首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.

Background  

EpiFlex is a flexible, easy to use computer model for a single computer, intended to be operated by one user who need not be an expert. Its purpose is to study in-silico the epidemic behavior of a wide variety of diseases, both known and theoretical, by simulating their spread at the level of individuals contracting and infecting others. To understand the system fully, this paper must be read together in conjunction with study of the software and its results. EpiFlex is evaluated using results from modeling influenza A epidemics and comparing them with a variety of field data sources and other types of modeling.  相似文献   

2.
Image understanding system for histopathology   总被引:1,自引:0,他引:1  
An image understanding machine vision system for histological diagnoses is based on three interacting expert systems: a diagnostic expert system utilizing terms familiar to pathologists, an interpretive expert system relating human diagnostic concepts to computable histometric features and a scene segmentation expert system which extracts the diagnostic information from the imagery. The control software for the image understanding system resides on a multiprocessor computer. This article details measures to maintain system efficiency and to accommodate the requirements of interprocess communication and processing task scheduling.  相似文献   

3.
The synthesis of an 11 membered ring bis-lactam, a system which is designed as a conformationally restricted mimetic of type I and type II beta-turns is described. Computer assisted molecular modeling was used to compare the predicted low energy conformers of the turn mimetic with idealized type I and type II turn structures. Initial computational analysis indicates that the basic ring structure will provide an excellent foundation for the development of a varieity of beta-turn mimetics.  相似文献   

4.
The mammalian visual system is still the gold standard for recognition accuracy, flexibility, efficiency, and speed. Ongoing advances in our understanding of function and mechanisms in the visual system can now be leveraged to pursue the design of computer vision architectures that will revolutionize the state of the art in computer vision.  相似文献   

5.
6.
昆虫数学形态学研究及其应用展望   总被引:1,自引:0,他引:1  
沈佐锐  于新文 《昆虫学报》1998,41(-1):140-148
数学形态学是用数学方法描述或分析一个物体图象的形状的理论和方法,是图象处理和图象识别技术的发展,但在生物学当中的应用还很有限。本文介绍了一个新的分支学科——昆虫数学形态学,包括三方面的内容:①昆虫数学形态学技术研究,涉及昆虫图象数字化技术和昆虫图象处理与识别技术;②昆虫数学形态学理论研究,主要以昆虫图象的解释和理解研究及昆虫数学形态学与分类学等学科的关系研究为主;③昆虫和昆虫数学形态学应用基础研究,涉及昆虫数学形态学数据库及其分析软件开发,昆虫图象的机器学习和计算机视觉等内容。昆虫数学形态学理论和方法与计算机视觉技术相结合,在害虫虫情监测、昆虫多媒体专家系统的构建等方面具有广阔的应用前景。  相似文献   

7.
Metamorphosis of the amphibian eye   总被引:1,自引:0,他引:1  
For many metamorphosing amphibians, the visual system must remain functional as the animal changes from an aquatic to a terrestrial habitat. Thyroid hormone, the trigger for metamorphosis, brings about changes at all levels of the animal, and profoundly alters the visual system, from cellular changes within the eye to new central connections subserving the binocular vision that develops during metamorphosis in some species. I will survey the alterations in the visual system in the metamorphosis of several Amphibian groups, and consider the role of thyroid hormone in bringing about these transformations through action at the molecular level.  相似文献   

