INTRODUCTION: Systematic approaches to dealing with missing values in record linkage are still lacking. This article compares the ad-hoc treatment of unknown comparison values as 'unequal' with other and more sophisticated approaches. An empirical evaluation was conducted of the methods on real-world data as well as on simulated data based on them. MATERIAL AND METHODS: Cancer registry data and artificial data with increased numbers of missing values in a relevant variable are used for empirical comparisons. As a classification method, classification and regression trees were used. On the resulting binary comparison patterns, the following strategies for dealing with missingness are considered: imputation with unique values, sample-based imputation, reduced-model classification and complete-case induction. These approaches are evaluated according to the number of training data needed for induction and the F-scores achieved. RESULTS: The evaluations reveal that unique value imputation leads to the best results. Imputation with zero is preferred to imputation with 0.5, although the latter shows the highest median F-scores. Imputation with zero needs considerably less training data, it shows only slightly worse results and simplifies the computation by maintaining the binary structure of the data. CONCLUSIONS: The results support the ad-hoc solution for missing values 'replace NA by the value of inequality'. This conclusion is based on a limited amount of data and on a specific deduplication method. Nevertheless, the authors are confident that their results should be confirmed by other empirical analyses and applications.

Software processes, such as RUP and agile methods, focus their requirements engineering part on use cases and thus functional requirements. Complex products, such as radio network control software, need special handling of non-functional requirements as well. We describe how we used the eclipse process framework to augment the open and minimal OpenUP/basic process with improvements found in management of capacity requirements in a case-study at Ericsson. The result is compared with another project improving RUP to handle performance requirements. The major differences between the improvements are that 1) they suggest a special, dedicated performance manager role and we suggest that present roles are augmented, 2) they suggest a bottom-up approach to performance verification while we focus on system performance first, i.e. top-down. Further, we suggest augmenting Um l-2 models with capacity attributes to improve information flow from requirements to implementation.

Capacity in telecommunication systems is highly related to operator revenue. As a vendor of such systems, Ericsson AB is continuously improving its processes for estimating, specifying, tuning, and testing the capacity of delivered systems. In order to systematize process improvements Ericsson AB and Linköping University joined forces to create an anatomy of Capacity Sub Processes (CSPs). The anatomy is the result of an interview series conducted to document good practices amongst organizations active in capacity improvement. In this paper we analyze four different development processes in terms of how far they have reached in their process maturity according to our anatomy and show possible improvement directions. Three of the processes are currently in use at Ericsson, and the fourth is the OpenUP/Basic process which we have used as a reference process in earlier research. We also include an analysis of the observed good practices. The result mainly confirms the order of CSPs in the anatomy, but we need to use our information of the maturity of products and the major life cycle in the organization in order to fully explain the role of the anatomy in planning of improvements.

There is evidence to suggest that the software industry has not yet matured as regards management of nonfunctional requirements (NFRs). Consequently the cost of achieving required quality is unnecessarily high. To try and avoid this, the telecommunication systems provider Ericsson defined a research task to try and improve the management of requirements for capacity, which is one of the most critical NFRs. Linkoping University joined in the effort and conducted an interview series to investigate good practice within different parts of the company. Inspired by the interviews and an ongoing process improvement project a model for improvement was created and activities were synthesized. This paper contributes the results from the interview series, and details the subprocesses of specification that should be improved. Such improvements are about understanding the relationship between numerical entities at all system levels, augmenting UML specifications to make NFRs visible, working with time budgets, and testing the sub system level components on the same level as they are specified