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Results for “Classification Algorithms”

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PubMed2000

[Study on statistical method of distribution for erythrocyte morphological features by computerized image processing].

This study sought to develop a new statistic method for the semiautomatic analysis and classification of erythrocyte morphology based on the morphological features and shape analysis of erythrocytes by computer image processing. Shape factor as the description of the erythrocyte morphological features was used for the shape classification of erythrocytes. And the models and algorithms of erythrocytes image segmentation, cell body shape recognition and measure can be implemented through the VC++. The present method can efficiently and semi-automatically provide the statistical analysis of erythrocyte morphology, and can give the distribution of erythrocyte morphological features. The result showed that there was a significant difference between the distribution curves of the normal erythrocyte morphology (one apex) and hemolytic anemia's (two apices). By this way, it can be obtained the proportion data of different cell bodies' shapes. This method could provide some information for the study and diagnosis of the diseases (e.g. hemolytic anemia, pre-leukemia) related to erythrocyte morphology.

Algorithms↗

PubMedDate not supplied

[Surgical strategy of treatment of severe and extremely severe eye burns. I].

A total of 112 patients with severe and extremely severe burns of the eyes were treated. The author proves that one of the main causes of unsatisfactory results is the absence of clearly defined criteria for the choice of surgical strategy during the early period. Based on the classification of interventions, the author suggests an algorithm of early surgical treatment of eye burns.

Corneal Transplantation↗

PubMed1990

[Large bowel cancer: prognostic factors, surgical treatments and their results].

Although the classification proposed by Dukes has been repeatedly modified, causing unnecessary confusion, his original concept remains unrefuted; cancer penetration through the bowel wall and lymph node metastasis are two major prognostic factors, of which nodal metastasis represents a more advanced stage. However, the results of our exhaustive computer analyses did not support this concept, and better classifications may be developed using our computer algorithm, enabling us to refine the indication for extensive surgery or limited resection. There are two trends of surgical treatment in Japan. One is an attempt to extend the area of resection including the paraaortic and parailiac nodes, and also iliac vessels. Patients treated by this method show a higher survival rate if compared with historical controls in Japan. However, extensive surgery of the rectum is associated with poor quality of life with bladder and anal dysfunctions as well as sexual impotence. The other trend is to limit the extent of resection and minimize the functional defect. The organs thus saved include the sphincter and autonomic nerves. The results are almost comparable with those of more radical surgery. With aggressive re-resection of recurrent tumors in the liver, lungs, lymph nodes and local areas, the number of long-term survivors is now increasing who would otherwise have died.

Colorectal Neoplasms↗

PubMedDate not supplied

[Integrated lists of taxonomic evaluation criteria: LICET-S and LICET-D].

LICET-S and LICET-D are diagnostic instruments containing all diagnostic criteria for two major groups of disorders. LICET-S assembles the criteria proposed for non-affective psychoses in 9 different systems. LICET-D integrates the criteria defining the depressive categories listed in 7 different systems. Initially constructed to elaborate empirical criteria for specific categories pertaining to traditional French nosology, the two lists also permit to formulate diagnostic decisions according to 9 respectively 7 classification systems, on the basis of the algorithms defining each of the systems under discussion. The authors present the rationale that led to the construction of the LICET-system. They describe the composition of the two lists and the guidelines for use of the system. They finally illustrate the utility of the instruments on the basis of results obtained in recent investigations.

Depressive Disorder↗

PubMed2006

Utilization of artificial neural networks and autoregressive modeling in diagnosing mitral valve stenosis.

This research is concentrated on the diagnosis of mitral heart valve stenosis through the analysis of Doppler Signals' AR power spectral density graphic with the help of ANN. Multilayer feedforward ANN trained with a Levenberg Marquart backpropagation algorithm was implemented in the MATLAB environment. Correct classification of 94% was achieved, whereas 4 false classifications have been observed for the test group of 68 subjects in total. The designed classification structure has about 97.3% sensitivity, 90.3% specifity and positive prediction is calculated to be 92.3%. The stated results show that the proposed method can make an effective interpretation.

Adult↗

PubMed2006

Stages of change algorithm for calcium intake by male college students.

