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排序方式: 共有10000条查询结果,搜索用时 15 毫秒
911.
Liu D Cao Y Kim KH Stanek S Doungratanaex-Chai B Lin K Tavanapong W Wong J Oh J de Groen PC 《Computer methods and programs in biomedicine》2007,88(2):152-163
Colonoscopy is an endoscopic technique that allows physicians to inspect the inside of the human colon. During a colonoscopic procedure, a tiny video camera at the tip of the endoscope generates a video signal of the internal mucosa of the colon. In current practice, the entire colonoscopic procedure is not routinely captured. Software tools providing easy access to important contents of videos that are digitally captured during colonoscopy are not available. Hence, it is very time consuming to review an entire video, locate important contents, annotate them, and extract the annotated contents for research, teaching, and training purposes. Arthemis, a software application, was developed to facilitate this process. For convenient data sharing, Arthemis allows annotation according to the European Gastrointestinal Society for Endoscopy (ESGE) Minimal Standard Terminology (MST), an internationally accepted standard for digestive endoscopy. Arthemis is part of our integrated capturing and content analysis system for colonoscopy called Endoscopic Multimedia Information System (EMIS). This paper presents Arthemis as a component of EMIS, the design and implementation of Arthemis, and key lessons learned from the development process. 相似文献
912.
We consider the edit distance with moves on the class of words and the class of ordered trees. We first exhibit a simple tester
for the class of regular languages on words and generalize it to the class of ranked and unranked regular trees. We also show
that this distance problem is
-complete on ordered trees.
A preliminary version of this paper appeared in Proceedings of 31st International Colloquium on Automata, Languages and Programming, volume 3142 of Lecture Notes in Computer Science, pages 932–944, Springer, 2005. Work supported by ACI Sécurité Informatique: VERA of the French Ministry of research. 相似文献
913.
L. M. Laita E. Roanes-LozanoV. MaojoE. Roanes-MacíasL. de LedesmaL. Laita 《Computers & Mathematics with Applications》2001,42(12):1505-1522
This article presents the development of an expert system for managing medical appropriateness criteria together with an outline of its theoretical foundations. Techniques borrowed from computer algebra (Gröbner bases) are applied to this field of medicine.
The steps of the expert system construction process are as follows. First, the knowledge provided in table format by experts in coronary diseases is translated into a set of production rules of a rule-based expert system (RBES). Kleene's three-valued logic augmented with modal operators is chosen in order to manage uncertainty. 相似文献
914.
Luiz Marcio Cysneiros Julio Cesar Sampaio do Prado Leite Jaime de Melo Sabat Neto 《Requirements Engineering》2001,6(2):97-115
The development of complex information systems calls for conceptual models that describe aspects beyond entities and activities.
In particular, recent research has pointed out that conceptual models need to model goals, in order to capture the intentions
which underlie complex situations within an organisational context. This paper focuses on one class of goals, namely non-functional
requirements (NFR), which need to be captured and analysed from the very early phases of the software development process.
The paper presents a framework for integrating NFRs into the ER and OO models. This framework has been validated by two case
studies, one of which is very large. The results of the case studies suggest that goal modelling during early phases can lead
to a more productive and complete modelling activity. 相似文献
915.
Clarisse Sieckenius de Souza Simone Diniz Junqueira Barbosa Raquel Oliveira Prates 《Knowledge》2001,14(8):461-465
Designing software involves good perception, good reasoning, and a talent to express oneself effectively through programming and interactive languages. Semiotic theories can help HCI designers increase their power to perceive, reason and communicate. By presenting some of the results we have reached with semiotic engineering over the last few years, we suggest that the main contributions of semiotic theory in supporting HCI design are: to provide designers with new perceptions on the process and product of HCI design; to bind together all the stages of software development and use, giving them a unique homogeneous treatment; and to pose innovative questions that extend the frontiers of HCI investigations. 相似文献
916.
Making Workflow Change Acceptable 总被引:1,自引:0,他引:1
Virtual professional communities are supported by network information systems composed from standard Internet tools. To satisfy
the interests of all community members, a user-driven approach to requirements engineering is proposed that produces not only
meaningful but also acceptable specifications. This approach is especially suited for workflow systems that support partially structured, evolving work
processes. To ensure the acceptability, social norms must guide the specification process. The RENISYS specification method
is introduced, which facilitates this process using composition norms as formal representations of social norms. Conceptual
graph theory is used to represent four categories of knowledge definitions: type definitions, state definitions, action norms
and composition norms. It is shown how the composition norms guide the legitimate user-driven specification process by analysing
a case on the development of an electronic law journal. 相似文献
917.
