autosomal recessive neurodegenerative disorder for which only insulin-dependent diabetes mellitus and optic atrophy are necessary to make the diagnosis. Researchers have mapped Wolfram syndrome to chromosome 4p16.1, and, recently, a gene encoding a putative transmembrane protein has been cloned and mutations have been identified in patients. To pursue the possibility of locus heterogeneity, 16 patients from four different families were recruited. These patients, who have the Wolfram syndrome phenotype, also have additional features that have not previously been reported. There is an absence of diabetes insipidus in all affected family members. In addition, several patients have profound upper gastrointestinal ulceration and bleeding. With the use of three microsatellite markers (D4S432, D4S3023, and D4S2366) reported to be linked to the chromosome 4p16.1 locus, we significantly excluded linkage in three of the four families. The two affected individuals in one family showed homozygosity for all three markers from the region of linkage on chromosome 4p16.1. For the other three families, genetic heterogeneity for Wolfram syndrome was verified by demonstration of linkage to chromosome 4q22-24. In conclusion, we report the unique clinical findings and linkage-analysis results of 16 patients with Wolfram syndrome and provide further evidence for the genetic heterogeneity of this disorder. We also provide data on a new locus that plays a role in the etiology of insulin-dependent diabetes mellitus.

Constrained motion control using vector potential fields

Abstract: Discusses the generation of a control signal that would instruct the actuators of a robotics manipulator to drive motion along a safe and well-behaved path to a desired target. The proposed concept of navigation control along with the tools necessary for its construction achieve this goal. The most significant tool is the artificial vector potential field which shows a better ability to steer motion than does a scalar potential field. The synthesis procedure emphasizes flexibility so that the effort needed to modify the control is commensurate with the change in the geometry of the workspace. Theoretical development along with simulation results are provided.

Fournier's gangrene: Changing face of the disease

Abstract: PURPOSE: Our experience with ten cases of Fournier's gangrene prompted us to review the related literature to highlight the current status of the disease. METHODS: Data from ten patients with the diagnosis of Fournier's gangrene treated at our center from January 1997 until December 1998 were analyzed. These patients were treated by aggressive resuscitation, triple antibiotics, and urgent surgery. The English-language medical literature for the past 30 years was reviewed. RESULTS: The epidemiologic features of our patients were similar to those reported in other recent studies. Mortality rate was 20 percent. Currently, the disease affects both genders and a wide range of ages, has a more insidious onset than in the past, and is not idiopathic. Associated systemic disorders (diabetes, alcoholism, and immunosuppression) are common. Perianal infection is the commonest cause and is associated with more moribund features. CONCLUSION: The epidemiology of Fournier's gangrene is changing from its original description. Population aging worldwide—as a result of improving health care—and therefore the increasing prevalence of associated medical disorders may explain these changes. These factors may also explain the consistently high mortality rate during more recent years, masking any survival benefits from improved medical care. Better understanding of the pathophysiology has reduced the ratio of idiopathic cases to a minimum.

Localisation of a gene for prepubertal periodontitis to chromosome 11q14 and identification of a cathepsin C gene mutation

Abstract: Prepubertal periodontitis (PPP) is a rare and rapidly progressive disease of young children that results in destruction of the periodontal support of the primary dentition. The condition may occur as part of a recognised syndrome or may occur as an isolated finding. Both autosomal dominant and recessive forms of Mendelian transmission have been reported for PPP. We report a consanguineous Jordanian family with four members aVected by PPP in two nuclear sibships. The parents of the aVected subjects are first cousins. We have localised a gene of major eVect for PPP in this kindred (Zmax=3.55 for D11S901 at =0.00) to a 14 cM genetic interval on chromosome 11q14 flanked by D11S916 and D11S1367. This PPP candidate interval overlaps the region of chromosome 11q14 that contains the cathepsin C gene responsible for Papillon-Lefevre and Haim-Munk syndromes. Sequence analysis of the cathepsin C gene from PPP aVected subjects from this Jordanian family indicated that all were homozygous for a missense mutation (1040A→G) that changes a tyrosine to a cysteine. All four parents were heterozygous carriers of this Tyr347Cys cathepsin C mutation. None of the family members who were heterozygous carriers for this mutation showed any clinical findings of PPP. None of the 50 controls tested were found to have this Tyr347Cys mutation. This is the first reported gene mutation for nonsyndromic periodontitis and shows that non-syndromic PPP is an allelic variant of the type IV palmoplantar ectodermal dysplasias. (J Med Genet 2000;37:95‐101)

Query-relevant summarization using FAQs

Abstract: This paper introduces a statistical model for query-relevant summarization: succinctly characterizing the relevance of a document to a query. Learning parameter values for the proposed model requires a large collection of summarized documents, which we do not have, but as a proxy, we use a collection of FAQ (frequently-asked question) documents. Taking a learning approach enables a principled, quantitative evaluation of the proposed system, and the results of some initial experiments---on a collection of Usenet FAQs and on a FAQ-like set of customer-submitted questions to several large retail companies---suggest the plausibility of learning for summarization.

