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PubMed1981

Development of logical search and visual scanning in children.

Children at 5, 6, 7, and 8 years of age were told a story in which a doll traveled through a physical model of a house. The doll had a toy in one room and, then, three rooms after, discovered it to be missing. Tests were made of logical search (i.e., the tendency, when asked to find the toy, to restrict search to the critical area between the rooms). The presence of visual cues that marked the critical area was manipulated, and the visual scanning of these cues was monitored. Children in the two younger groups exhibited virtually no logical search either when cues were absent or present, 7-year-old children showed logical search only when cues were present, and 8-year-old children showed logical search both when cues were absent and present. In the cues-present conditions logical search was related to visual scanning of the cues.

Child↗
PubMed1991

An investigation of the optimization of search logic for the MEDLINE database.

One of the key variables in the optimization of the retrieval process is the logic imposed on a set of query terms. If the query is small, a combinatorial algorithm can be employed to identify search expressions having an optimal logical form. An experiment is described in which this was done for queries expressed against MEDLINE, for a variety of criterion variables. The method employed is useful not only for assisting in identifying optimal logical forms, as demonstrated, but also as an experimental control device to assist investigations into the effects of varying the set, and number, of search terms. The experiment also suggests several novel properties of effective searching against MEDLINE, for example that searching with four MeSH terms is likely to be more successful than searching with a lesser number of terms, provided search logic is optimal. The latter result is, surprisingly, true for both Precision and Recall, i.e., a tradeoff between the maximally attainable values of these variables fails to hold when the number of search terms varies in this range.

Algorithms↗
PubMed2002

Pain model and fuzzy logic patient-controlled analgesia in shock-wave lithotripsy.

Pain control in conscious patients was investigated using a push-button, demand-driven supply of drugs. A fuzzy logic patient-controlled analgesia (PCA) algorithm was compared with a conventional algorithm, for alfentanil administration in extracorporeal shock-wave lithotripsy. The conventional PCA algorithm used an initial dose of 0.25mg, a fixed infusion rate of 60 mg h(-1) and a fixed bolus size of 0.2 mg with a 1 min lockout. The fuzzy logic PCA algorithm used an initial dose of 0.25 mg, a changeable infusion rate and a bolus size of 0.1 or 0.05 mg. The infusion rate was adjusted according to a look-up table that accepted the button-pressing history over the last three lockout intervals. The look-up table was designed using fuzzy logic. The bolus size was adjusted according to the button-pressing history over the past two lockout intervals. Twelve patients were treated using conventional PCA, and thirteen were treated with PCA + fuzzy logic control (FLC). PCA + FLC patients consumed 45% less drug. Also, PCA + FLC patients had a mean delivery/demand ratio of 82%, compared with 60% in conventional PCA. When the pain intensity scale was analysed, PCA + FLC patients had acceptable pain intensity at 62%, compared with 44% in conventional PCA.

Adult↗
PubMed1994

Fuzzy-logic control of blood pressure through enflurane anesthesia.

OBJECTIVE: The objective of our study was to construct a closed-loop blood pressure control system using fuzzy logic during enflurane anesthesia. METHODS: Direct systolic blood pressure (SBP), the input variable, was assessed by a special fuzzy-logic membership function--that is, a triangulate continuum of grades between 0 and 1. We also set up the output membership function for the inhaled enflurane concentration. Four fuzzy-rule maps, or matrices, which determined the relationship between the changes of input variables and output values, were constructed based on published anesthetic values. The first map was based on the end-tidal anesthetic concentration known to block an adrenergic response. The fourth map was derived from the anesthetic effective dose (AD95). Fuzzy inference, arrived at by using fuzzy logic, followed the minimum-maximum center of gravity method. Anesthetic control started with the first map and was maintained with the succeeding maps. RESULTS: During anesthesia, the SBP remained within +/- 20% of the preanesthetic SBPs in 82% of the fuzzy control cases and within 83% during manual control. The difference was not significant. CONCLUSION: The anesthetist's management of the administration of the inhaled anesthetic enflurane was imitated by fuzzy-logic control of the blood pressure.

Adult↗
PubMed2003

Fuzzy logic-based tumor marker profiles improved sensitivity of the detection of progression in small-cell lung cancer patients.