Using a sample of college-aged men, we evaluated the validity of a staging algorithm for dairy calcium intake that had been previously validated in a sample of college women. College-aged men enrolled at a private university in the United States were randomly selected to participate. The sample consisted of 180 male participants. Self-reported calcium intake was measured using a 26-item food frequency questionnaire. Stages of change classifications were based on a four-question algorithm for dairy calcium intake and a three-item self-efficacy questionnaire. Significant differences were found between dairy/calcium intake levels between pre-contemplation, contemplation/preparation, and action/maintenance groups. Results also showed that 46% of participants were in the action/maintenance stage. There was a significant difference in self-efficacy between members of the pre-action and action stages. The study suggests that this stage of change algorithm for dairy calcium intake is valid for use in a male college student population.

Adolescent↗

PubMed1998

Potential implications of the integrated management of childhood illness (IMCI) for hospital referral and pharmaceutical usage in western Uganda.

The integrated management of childhood illness approach (IMCI) is currently being implemented by a number of countries worldwide. This is the second report from a study in western Uganda comparing the assessment and classification of disease by medical assistants using the IMCI algorithm with that of hospital-based general medical officers, who used their clinical judgement to assess and provide treatment. Treatment prescribed by the hospital medical officers was compared to that indicated by IMCI disease classifications. The study population comprised 1226 children aged 2-59 months. Medical assistants had some difficulty in completing the IMCI assessment, leading to incorrect classification of findings in 138 of 1086 completed forms (13%). If their classifications had been used to decide on hospital referral, 37 children who met IMCI criteria for referral would have been sent home. Consultations took on average 7.2 min, longer than usual for several African countries. Use of the IMCI guidelines would have referred 16.2% of children to hospital, compared with 22% referred by the medical officers. Use of IMCI could have reduced the cost of medication to US$0.17 per child compared to the treatment cost of US$0.82 as prescribed by medical officers. Medical officers prescribed both a greater number and a greater variety of drugs than indicated by the IMCI algorithm. Compared to the present management of sick children by medical officers at Kabarole district hospital, using the IMCI algorithm would bring major changes in pharmaceutical use and referral practices. However, there is concern about the difficulty medical assistants had in using it, and the potential for longer consultation times.

Algorithms↗

PubMed1989

Automated rule based graded analysis of ambulatory cassette EEGs.

We describe algorithms, developed on a PDP-11/73 microcomputer, which identify spikes/sharp waves (STs), spike-and-wave complexes (SSWs), artifacts and background activity in 4-channel ambulatory EEGs. The algorithms were trained using 40 database segments. Time domain/mimetic methods were used and semantic rules, based on morphology and multi-channel contextual information, were developed to mimic the principles used in visual interpretation. The likelihood of STs/SSWs being genuine was graded from 10 to 1. This approach avoids forced classification of each event as genuine ST/SSW or not. The algorithms were then evaluated using 60 independent segments. STs/SSWs graded greater than 7 had significantly higher probability (P less than 0.005) of being genuine than those graded less than or equal to 7. Less than 4% of STs/SSWs identified by both electroencephalographers were missed. None was distinct. All 113 artifacts resembling STs/WWs were graded less than or equal to 7. Classification of 969/1117 (86%) waves in the background matched that of one electroencephalographer. The algorithms can be extended to 8- or more-channel EEGs.

Algorithms↗

PubMed2002

Development and validation of a stages of change algorithm for calcium intake for college female students.

OBJECTIVES: The purpose of this study was to develop and validate a staging algorithm for calcium intake. METHODS: Three hundred seventy-six college-aged females at a private university were randomly selected to participate. After 8.5% of the data were omitted due to incomplete surveys, the sample consisted of 344 female participants. Calcium intake was measured as self-reported consumption with a 26-item food frequency questionnaire. Stages of change classifications were based on a four-item algorithm for calcium intake, and self-efficacy was measured with three items. RESULTS: Significant differences were found between calcium intake levels between precontemplation, contemplation/preparation and action/maintenance. Results also showed that 40% of the participants were in action/maintenance and were consuming the Dietary Reference Intake level of 1,000 mg of daily calcium. Participants in the action and maintenance stages had significantly higher self-efficacy than the preaction group. CONCLUSION: The study suggests that the stages of change algorithm may be used as an effective tool in assessing daily calcium intake among a college female population.

Adolescent↗

PubMed2001

[The diagnostic concept of acute infection of the shoulder joint].