8.
Malone JP  George A  Veis A 《Proteins》2004,54(2):206-215
The in vitro rate and specificity of fibrillogenesis in type I collagen depends on the integrity of the amino (N)-telopeptide domain. In vivo an intact N-telopeptide domain is also required for normal fibril assembly. Although Chou-Fasman predictions and NMR studies suggested that a type I beta-turn could be induced in alpha1(I) N-telopeptide chains, computer modeling did not identify ordered structures. Nevertheless, X-ray analysis and electron tomography studies have shown that the N-telopeptide is in one of the most highly ordered fibril domains. This study was undertaken to determine if the docking of the N-telopeptide to its helix receptor domain could induce the telopeptides to take up a specific conformation. With use of molecular modeling suite of programs, a (Gly-Pro-Pro)(n) triple-helical structure was built on the basis of high-resolution X-ray crystallographic coordinates and then replaced with the actual bovine collagen residues 924-938, the triple-helical alpha1(I)-N-telopeptide-receptor sequences. Energy minimization produced a modified triple-helical conformation. The bovine alpha1(I) N-telopeptide sequence was similarly minimized and docked to this receptor. The docking induced an ordered conformation with a stabilizing hydrogen bond in the N-telopeptide and, importantly, a reciprocal reordering of the triple-helical conformation in the binding domain. This docked structure placed Lys residues in both telopeptide and helix in the correct locations for cross-link formation. The modeling has been extended to the three-chain N-telopeptide domain and finally to the construction of the Hulmes-Miller quasi-hexagonal packing structure. Each N-telopeptide domain can form linkages with two adjacent, aligned helix receptor domains. The telopeptides and the order of staggering of the three chains in the helix play crucial roles in the packing and intrafibrillar cross-linking patterns and the relative azimuthal orientations of adjacent molecules in the fibril. The models confirm the high order in the N-telopeptide 4D overlap zone.  相似文献   

9.
10.
We modeled expert knowledge of arthropod flower-visiting behavioral ecology and represented this in an event-centric domain ontology, which we describe along with the ontology construction process. Two smaller domain ontologies were created to represent expert knowledge of known flower-visiting insect groups and expert knowledge of the flower-visiting behavioral ecology of Rediviva bees. Two application ontologies were designed, which, together with the domain ontologies, constituted the ontology framework of a prototype semantic enrichment and mediation system that we designed and implemented to improve semantic interoperability between flower-visiting data-stores. We describe and evaluate the system implementation in a case-study of three flower-visiting data-stores, and we discuss the system's scalability, extension and potential impact. We demonstrate how the system is able to dynamically extract complex ecological interactions from heterogeneous specimen data-stores. The conceptual stance and modeling approach are potentially of general use in representing knowledge of animal behavior and ecological interactions, and in engineering semantic interoperability between data-stores containing behavioral ecology data.  相似文献   

11.
The evolving technology of computer autofabrication makes it possible to produce physical models for complex biological molecules and assemblies. Augmented reality has recently developed as a computer interface technology that enables the mixing of real-world objects and computer-generated graphics. We report an application that demonstrates the use of autofabricated tangible models and augmented reality for research and communication in molecular biology. We have extended our molecular modeling environment, PMV, to support the fabrication of a wide variety of physical molecular models, and have adapted an augmented reality system to allow virtual 3D representations to be overlaid onto the tangible molecular models. Users can easily change the overlaid information, switching between different representations of the molecule, displays of molecular properties, or dynamic information. The physical models provide a powerful, intuitive interface for manipulating the computer models, streamlining the interface between human intent, the physical model, and the computational activity.  相似文献   

12.
The human visual system is the most complex pattern recognition device known. In ways that are yet to be fully understood, the visual cortex arrives at a simple and unambiguous interpretation of data from the retinal image that is useful for the decisions and actions of everyday life. Recent advances in Bayesian models of computer vision and in the measurement and modeling of natural image statistics are providing the tools to test and constrain theories of human object perception. In turn, these theories are having an impact on the interpretation of cortical function.  相似文献   

13.
The computer molecular modeling program HINT (Hydropathic INTeractions), an empirical hydropathic force field function that includes hydrogen bonding, coulombic and hydrophobic terms, was used to study sequence-selective doxorubicin binding/intercalation in the 64 unique CAxy, CGxy, TAxy, TGxy base pair quartet combinations. The CAAT quartet sequence is shown to have the highest binding score of the 64 combinations. Of the two regularly alternating polynucleotides, d(CGCGCG)2and d(TATATA)2, the HINT calculated binding scores reveal doxorubicin binds preferentially to d(TATATA)2. Although interactions of the chromophore with the DNA base pairs defining the intercalation site [I-1] [I+1] and the neighboring [I+2] base pair are predominant, the results obtained with HINT indicate that the base pair [I+3] contributes significantly to the sequence selectivity of doxorubicin by providing an additional hydrogen bonding opportunity for the N3' ammonium of the daunosamine sugar moiety in approximately 25% of the sequences. This observation, that interactions involving a base pair [I+3] distal to the intercalation site play a significant role in stabilizing/destabilizing the intercalation of doxorubicin into the various DNA sequences, has not been previously reported. In general terms, this work shows that molecular modeling and careful analysis of molecular interactions can have a significant role in designing and evaluating nucleotides and antineoplastic agents.  相似文献   