Tumor markers were used for disease monitoring in small-cell lung cancer patients. The aim of this study was to improve diagnostic efficiency in the detection of tumor progression in small-cell lung cancer patients by using fuzzy logic modeling in combination with a tumor marker panel (NSE, ProGRP, Tumor M2-PK, CYFRA 21-1, and CEA). Thirty-three consecutive small-cell lung cancer patients were included in a prospective study. The changes in blood levels of tumor markers and their analysis by fuzzy logic modeling were compared with the clinical evaluation of response versus non-response to therapy. Clinical monitoring was performed according to the standard criteria of the WHO. Tumor M2-PK was measured in plasma with an ELISA, all other markers were measured in sera. At 90% specificity, clinically detected tumor progression was found by the best single marker, NSE, in 32% of all cases. A fuzzy logic rule-based system employing a tumor marker panel increased the sensitivity significantly (P>0.0001) in small-cell carcinomas to 67% with the threemarker combination NSE/ProGRP/Tumor M2-PK and to 56% with the best two-marker combination ProGRP/Tumor M2-PK, respectively. An improvement of sensitivity was also observed using the two-marker combination of ProGRP/NSE (sensitivity 49%) or NSE/Tumor M2-PK (sensitivity 52%). The fuzzy classifier was able to detect a higher rate of progression in small-cell lung cancer patients compared with the multiple logistic regression analysis using the marker combination NSE/ProGRP/Tumor M2-PK (sensitivity 44%; AUC=0.76). With the fuzzy logic method and different tumor marker panels (NSE, ProGRP and Tumor M2-PK), a new diagnostic tool for the detection of progression in patients with small-cell lung cancer is available.

Aged↗
PubMed2006

A fuzzy logic approach to assess groundwater pollution levels below agricultural fields.

A fuzzy logic approach has been developed to assess the groundwater pollution levels below agricultural fields. The data collected for Kumluca Plain of Turkey have been utilized to develop the approach. The plain is known with its intensive agricultural activities, which imply excessive application of fertilizers. The characteristics of the soils and underlying groundwater for this plain were monitored during the years 1999 and 2000. Additionally, an extensive field survey related to the types and yields of crops, fertilizer application and irrigation water was carried out. Both the soil and groundwater have exhibited high levels of nitrogen, phosphorus and salinity with considerable spatial and temporal variations. The pollution level of groundwater at several established stations within the plain were assessed using Fuzzy Logic. Water Pollution Index (WPI) values are calculated by Fuzzy Logic utilizing the most significant groundwater pollutants in the area namely nitrite, nitrate and orthophosphate together with the groundwater vulnerability to pollution. The results of the calculated WPI and the monitoring study have yielded good agreement. WPI indicated high to moderate water pollution levels at Kumluca plain depending on factors such as agricultural age, depth to groundwater, soil characteristics and vulnerability of groundwater to pollution. Fuzzy Logic approach has shown to be a practical, simple and useful tool to assess groundwater pollution levels.

Agriculture↗
PubMed2025

Boolean matrix logic programming for active learning of gene functions in genome-scale metabolic network models.

Reasoning about hypotheses and updating knowledge through empirical observations are central to scientific discovery. In this work, we applied logic-based machine learning methods to drive biological discovery by guiding experimentation. Genome-scale metabolic network models (GEMs) - comprehensive representations of metabolic genes and reactions - are widely used to evaluate genetic engineering of biological systems. However, GEMs often fail to accurately predict the behaviour of genetically engineered cells, primarily due to incomplete annotations of gene interactions. The task of learning the intricate genetic interactions within GEMs presents computational and empirical challenges. To efficiently predict using GEM, we describe a novel approach called Boolean Matrix Logic Programming (BMLP) by leveraging Boolean matrices to evaluate large logic programs. We developed a new system, [Formula: see text], which guides cost-effective experimentation and uses interpretable logic programs to encode a state-of-the-art GEM of a model bacterial organism. Notably, [Formula: see text] successfully learned the interaction between a gene pair with fewer training examples than random experimentation, overcoming the increase in experimental design space. [Formula: see text] enables rapid optimisation of metabolic models to reliably engineer biological systems for producing useful compounds. It offers a realistic approach to creating a self-driving lab for biological discovery, which would then facilitate microbial engineering for practical applications.

Active learning↗
PubMed1996

Temporal logics and real time expert systems.

This paper introduces temporal logics. Due to the eternal compromise between expressive adequacy and reasoning efficiency that must decided upon in any application, full (first order logic or modal logic based) temporal logics are frequently not suitable. This is especially true in real time expert systems, where a fixed (and usually small) response time must be guaranteed. One such expert system, Fagan's VM, is reviewed, and a delineation is given of how to formally describe and reason with time in medical protocols. It is shown that Petri net theory is a useful tool to check the correctness of formalised protocols.

