A survey of clustering methods

In this paper, I describe a large variety of clustering methods within a single framework. This paper unifies work across different fields, from biology (numerical taxonomy) to machine learning (concept formation). An important objective for this paper is to show that one can benefit by a knowledge of research across different disciplines. After describing the task from a set of different viewpoints or paradigms, I begin by describing the similarity measures or evaluation functions that form the basis of any clustering technique. Next, I describe a number of different algorithms that use these measures, and I close with a brief discussion of ways to evaluate different approaches to clustering

How sticky are local expenditures in Italy? Assessing the relevance of the “flypaper effect” through municipal data

An extensive literature analyses the impact of upper-tier transfers on the spending behaviour of lower level governments. According to the median voter framework, a transfer from the centre should act as a lump sum grant to residents and thus be spent by jurisdictions in the same proportion as residents are willing to spend their own money on public goods and services. But the actual local expenditure response to central government transfers is stronger than predicted by the theory, giving rise to the “flypaper effect”. Using the database on municipal accounts, and various other information sources, this work aims at assessing the size of the effect for Italian municipalities and the symmetry in the local expenditure response to central government transfers. Our dataset enables us also to investigate the role of some political factors. We find a sizeable effect and a remarkable asymmetric response of municipal expenditures to central government transfers as well as a significant role for political variables.flypaper effect, intergovernmental transfers, fiscal federalism

Dynamic Models and Structural Shift: Monetary Transmission Mechanisms in Italy before and after EMS

The focus is on nominal transmission mechanisms in Italy with special reference to monetary effects and how they have changed with the increased economic integration in Europe and the increased independence of Italian Central Bank. The empirical model investigates the dynamic determination of money, income, prices, and interest rates based on the cointegrated VAR model. The choice of price measurements and its consequences for the empirical results are given special attention. The empirical results provide empirical results on the macroeconomic effects of joining the ERM and of capital deregulation.I(2) analysis; regime shift; price homogeneity; money demand; IS-LM; monetary policy

Models of incremental concept formation

Given a set of observations, humans acquire concepts that organize those observations and use them in classifying future experiences. This type of concept formation can occur in the absence of a tutor and it can take place despite irrelevant and incomplete information. A reasonable model of such human concept learning should be both incremental and capable of handling this type of complex experiences that people encounter in the real world. In this paper, we review three previous models of incremental concept formation and then present CLASSIT, a model that extends these earlier systems. All of the models integrate the process of recognition and learning, and all can be viewed as carrying out search through the space of possible concept hierarchies. In an attempt to show that CLASSIT is a robust concept formation system, we also present some empirical studies of its behavior under a variety of conditions

Knowledge Transformations between Frame Systems and RDB Systems

For decades, researchers in knowledge representation (KR) have argued for and against various choices in KR formalisms, such as Rules, Frames, Semantic nets, and Formal logic. In this paper, we present a set of transformations that can be used to move knowledge across two fundamentally different KR formalisms: Frame-based systems and Relational database systems (RDBs). We also describe partial implementations of these transformations for a specific pair of such systems: Protégé and the Postgres RDB system

Integrating Genomic Knowledge Sources through an Anatomy Ontology

Modern genomic research has access to a plethora of knowledge sources. Often, it is imperative that researchers combine and integrate knowledge from multiple perspectives. Although some technology exists for connecting data and knowledge bases, these methods are only just begin-ning to be successfully applied to research in modern cell biology. In this paper, we argue that one way to integrate multiple knowledge sources is through anatomy—both generic cellular anatomy, as well as anatomic knowledge about the tissues and organs that may be studied via microarray gene expression experiments. We present two examples where we have combined a large ontology of human anatomy (the FMA) with other genomic knowledge sources: the gene ontology (GO) and the mouse genomic databases (MGD) of the Jackson Labs. These two initial examples of knowledge integration provide a proof of concept that anatomy can act as a hub through which we can usefully combine a variety of genomic knowledge and data

Semi-automatic Database Design for Neuroscience Experiment Management Systems

Neuroinformatics provides tools for neuroscience researchers to study brain function. In order to handle experiment paradigms that change frequently, we are developing a semiautomatic database design tool that will enable an experiment management system (EMS) to manage data with flexibility while retaining the efficiency of a relational database