14.
Computer programs can assist humans in solving complex problems that cannot be solved by traditional computational techniques using mathematic formulas. These programs, or "expert systems," are commonly used in finance, engineering, and computer design. Although not routinely used in medicine at present, medical expert systems have been developed to assist physicians in solving many kinds of medical problems that traditionally require consultation from a physician specialist. No expert systems are available specifically for drug abuse treatment, but at least one is under development. Where access to a physician specialist in substance abuse is not available for consultation, this expert system will extend specialized substance abuse treatment expertise to nonspecialists. Medical expert systems are a developing technologic tool that can assist physicians in practicing better medicine.  相似文献   

15.
The remarkable variation in color vision both among and within primate species is receiving increasing attention from geneticists, psychophysicists, physiologists, and behavioral ecologists. It is known that color vision ability affects foraging behavior. Color vision is also likely to have implications for predation avoidance, social behavior, mate choice, and group dynamics, and should also influence the choice of stimuli for cognitive experiments. Therefore, understanding the color vision of a study species is important and of particular significance to scientists studying species with polymorphic color vision (most platyrrhines and some strepsirrhines). The papers in this issue were inspired by a symposium held during the 20th Congress of the International Primatological Society at Turin, Italy, in August 2004. The aim of the symposium was to bring together research from a range of disciplines, using recent methodological advances in molecular, modeling, and experimental techniques, to help elucidate the evolution, ecological importance, and distribution of color vision genotypes and phenotypes. The symposium achieved its aim, and as with most research in expanding disciplines, there are surprises and many questions still to be answered. Further advances will be made using a combination of different approaches involving analyses at the level of molecu1es, types of cell and neural networks, detailed and long-term field work, modeling, and carefully controlled experimentation.  相似文献   

16.
New advances in Internet technologies and computer modeling provide opportunities for collaborative systems to support research and development in the field of industrial ecology. In particular, new information technologies such as semantic search engines based on ontologies could help researchers to link fragments of knowledge generated at research centers from around the world. Using a storyline of four imaginary researchers who hope to find collaborators in order to develop their research findings, we illustrate two levels of a four-level architecture for an Internet-based knowledge integration and collaboration environment for integrated environmental assessment. The foundation of the proposed architecture is a belief that computational models are an effective medium for conveying expert knowledge of various phenomena. Drawing from this premise, the first level of the architecture stands on a base of computational models that in some way represent the expert knowledge of the model builder. At the second level, we provide markup and interface definition tools to describe the type of knowledge contained in each model, together with the types of information services that can be provided.
The results of research at these two levels of an Internet-based knowledge integration environment for integrated environmental assessment in industrial ecology are presented in this article. Our work on the third level of model searching and matching and the fourth level of parametric model integration and solving will be presented in subsequent articles.  相似文献   

17.
The Nuts and Bolts section of our Journal (mirrored on the ICCNS society web site), is meant to provide a very practical way to share useful information, that goes beyond the scope of cell signaling and basic CCN protein biology. Considering the number of requests we have had for information related to protection of Intellectual Property (IP), I am pleased to initiate what will be a series of articles that will focus on various IP topics. The inaugural topic is the protection of computer programs. Some colleagues may wonder how and why the patentability of computer programs is a topic of interest for scientists working on CCN proteins . . . As a matter of fact, to assist us in analyzing the potential involvement of CCN3 in human genetic diseases, we considered developing a computer program designed to analyze large amounts of data. Sharing the concepts and the computer program raised concerns regarding IP and protection of the software that we would handle. We believe that many colleagues have encountered similar problems. This article provides a short focus on computer program patentability. It is aimed to provide basic legal information, and to help our readers in understanding the process. It is not intended to replace IP counselors or technology transfer departments. Future articles will address other practical aspects of IP protection.  相似文献   