Etiology and diagnosis of tooth wear: a literature review and presentation of selected cases.

Abstract: PURPOSE This article presents an overview of etiologies associated with tooth wear. MATERIALS AND METHODS Specific types of wear based on clinical findings and patient history are described. RESULTS The occurrence and pattern of tooth wear are related to cultural, dietary, occupational, and geographic factors. Examples of tooth wear related to these factors with regional specificity are presented. CONCLUSION The dental practitioner should recognize the characteristic signs of tooth wear, as they may be the first to discuss the problem with the patient. Management should be based on accurate diagnosis.

Symptoms of anxiety and depression among adolescents with seizures in Irbid, Northern Jordan.

Abstract: In Jordan, individuals with epilepsy commonly attend neuropsychiatric clinics. The objective of this study was to assess the psychosocial outcome of epilepsy among adolescents. The study included 101 epileptic adolescents who attended the neurology clinic at the Princess Basma Teaching Hospital in Northern Jordan and 101 non-epileptic controls. Sociodemographic characteristics and all relevant clinical data were collected through interviewing the cases and controls. Identification of the symptoms of anxiety and depression was made according to DSM-IV criteria. The patients were age and sex matched with the controls. The controls had achieved a significantly better education (> 12 years education) than the patients with epilepsy. The adolescents with epilepsy were also shown to be disadvantaged in their living circumstances. Some of them were dependent on their parents in some daily physical activities, such as bathing, which might be a sign of overprotection by their parents. Those with epilepsy had a significantly higher tendency to develop symptoms of anxiety and depression than the control group. Moreover these psychiatric symptoms, especially anxiety symptoms, were more likely to happen when seizures had not been properly medically controlled. Overprotective parental behaviour towards their ill children could also delay their psychosocial maturation. Therefore, counselling of patients and parents about epilepsy is an important factor in the control of seizures and their sequelae.

Magnetic and structural properties of SmCo7-xCux alloys

Abstract: We report the structural and magnetic properties of SmCo7−xCux, where x=0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.7. X-ray diffraction shows that these alloys from the disordered hexagonal TbCu7-type structure. For large values of x(x⩾0.8) the hexagonal TbCu7-type structure cannot be formed. X-ray diffraction on magnetically aligned samples show that these samples have uniaxial anisotropy. The lattice parameters (a and c) are dependent on the Cu concentration, and the unit cell volume is found to increase with x. The saturation magnetization decreases with x at both room temperature and 25 K. The Curie temperature increases with x for small values of x while it decreases with x for large values of x. A maximum value of TC=852 °C is found in these alloys.

Memory-based face recognition for visitor identification

Abstract: We show that a simple, memory-based technique for appearance-based face recognition, motivated by the real-world task of visitor identification, can outperform more sophisticated algorithms that use principal components analysis (PCA) and neural networks. This technique is closely related to correlation templates; however, we show that the use of novel similarity measures greatly improves performance. We also show that augmenting the memory base with additional, synthetic face images results in further improvements in performance. Results of extensive empirical testing on two standard face recognition datasets are presented, and direct comparisons with published work show that our algorithm achieves comparable (or superior) results. Our system is incorporated into an automated visitor identification system that has been operating successfully in an outdoor environment since January 1999.

Risk indicators associated with tooth loss in Jordanian adults.

Abstract: –Objectives: The purpose of this study was to evaluate the risk indicators of tooth loss in Jordanian adults. Methods: A sample of 509 Jordanian adults was randomly selected. The subjects were interviewed regarding demographics, social economic status, smoking habits, and oral hygiene practices and then clinically examined by a single examiner. Multiple regression analysis was performed to estimate the simultaneous impact of risk indicators on tooth loss. Results: The subjects’ mean age was 42.6 years with an average of 20.9 teeth remaining per person. The overall educational level of the subjects was low. More than 40% reported not brushing their teeth regularly and 56% had had no professional teeth cleaning during the last year. Monthly family income averaged JOD 231, and about a third of the subjects were smokers. The mean number of remaining teeth decreased significantly with age. Smokers, those who brushed irregularly, and those who had not had professional teeth cleaning in the last year had significantly fewer remaining teeth. Men also had significantly fewer remaining teeth. Education and income were also significantly associated with the number of remaining teeth. Age, income, brushing, prophylaxis, and gender collectively explain 75.1% of the variance in the number of remaining teeth. Conclusion: Modification of non-disease independent factors could reduce tooth loss and improve oral health in Jordanians.