Expert Systems↗
PubMed1993

Cytoskeletal logic: a model for molecular computation via Boolean operations in microtubules and microtubule-associated proteins.

Adaptive behaviors and dynamic activities within living cells are organized by the cytoskeleton: intracellular networks of interconnected protein polymers which include microtubules (MTs), actin, intermediate filaments, microtubule associated proteins (MAPs) and other protein structures. Cooperative interactions among cytoskeletal protein subunit conformational states have been used to model signal transmission and information processing. In the present work we present a theoretical model for molecular computing in which Boolean logic is implemented in parallel networks of individual MTs interconnected by MAPs. Conformational signals propagate on MTs as in data buses and in the model MAPs are considered as Boolean operators, either as bit-lines (like MTs) where a signal can be transported unchanged between MTs ('BUS-MAP'), or as bit-lines where a Boolean operation is performed in one of the two MAP-MT attachments ('LOGIC-MAP'). Three logic MAPs have been defined ('NOT-MAP, 'AND-MAP', 'XOR-MAP') and used to demonstrate addition, subtraction and other arithmetic operations. Although our choice of Boolean logic is arbitrary, the simulations demonstrate symbolic manipulation in a connectionist system and suggest that MT-MAP networks can perform computation in living cells and are candidates for future molecular computing devices.

Animals↗
PubMed1997

Fuzzy logic pharmacokinetic modeling: application to lithium concentration prediction.

INTRODUCTION: We hypothesized that fuzzy logic could be used for pharmacokinetic modeling. Our objectives were to develop and evaluate a model for predicting serum lithium concentrations with fuzzy logic. METHODS: Steady-state pharmacokinetic data had been previously collected in 10 elderly patients (age range, 67 to 80 years) with depression who were receiving lithium once daily. Each patient had serial serum lithium concentration determinations over one 24-hour period. The resulting 137 data sets initially consisted of five input variables (age, weight, serum creatinine, lithium dose, and time since last dose) and one output variable (serum lithium concentration; range, 0.2 to 1.24 mmol/L). RESULTS: A fuzzy rulebase was created with 87 randomly chosen data sets, and predictions of serum lithium concentration were made on the basis of the remaining 50 data sets. All of the input variables except age and weight were identified as contributing to the fuzzy logic model. The average magnitude of the error in the predictions was 0.13 mmol/L (root mean squared error) with a bias (mean of the prediction errors) of 0.03 mmol/L. CONCLUSIONS: This study indicates that the use of fuzzy logic for pharmacokinetic modeling of lithium for serum concentration predictions is feasible.

Aged↗
PubMed2005

Control loop noise rejection using fuzzy logic.

This paper describes an application of fuzzy logic to noise rejection in a control loop. This new use of fuzzy logic solves the problem of sluggish control loop response when using a set-point range to stop constant valve chattering due to noise in the output signal being sent to a control valve. Multiple related variables and a general understanding of their inter-relationship must be available for this method to be successfully applied. An overview of the specific fuzzy logic method used for this application is presented along with guidelines for the practical application. In addition, this paper includes results from the successful implementation of fuzzy logic to a control loop on a pilot plant distillation column.

Algorithms↗
PubMed2001

Hybrid fuzzy logic committee neural networks for recognition of swallow acceleration signals.

Biological signals are complex and often require intelligent systems for recognition of characteristic signals. In order to improve the reliability of the recognition or automated diagnostic systems, hybrid fuzzy logic committee neural networks were developed and the system was used for recognition of swallow acceleration signals from artifacts. Two sets of fuzzy logic-committee networks (FCN) each consisting of seven member networks were developed, trained and evaluated. The FCN-I was used to recognize dysphagic swallow from artifacts, and the second committee FCN-II was used to recognize normal swallow from artifacts. Several networks were trained and the best seven were recruited into each committee. Acceleration signals from the throat were bandpass filtered, and several parameters were extracted and fed to the fuzzy logic block of either FCN-I or FCN-II. The fuzzified membership values were fed to the committee of neural networks which provided the signal classification. A majority opinion of the member networks was used to arrive at the final decision. Evaluation results revealed that FCN correctly identified 16 out of 16 artifacts and 31 out of 33 dysphagic swallows. In two cases, the decision was ambiguous due to the lack of a majority opinion. FCN-II correctly identified 24 out of 24 normal swallows, and 28 out of 29 artifacts. In one case, the decision was ambiguous due to the lack of a majority opinion. The present hybrid intelligent system consisting of fuzzy logic and committee networks provides a reliable tool for recognition and classification of acceleration signals due to swallowing.

