14,020 research outputs found
Relating Developers’ Concepts and Artefact Vocabulary in a Financial Software Module
Developers working on unfamiliar systems are challenged to accurately identify where and how high-level concepts are implemented in the source code. Without additional help, concept location can become a tedious, time-consuming and error-prone task. In this paper we study an industrial financial application for which we had access to the user guide, the source code, and some change requests. We compared the relative importance of the domain concepts, as understood by developers, in the user manual and in the source code. We also searched the code for the concepts occurring in change requests, to see if they could point developers to code to be modified. We varied the searches (using exact and stem matching, discarding stop-words, etc.) and present the precision and recall. We discuss the implication of our results for maintenance
Structural Analysis: Shape Information via Points-To Computation
This paper introduces a new hybrid memory analysis, Structural Analysis,
which combines an expressive shape analysis style abstract domain with
efficient and simple points-to style transfer functions. Using data from
empirical studies on the runtime heap structures and the programmatic idioms
used in modern object-oriented languages we construct a heap analysis with the
following characteristics: (1) it can express a rich set of structural, shape,
and sharing properties which are not provided by a classic points-to analysis
and that are useful for optimization and error detection applications (2) it
uses efficient, weakly-updating, set-based transfer functions which enable the
analysis to be more robust and scalable than a shape analysis and (3) it can be
used as the basis for a scalable interprocedural analysis that produces precise
results in practice.
The analysis has been implemented for .Net bytecode and using this
implementation we evaluate both the runtime cost and the precision of the
results on a number of well known benchmarks and real world programs. Our
experimental evaluations show that the domain defined in this paper is capable
of precisely expressing the majority of the connectivity, shape, and sharing
properties that occur in practice and, despite the use of weak updates, the
static analysis is able to precisely approximate the ideal results. The
analysis is capable of analyzing large real-world programs (over 30K bytecodes)
in less than 65 seconds and using less than 130MB of memory. In summary this
work presents a new type of memory analysis that advances the state of the art
with respect to expressive power, precision, and scalability and represents a
new area of study on the relationships between and combination of concepts from
shape and points-to analyses
Statistical Matching of Administrative and Survey Data : An Application to Wealth Inequality Analysis
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Using population representative survey data from the German Socio-Economic Panel (SOEP) and administrative pension records from the Statutory Pension Insurance, the authors compare four statistical matching techniques to complement survey information on net worth with social security wealth (SSW) information from the administrative records. The unique properties of the linked data allow for a straight control of the quality of matches under each technique. Based on various evaluation criteria, Mahalanobis distance matching performs best. Exploiting the advantages of the newly assembled data, the authors include SSW in a wealth inequality analysis. Despite its quantitative relevance, SSW is thus far omitted from such analyses because adequate micro data are lacking. The inclusion of SSW doubles the level of net worth and decreases inequality by almost 25 percent. Moreover, the results reveal striking differences along occupational lines.Hans Böckler-Foundation, 2006-835-4, Erstellung und Analyse einer konsistenten Geld- und Realvermögensverteilungsrechnung für Personen und Haushalte 2002 und 2007 unter Berücksichtigung der personellen Einkommensverteilun
Hierarchical growing cell structures: TreeGCS
We propose a hierarchical clustering algorithm (TreeGCS) based upon the Growing Cell Structure (GCS) neural network of Fritzke. Our algorithm refines and builds upon the GCS base, overcoming an inconsistency in the original GCS algorithm, where the network topology is susceptible to the ordering of the input vectors. Our algorithm is unsupervised, flexible, and dynamic and we have imposed no additional parameters on the underlying GCS algorithm. Our ultimate aim is a hierarchical clustering neural network that is both consistent and stable and identifies the innate hierarchical structure present in vector-based data. We demonstrate improved stability of the GCS foundation and evaluate our algorithm against the hierarchy generated by an ascendant hierarchical clustering dendogram. Our approach emulates the hierarchical clustering of the dendogram. It demonstrates the importance of the parameter settings for GCS and how they affect the stability of the clustering
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