Whereas there is a number of methods and algorithms to learn regular languages, moving up the Chomsky hierarchy is proving
to be a challenging task. Indeed, several theoretical barriers make the class of context-free languages hard to learn. To
tackle these barriers, we choose to change the way we represent these languages. Among the formalisms that allow the definition
of classes of languages, the one of string-rewriting systems (SRS) has outstanding properties. We introduce a new type of
SRS’s, called Delimited SRS (DSRS), that are expressive enough to define, in a uniform way, a noteworthy and non trivial class
of languages that contains all the regular languages,
,
, the parenthesis languages of Dyck, the language of Lukasiewicz, and many others. Moreover, DSRS’s constitute an efficient
(often linear) parsing device for strings, and are thus promising candidates in forthcoming applications of grammatical inference.
In this paper, we pioneer the problem of their learnability. We propose a novel and sound algorithm (called LARS) which identifies a large subclass of them in polynomial time (but not data). We illustrate the execution of our algorithm
through several examples, discuss the position of the class in the Chomsky hierarchy and finally raise some open questions
and research directions.
This work was supported in part by the IST Program of the European Community, under the PASCAL Network of Excellence, IST-2002-506778. This publication only reflects the authors’ views.
Editor: Georgios Paliouras and Yasubumi Sakakibara 相似文献
918.
Observational studies of sitting have shown that, during spontaneous sitting, people adopt a variety of postures. Various researchers have formulated theories to explain why people adopt their sitting postures. Branton (1969) hypothesized that there is continual need for postural stability while sitting. Dempster (1955) stated that additional stability could be obtained through temporarily closing chains of body segments, or, in other words, through decreasing the number of degrees of freedom of the body. The present study elaborates on Dempster's theory. The aim of this study was to determine the influence of the degrees of freedom of the body on postural stability in sitting postures. For 21 different sitting postures, the total number of degrees of freedom was determined. Postural sway, a measure for postural stability, was determined using a 3D motion and position measurement system with ten healthy subjects. This study shows that the mean path length at the level of the second thoracic vertebra (PL0.05), a measure derived from postural sway, increases significantly (p < 0.0001) with an increase of the number of degrees of freedom of the body (DoFB). Closer examination of the data showed that a model taking into account only the degrees of freedom of the lumbar and thoracic spine and pelvis seems to be a better predictor of postural sway than the total number of degrees of freedom of the body. 相似文献
919.
Celina M.H. de Figueiredo Guilherme D. da Fonseca Vinicius G.P. de Sa Jeremy Spinrad 《Algorithmica》2006,46(2):149-180
A homogeneous set is a non-trivial module of a graph, i.e. a non-empty,
non-unitary, proper subset of a graph's vertices such that all its elements
present exactly the same outer neighborhood. Given two graphs
the Homogeneous Set Sandwich Problem (HSSP) asks whether there
exists a sandwich graph
which
has a homogeneous set. In 2001 Tang et al. published
an all-fast
algorithm which was recently proven wrong, so that the HSSP's known upper bound would have been reset
thereafter at the former
determined by Cerioli et al. in 1998. We present, notwithstanding, new deterministic
algorithms which have it established at
We give as
well two even faster
randomized algorithms, whose simplicity might
lend them didactic usefulness. We believe that, besides providing efficient
easy-to-implement procedures to solve it, the study of these new approaches
allows a fairly thorough understanding of the problem. 相似文献
920.
Making decisions can be hard, but it can also be facilitated. Simple heuristics are fast and frugal but nevertheless fairly accurate decision rules that people can use to compensate for their limitations in computational capacity, time, and knowledge when they make decisions [Gigerenzer, G., Todd, P. M., & the ABC Research Group (1999). Simple Heuristics That Make Us Smart. New York: Oxford University Press.]. These heuristics are effective to the extent that they can exploit the structure of information in the environment in which they operate. Specifically, they require knowledge about the predictive value of probabilistic cues. However, it is often difficult to keep track of all the available cues in the environment and how they relate to any relevant criterion. This problem becomes even more critical if compound cues are considered. We submit that knowledge about the causal structure of the environment helps decision makers focus on a manageable subset of cues, thus effectively reducing the potential computational complexity inherent in even relatively simple decision-making tasks. We review experimental evidence that tested this hypothesis and report the results of a simulation study. We conclude that causal knowledge can act as a meta-cue for identifying highly valid cues, either individual or compound, and helps in the estimation of their validities. 相似文献