INTRODUCTION: It is generally accepted that septic conditions of the shoulder often lead to an earnest situation with joint damage. Because of the low incidence of shoulder infections there are only a few cases reported in the literature. Therefore, unlike joint infections of the knee no diagnostic and therapeutic standard procedure is documented for the shoulder. MATERIALS AND METHODS: In a retrospective study the results of 15 patients with a surgical revision at the BG-Clinic-Bergmannsheil-Bochum between 1 January 1989 and 31 August 1999 after an infection of the shoulder joint were analyzed. We registered the following parameters: etiology, intervall until the first clinical symptoms, clinical signs, diagnostic procedure, intraoperative site (Gächter classification), and operative treatment. The diagnostic procedure followed an algorithm, including CRP-determination, ultrasound of the shoulder, ultrasound-guided aspiration and a Gram stain. If the result was positive, surgical joint revision followed. The infection stage was classified intraoperatively according to the criteria of the Gächter classification. Eight patients were reexamined after an average follow-up of 4.8 years. RESULTS: Fourteen infections followed injection. All patients demonstrated increasing CRP levels and a painful limited range of motion. In all Gram stains we detected bacterial organisms. The diagnosis of an acute infection according to the criteria of this diagnostic algorithm was verified intraoperatively in all 15 joints. Two patients with delayed admission died postoperatively due to septic multiorgan failure despite maximal treatment under intensive care conditions. CONCLUSION: If there are suspicious clinical symptoms after a typical anamnesis, we recommend an immediate diagnostic algorithm, including CRP determination, ultrasound of the shoulder, ultrasound-guided joint puncture and a Gram stain. If there is acute joint infection, time-consuming diagnostic procedures must be avoided because of the risk of secondary reduced joint mobility or life-threatening complications.

Acute Disease↗

PubMed1996

Allometric algorithms.

The aim of the present study is to emphasize the applicability and versatility of the allometric equation in the biological sciences. This equation (Y = a x Mb) was introduced by Huxley (1932) for intra- and interspecific comparisons of morphological, physiological and ecological variables (Y), when they are expressed as functions of body mass (M). The regression analysis of the experimental data, plotted in a double logarithmic scale, yields a straight line, which is equivalent to the logarithmic form of the above mentioned allometric equation [log Y = log(a) + (b) x log(M)]. Only the exponent (b) can be calculated a priori for a given function, based firstly on the corresponding dimensional analysis in accordance with the MLT-system of physics, and secondly on one of the theories of biological similarity, while parameter (a) is of empirical nature. A relevant feature of the allometric equations is that they can be treated algebraically to obtain allometric ratios, mass independent numbers (MIN), and even dimensionless numbers (M0L0T0), which are valid for all organisms pertaining to the same taxonomic classification.

Algorithms↗

PubMed2005

[Land cover classification in Xianghai Nature Reserve].

This paper discussed the application of Fuzzy ARTMAP neural network in land cover classification in Xianghai Nature Reserve. The structure and algorithm of Fuzzy ARTMAP neural network were described in detail, and an automatic adjustment method of vigilance parameter was put forward to solve the problem of searching the optimum value in the selection of vigilance parameter. The results showed that the automatic adjustment method could adjust network parameter automatically, and improve the running speed of network. In comparing with maximum likelihood classification method and traditional Fuzzy ARTMAP neural network, the Fuzzy ARTMAP neural network with the functioning of automatic adjustment depended less on samples and had higher accuracy, and thus, could effectively make the classification of TM image covering Xianghai Nature Reserve. It's shown from the classification that in the Xianghai Nature Reserve, farmland covered large area while grassland and marsh were facing degradation, and hence, corresponding countermeasures should be taken to improve the eco-environment of this Reserve.

Conservation of Natural Resources↗

PubMedDate not supplied

Efficient information theoretic strategies for classifier combination, feature extraction and performance evaluation in improving false positives and false negatives for spam e-mail filtering.

Spam emails are considered as a serious privacy-related violation, besides being a costly, unsolicited communication. Various spam filtering techniques have been so far proposed, mainly based on Naïve Bayesian algorithms. Other Machine Learning algorithms like Boosting trees, or Support Vector Machines (SVM) have already been used with success. However, the number of False Positives (FP) and False Negatives (FN) resulting through applying various spam e-mail filters still remains too high and the problem of spam e-mail categorization cannot be solved completely from a practical viewpoint. In this paper, we propose a novel approach for spam e-mail filtering based on efficient information theoretic techniques for integrating classifiers, for extracting improved features and for properly evaluating categorization accuracy in terms of FP and FN. The goal of the presented methodology is to empirically but explicitly minimize these FP and FN numbers by combining high-performance FP filters with high-performance FN filters emerging from a previous work of the authors [Zorkadis, V., Panayotou, M., & Karras, D. A. (2005). Improved spam e-mail filtering based on committee machines and information theoretic feature extraction. Proceedings of the International Joint Conference on Neural Networks, July 31-August 4, 2005, Montreal, Canada]. To this end, Random Committee-based filters along with ADTree-based ones are efficiently combined through information theory, respectively. The experiments conducted are of the most extensive ones so far in the literature, exploiting widely accepted benchmarking e-mail data sets and comparing the proposed methodology with the Naive Bayes spam filter as well as with the Boosting tree methodology, the classification via regression and other machine learning models. It is illustrated by means of novel information theoretic measures of FP & FN filtering performance that the proposed approach is very favorably compared to the other rival methods. Finally, it is found that the proposed information theoretic Boolean features present a remarkably high spam categorization performance.