Acceleration↗
PubMedDate not supplied

Challenging the dominant logic of Emergency Departments: guidelines from chaos theory.

Chaos is order without predictability (1 ). Any unfortunate patient who has recently made a trek to an Emergency Department (ED) or even better, has watched the immensely popular TV show, ER, knows that the visit can be a frustrating and a time consuming experience. The waits are so protracted that one can observe all cycles of birth, death, love, and romance in the waiting room. The process is tedious for the patient who must tell one's tale to a triage nurse, a registration clerk, the primary nurse, the nursing care partner, and finally the emergency physician. Then, the patient must face more delays while being pushed, ineffectively, in a horizontal fashion, through vertical functional silos of care, such as laboratory and radiology. The mind-set or dominant logic of this system of ED patient flow assumes that waits are acceptable and unavoidable, and that the function of the ED is to care for only the truly emergent patient. This dominant logic, coupled with the market constraints of population-based versus case-based payment mechanisms, has led to a declining trend in ED visits for the first time in 20 years (2). In order to improve the quality of ED care as well as to increase acceptability for patient and payer, the dominant logic must be challenged. An understanding of chaos theory and perception of the Emergency Department as a complex adaptive system foster methods for challenging the dominant logic.

Emergency Service, Hospital↗
PubMedDate not supplied

A biochemical logic gate using an enzyme and its inhibitor. 1. The inhibitor as switching element.

Molecular-scale logic systems will allow for further miniaturization of information processing assemblies and contribute to a better understanding of brain function. Of much interest are the pertinent biological systems, some of the basic components of which are biomolecular switching elements and enzyme-based logic gates. In this series of accounts, results of investigations are presented on the implementation of an enzyme/inhibitor logic gate operating under the rules of Boolean algebra. In this report (part 1 of the series), consideration is given to the experimental conditions-particularly the irradiation mode-that affect the performance of proflavine as inhibitor of alpha-chymotrypsin. Also, assessments are made on the reversibility of the process involved and the long-term stability of the system. Moreover, using a theoretical conformational analysis of proflavine and its reduction products, detailed features were established regarding their three-dimensional structure, partial charge distribution, and hydrophobicity. Accordingly, an understanding was reached as to the factors affecting the interaction between these compounds and the enzyme. In part 2 of this series, the actual implementation of an AND logic gate will be presented. This gate involves proflavine and a chemically derivatized alpha-chymotrypsin, and its operation relies on the conclusions reached in this report regarding the optimal mode for controlling the inhibitory activity of proflavine.

Animals↗
PubMed2000

Hierarchical rule-based monitoring and fuzzy logic control for neuromuscular block.

OBJECTIVE: The important task for anaesthetists is to provide an adequate degree of neuromuscular block during surgical operations, so that it should not be difficult to antagonize at the end of surgery. Therefore, this study examined the application of a simple technique (i.e., fuzzy logic) to an almost ideal muscle relaxant (i.e., rocuronium) at general anaesthesia in order to control the system more easily, efficiently, intelligently and safely during an operation. METHODS: The characteristics of neuromuscular blockade induced by rocuronium were studied in 10 ASA I or II adult patients anaesthetized with inhalational (i.e., isoflurane) anaesthesia. A Datex Relaxograph was used to monitor neuromuscular block. And, ulnar nerve was stimulated supramaximally with repeated train-of-four via surface electrodes at the wrist. Initially a notebook personal computer was linked to a Datex Relaxograph to monitor electromyogram (EMG) signals which had been pruned by a three-level hierarchical structure of filters in order to design a controller for administering muscle relaxants. Furthermore, a four-level hierarchical fuzzy logic controller using the fuzzy logic and rule of thumb concept has been incorporated into the system. The Student's test was used to compare the variance between the groups. p < 0.05 was considered significant. RESULTS: The system achieved stable control of muscle relaxation with a mean T1% error of -0.19 (SD 0.66) % accommodating a range in mean infusion rate (MIR) of 0.21-0.49 mg x kg(-1) x h(-1). When these results were compared with our previous ones using the same hierarchical structure applied to mivacurium, less variation in the T1% error (p < 0.05) but the same variation in infusion rate were observed. The controller activity of these two drugs showed no significant difference (p > 0.5). However, the consistent medium coefficient variance (CV) of the MIR of both rocuronium (i.e., 36.13 (SD 9.35) %) and mivacurium (i.e., 34.03 (SD 10.76) %) indicated a good controller activity. CONCLUSIONS: The results showed that a hierarchical rule-based monitoring and fuzzy logic control architecture can provide stable control of neuromuscular block despite the considerable individual variation in neuromuscular block required among patients. Also, there was less variation in T1% error compared with that of previous study on mivacurium. Meanwhile, the consistent medium CV of the MIR of both rocuronium and mivacurium indicated a good controller activity which is able to withstand noise, diathermy effect, artifacts and surgical disturbances.

