Knowledge bases in medicine: a review

Efforts to represent knowledge effectively have been central to progress in various aspects of medical informatics. These efforts range from relatively simple "electronic textbooks" to fairly sophisticated knowledge-based systems, which function as well as, or even better than, human experts faced with similar problems. Knowledge bases have been developed in many fields, but the relatively limited domains and structured language of medicine, as well as the importance of information in the provision of good medical care, have made research in medical knowledge representation an area of intense activity. This paper reviews representative knowledge bases and knowledge-based systems in medicine: electronic textbooks such as PDQ and the Hepatitis Knowledge Base (HKB), rule-based systems such as MYCIN, causal models (e.g., CASNET), and hypothesis- or frame-based systems, exemplified by PIP and INTERNIST-1. The paper describes the relationships among divergent approaches and provides a sense of current and future trends. It examines problems in knowledge-based systems, particularly in knowledge representation and acquisition, and the responses to these challenges. The latter include the use of domain-independent software shells for constructing knowledge bases, the adaptation and use of previously existing knowledge bases, and multiple uses of the same knowledge base for different purposes.     

How to be Real and Conventional: A Discussion of the Quality Criteria of Official Statistics

Are the categories used to study the social world and acting on it “real” or “conventional”? An empirical answer to that question is given by an analysis of the debates about the “quality” of statistics produced by the European National Institues of statistics in the 1990s. Six criteria of quality were then specified: relevance, accuracy, timeliness, accessibility, comparability and coherence. How do statisticians and users of statistics deal with the tension produced by their objects being both “real” (they exist before their measurement) and “conventionally constructed” (they are in a way, created by these conventions)? In particular, the technical and sociological distinction between the criteria of relevance and accuracy implies a realistic interpretation, desired by users, but that is nonetheless problematic.     

On the Complexity of the Reduction of Multidimensional Data Models

In this paper, decomposition methods for multidimensional data hypercubes of OLAP systems are investigated. Criteria for reducing the computational complexity of the decomposition methods are presented and comparisons are made with the traditional solutions of multidimensional data analysis problems. Examples illustrating the application of these criteria to investigating the dynamics of computational complexity changes for specific types of reduction problems are considered.     

求解有约束最优化问题的不连续罚函数积分总极值法

1IntroductionLetXbe a topological space ,Sa nonempty subsetofXandf:X→Ra real-valued function.Consider thefollowing constrained opti mization problem:c*=infx∈Sf(x) , (1)and the set of global mini mizers :H*={x∈S|f(x) =c*} (2)under the assumptions (see Refs .[1] and [2]) :(A) :fis lower semi-continuous ,Sis closed andthere is a real numberbsuch that the setHb={x∈S|f(x)≤b} is a nonempty compact set ;(R) :fis upper robust onS,i.e.,{x∈S|f(x) 相似文献   

Developing a scale for using Facebook as a learning tool

This study investigates the development of an instrument to explore the views of student teachers in Turkey towards using Facebook as a tool for teaching and learning. A five-point Likert-type scale was developed for a sample of 687 student teachers from various fields in Adiyaman, Mustafa Kemal, and Inonu Universities. The sample included 445 participants in the first application and 242 participants in the second. A literature review, students’ comments, and relevant Facebook research results were considered in order to establish the items for the scale. A comparative analysis of previous studies and instruments yielded an original 33-item pool, and experts’ judgments were consulted to confirm the content validity of the scale. Exploratory and confirmatory factor analyses were conducted to determine the factor structure of the scale, revealing 17 items that could be grouped under three general factors. A Cronbach’s coefficient (α) was employed to determine the internal consistency coefficients for the whole scale and its subscales. Results indicate that this learning scale (FLTS) is a valid and reliable instrument to investigate the use of Facebook as a learning tool.     

Changing Preservice Science Teachers’ Views of Nature of Science: Why Some Conceptions May be More Easily Altered than Others

The purpose of this study was to assess preservice teachers’ views of Nature of Science (NOS), identify aspects that were challenging for conceptual change, and explore reasons why. This study particularly focused on why and how some concepts of NOS may be more easily altered than others. Fourteen preservice science teachers enrolled in a NOS and Science Inquiry course participated in this study. Data were collected by using a pre/post format with the Views of Nature of Science questionnaire (VNOS-270), the Views of Scientific Inquiry questionnaire (VOSI-270), follow-up interviews, and classroom artifacts. The results indicated that most students initially held naïve views about certain aspects of NOS like tentativeness and subjectivity. By the end of the semester, almost all students dramatically improved their understanding about almost all aspects of NOS. However, several students still struggled with certain aspects like the differences between scientific theory and law, tentativeness, and socio-cultural embeddedness. Results suggested that instructional, motivational, and socio-cultural factors may influence if and how students changed their views about targeted NOS aspects. Students thought that classroom activities, discussions, and readings were most helpful to improve their views about NOS. The findings from the research have the potential to translate as practical advice for teachers, science educators, and future researchers.     

Social Loafing in a Co-operative Classroom Task

Social loafing refers to the tendency for individuals to reduce their own personal input when performing as part of group. This phenomenon may be problematic if it exists in educational contexts, given a current emphasis on group collaborative classroom activities. The present study investigated whether social loafing existed in a collaborative educational task, employing groups of three and eight participants. The results indicated that individuals working within the smaller groups were more productive than those working in larger groups, consistent with the social loafing hypothesis. Future research should determine whether the detrimental effects on students' collaborative performance attributable to social loafing are justifiable in terms of gains accrued in other (e.g. interpersonal) domains.     

Pre-kindergarten teachers’ use of transition practices and children's adjustment to kindergarten

This study describes pre-kindergarten teachers’ use of kindergarten transition practices and examined the extent to which these practices were associated with kindergarten teachers’ judgments of children's social, self-regulatory, and academic skills upon their entry into kindergarten. Participants were 722 children from 214 pre-kindergarten classrooms participating in the National Center for Early Development and Learning's (NCEDL) Multi-State Pre-kindergarten Study. Of nine transition practices intended to promote children's adaptation to kindergarten, pre-kindergarten teachers reported implementing, on average, six transition practices, with notable variation across pre-kindergarten classrooms. Children were judged by their kindergarten teachers to have more positive social competencies and fewer problem behaviors when they attended pre-kindergarten classrooms in which more transition activities were implemented and, specifically, in which teachers discussed curricula or specific children with kindergarten teachers. In addition, positive associations between kindergarten teachers’ perceptions of children's social competence and pre-kindergarten transition activities (total number of activities and activities that children experience directly) were stronger for children who experienced social and economic risks. Implications of these findings related to alignment across the pre-kindergarten to kindergarten settings to improve children's school readiness are discussed.     

Developing a Human Nutrition Learning Progression

This paper describes the application of the methodology developed in research on learning progressions to a health-related topic. More specifically, we present a human nutrition learning progression as a hypothesis that now requires empirical validation. The study involved three phases. In the first phase, we analysed the existing literature in the domain of human nutrition. Based on this analysis, phase 2 then involved drawing up a learning progression for this domain and identifying the learning targets and progress variables, as well as the upper and lower anchors. The analysis led us to identify five progress variables, associated with the development of the concepts of food, nutrient, energy and diet, as well as with the ability to classify foods according to their nutrients. Finally, in phase 3, we identified and described the pathways that students may follow in relation to each progress variable. Given its focus on a topic closely linked to personal health, the learning progression may be useful not only as a component of teaching modules that aim to improve scientific literacy but also as a platform for future health education campaigns that seek to promote healthy eating habits among different sectors of the population.