18.
For expert systems intended to aid diagnosis, a structure with five levels is proposed. These levels are the original area, the parameter and a reduced parameter layer, the classification and the final-decision layer. On the basis of this structures, an expert system was developed specifically for neonatal hearing screening with transitory evoked otoacoustic emissions (TEOAE). In a second step, this system was investigated for its suitability to classify emissions, regardless of patient age. For the comparison measurements in 252 mainly adult patients, some with an acquired hearing impairment, were used. To adapt the pass/fail decision to the extended evaluation criteria, the false classifications from a first run with the new data were used for training. Thereafter, the expert system, working with a wider data basis, classified the new data with a sensitivity that was increased by 4.8% to 97.2%, and a 2.0% improvement in specificity to 95.5% when classifying new data, These results, together with those of 97.3% and 94.3% achieved with exclusively neonatal TEOAE classification, clearly show the advantage of the expert system structures chosen, and document evidence of the practical applicability of the method.  相似文献   

19.
B Houwen 《Blood cells》1989,15(3):509-27; discussion 527-32
A new expert system developed on a Macintosh personal computer using a commercially available artificial intelligence shell was compared with four different discriminant functions (DFs) for the differentiation of microcytic anemia into etiologic categories. Several databases were used with a different composition but all contained at least some samples from thalassemic individuals and from patients with iron deficiency anemia. The DFs analyzed were those proposed by England and Fraser, Green and colleagues, Mentzer, and by Shine and Lal. None of the databases performed satisfactorily when used singly, whereas very high false-positive rates were obtained by one of them. The diagnostic efficiency was somewhat improved by combining several DFs. An expert system using an artificial intelligence "shell" with an "interference engine" was developed using cluster analysis and a set of learning examples. The input necessary for the system to achieve a conclusion consists of MCV, RBC, and RDW as well as a statement as to whether the patient has anemia. Based upon the values of these parameters, the expert system will give an "advice" regarding the probabilities for thalassemia, iron deficiency, and/or other probabilities such as previous transfusions, anemia of chronic disease, laboratory error, etc. In a prospective trial, the system functioned with an accuracy of better than 85%.  相似文献   

20.
Ecological niche modeling is used to estimate species distributions based on occurrence records and environmental variables, but it seldom includes explicit biotic or historical factors that are important in determining the distribution of species. Expert knowledge can provide additional valuable information regarding ecological or historical attributes of species, but the influence of integrating this information in the modeling process has been poorly explored. Here, we integrated expert knowledge in different stages of the niche modeling process to improve the representation of the actual geographic distributions of Mexican primates (Ateles geoffroyi, Alouatta pigra, and A. palliata mexicana). We designed an elicitation process to acquire information from experts and such information was integrated by an iterative process that consisted of reviews of input data by experts, production of ecological niche models (ENMs), and evaluation of model outputs to provide feedback. We built ENMs using the maximum entropy algorithm along with a dataset of occurrence records gathered from a public source and records provided by the experts. Models without expert knowledge were also built for comparison, and both models, with and without expert knowledge, were evaluated using four validation metrics that provide a measure of accuracy for presence-absence predictions (specificity, sensitivity, kappa, true skill statistic). Integrating expert knowledge to build ENMs produced better results for potential distributions than models without expert knowledge, but a much greater improvement in the transition from potential to realized geographic distributions by reducing overprediction, resulting in better representations of the actual geographic distributions of species. Furthermore, with the combination of niche models and expert knowledge we were able to identify an area of sympatry between A. palliata mexicana and A. pigra. We argue that the inclusion of expert knowledge at different stages in the construction of niche models in an explicit and systematic fashion is a recommended practice as it produces overall positive results for representing realized species distributions.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号