Algorithms↗

PubMed2005

Application of supergeneralized matched filters to target classification.

The matched filter (MF) is the optimum linear operator for distinguishing between a fixed signal and noise, given the noise statistics. A generalized matched filter (GMF) is a linear filter that can handle the more difficult problem of a multiple-example signal set, and it reduces to a MF when the signal set has only one member. A supergeneralized matched filter (SGMF) is a set of GMFs and a procedure to combine their results nonlinearly to handle the multisignal problem even better. Obviously the SGMF contains the GMF as a special case. An algorithm for training SGMFs is presented, and it is shown that the algorithm performs quite well even for extremely difficult classification problems.

Journal Article↗

PubMed1984

[Potentials and limits of conventional differential diagnosis of the endometrium].

The reproducible identification of various histological types of the endometrium is of special interest for many reasons. The controversy in endometrial classification and terminology led us to study the algorithm of conventional endometrial diagnosing. This study is to examine the significance of historical morphologic parameters for differential diagnosis by semiquantitative or binary recording and computer-assisted evaluation. The results are based on cross-tables and cluster-analysis. The statistical test showed that most of the historical parameters were neither adequate for reclassification nor exclusion of historical typing of the endometrium. An objective and reproducible classification of endometrial changes by using binary parameters can only be achieved for specific histological types of normal endometrium and several types of hyperplastic endometrium. The dedifferentiated carcinoma is a diagnosis "per exclusionem ", since nearly all of the binary parameters cannot be analysed. The individual borderline lesions cannot be differentiated from each other by descriptive parameters. They cannot even be distinguished from the highly differentiated endometrial carcinomas. This kind of differential diagnosis is obviously not based on conventional formalistic criteria but on nonquantifiable empirical data. This might be a reason for the above mentioned controversy in endometrial diagnosis and terminology.

Diagnosis, Differential↗

PubMed1996

Multisolutional clustering and quantization algorithm (MCQ).

We have developed a novel clustering and quantization algorithm that allows the user to create multiple one-to-one correspondences between the actual data and its transformed (clustered and quantized) values, based on the user's hypothesis regarding the nature of the classification task. The types of problems for which the algorithm can be beneficial are discussed. We report experiments employing simulated and real data that suggest the proposed algorithm may be useful in neural network analysis of various phenomena in medicine and biology.

Algorithms↗

PubMed2004

QSAR and classification models of a novel series of COX-2 selective inhibitors: 1,5-diarylimidazoles based on support vector machines.

The support vector machine, which is a novel algorithm from the machine learning community, was used to develop quantitation and classification models which can be used as a potential screening mechanism for a novel series of COX-2 selective inhibitors. Each compound was represented by calculated structural descriptors that encode constitutional, topological, geometrical, electrostatic, and quantum-chemical features. The heuristic method was then used to search the descriptor space and select the descriptors responsible for activity. Quantitative modelling results in a nonlinear, seven-descriptor model based on SVMs with root mean-square errors of 0.107 and 0.136 for training and prediction sets, respectively. The best classification results are found using SVMs: the accuracy for training and test sets is 91.2% and 88.2%, respectively. This paper proposes a new and effective method for drug design and screening.

Algorithms↗

PubMed1975

Evaluation and selection of optimal solvents and solvent combinations in thin-layer chromatography. Application of the method to basic drugs.

A series of simple mathematical techniques for the evaluation of solvents and solvent combinations in thin-layer chromatography have been investigated. A strategy for the rapid selection of the optimum combination is proposed. It uses classification procedures based on calculation of the similarity between systems. The classification is carried out using a simple graph-theoretical procedure (Kruskal's algorithm) or numerical taxonomy. The selection of optimal sets from the clusters which appear in the classification is based on the information content as derived from Shannon's equation. The method has been applied to an RF data set for basic drugs. It is concluded that these methods indeed allow the selection of optimal systems or combination of systems.

Chromatography, Thin Layer↗