Adolescent↗
PubMed1990

Relation of socioeconomic status to logical and sociomoral judgment of middle-aged men.

Empirical links between socioeconomic status and logical and sociomoral judgment were studied. Logical judgment was measured with adaptations of the pendulum and correlations tasks devised by Inhelder and Piaget (1958); sociomoral judgment was scored with the standard Kohlberg interview. Measures of socioeconomic status (SES) were status of family of origin and subject's educational attainment and occupational prestige. In a sample of 83 middle-aged men, the 3 measures of SES accounted for 25% and 12% of the variance in logical and sociomoral judgment, respectively. Adult occupational prestige accounted for 6% of the variance in logical judgment beyond that explained by family status and education, suggesting that adult cognitive functioning may be related to occupational placement, occupational experience, or both.

Adult↗
PubMed1984

The logical description of a disease class as a Boolean function with special reference to the irritable bowel syndrome.

Although some disease classes can be defined by a single defining characteristic, in terms of traditional logic one that is both necessary and sufficient, other disease classes, such as the so-called "irritable bowel syndrome' (IBS), have only a set of symptoms, signs etc. which are said to characterize it in some undefined way. This characterization might be made definite by using simple Boolean algebra to give a logical description of the disease class. This method can only be used if the individual doctor can be shown to be consistent in his assignment of a set of data to the disease class and also if his assignment agrees independently with that of another doctor. To test such consistency and concordance, 100 case records were collected of supposed IBS and not-IBS; 20 of these were replicated to test consistency, and the total of 120 records was examined by five consultants independently, who assigned them either to an IBS or a not-IBS class. From the 1500 pair-wise comparisons, analysis revealed that the disagreement in assignment between doctors was only slightly greater than the disagreement within doctors, suggesting that the group of doctors acted as if there were an implicit description of IBS with which each of them broadly agreed. This implicit description, if made explicit, could form a basis for diagnosis by logical implication. This method of logical definition has general application in medicine and a set of defined cases could be used to establish entry criteria for multicentre trials of a previously ill-defined class.

Analysis of Variance↗
PubMed1997

[The importance of differential analysis of formal thought disorders in confusion psychosis and cataphasia. Incoherence of thematic choice and incoherence with logical and linguistic errors].

Formal thought disorders are usually regarded as a central symptom of schizophrenic psychoses, but nevertheless as diagnostically non-specific. Karl Leonhard, therefore, differentiated in his classification of endogenous psychoses between a whole lot of diagnostically specific types of formal thought disorders. He described two psychoses, of which formal thought disorder is the main psychopathological feature, i.e. confusion psychosis and cataphasia. By means of an analysis of tape-recorded utterances of patients with such psychoses we demonstrate the phenomenological differentiation of the distinct types of thought disorder in these psychoses. In confusion psychosis the disturbance concerns the thematic organisation and target-oriented direction of the train of thought. Characteristically, an "incoherence of thematic choice" results, reflecting a disturbance on the level of organisation of discourse. The concepts, ideas and themes itself are organised in a logically correct manner and are comprehensible. The thought disorder in cataphasia, however, shows severe logical faults in the connection of concepts and ideas, as a result of which single themes and ideas become a logical and incomprehensible. Moreover, cataphasic thought disorder goes beyond the level of discourse organisation and extends to disturbances of linguistic functions including mistakes on a semantical and syntactic level. These observations correspond well with the widely accepted assumption of a modular organisation of cognitive and linguistic processes. The thought disorder in prognostically unfavourable cataphasia concerns "basal" logical, semantic and syntactic systems, which remain uninfluenced in the prognostically favourable confusion psychosis. In the latter, therefore, the disorder is restricted to the higher functions of organisation of discourse.

Humans↗