Quadratic-time algorithm for a string constrained LCS problem

The problem of finding a longest common subsequence of two main sequences with some constraint that must be a substring of the result (STR-IC-LCS) was formulated recently. It is a variant of the constrained longest common subsequence problem. As the known algorithms for the STR-IC-LCS problem are cubic-time, the presented quadratic-time algorithm is significantly faster.     

Design and implementation of multiaxial force sensing gripper fingers

This paper focuses on the integration of elementary force sensors into the fingers of parallel grippers. The theory of the approach of integrating three sensor elements into a gripper finger is described and the results of the practical evaluations are given. Strain gauges are used as elementary sensor elements. Two different design approaches are evaluated. The first one uses H-shaped cut-outs to weaken the structure at designated areas. The measurement accuracy of this system is compared with a second approach without cut-outs, which is easier to manufacture. Finite element analysis is used in both approaches to simulate the behaviour and to determine the best locations for strain gauge application. The performances of both design concepts are experimentally evaluated. It can be seen that the results of the finite-element analysis are correct and that a satisfactory decoupling of the basic sensors can be achieved using a physical or mathematical approach. Both prototypes are able to measure the gripping force with sufficient accuracy.     

Designing in between Local Government and the Public – Using Institutional Analysis in Interventions on Civic Infrastructures

Adapting and changing the systems and technologies involved in civic engagement with local government is among the key challenges of collaborative technologies for political participation. In such contexts, both existing sets of technologies and ingrained, often formalised practices, the ‘rules of the game’, constrain any opportunity for intervention. Additionally, ‘civic’ and expert groups with conflicting agendas and divergent demands on public choices assert their influence in these transformation programmes. The article argues that established methods in collaborative systems design have thus far overlooked the role of recurring actions involved in public participation as well as the formal rules and ingrained practices that construct them. Yet, such patterns present a valuable resource for design interventions. Thus, based on an institutional approach, the article outlines a methodology for requirement gathering by mapping the relations of actors, software and their use along identifiable action situations. The method called for a dialogue between socio-technical-spatial contexts of public service and specific actions taking place within it. Drawing on a case of organising civic engagement in urban planning, the article discusses how to find and trace existing practices across social settings, information technologies and material contexts where engagements take place. The approach underscores the existing institutional contexts in inspiring, opening and constraining the opportunities to support ‘civics’.     

Statistical analysis of manual segmentations of structures in medical images

The problem of extracting anatomical structures from medical images is both very important and difficult. In this paper we are motivated by a new paradigm in medical image segmentation, termed Citizen Science, which involves a volunteer effort from multiple, possibly non-expert, human participants. These contributors observe 2D images and generate their estimates of anatomical boundaries in the form of planar closed curves. The challenge, of course, is to combine these different estimates in a coherent fashion and to develop an overall estimate of the underlying structure. Treating these curves as random samples, we use statistical shape theory to generate joint inferences and analyze this data generated by the citizen scientists. The specific goals in this analysis are: (1) to find a robust estimate of the representative curve that provides an overall segmentation, (2) to quantify the level of agreement between segmentations, both globally (full contours) and locally (parts of contours), and (3) to automatically detect outliers and help reduce their influence in the estimation. We demonstrate these ideas using a number of artificial examples and real applications in medical imaging, and summarize their potential use in future scenarios.     

Suitable Impact Parameters for High-Speed Joining and Influence on the Bonding Zone Microstructure

Welding by electromagnetic forming is an interesting alternative for material combinations which are not suitable for conventional welding by melting. Even though the underlying bonding mechanisms and the right choice of process parameters are thoroughly discussed in the current literature, there is still a lack of target-oriented process dimensioning. The present paper describes the model experiment used for studying the dependencies between bonding quality and design parameters for three material combinations (mild steel, aluminum base alloy, pure titanium). The resulting bonding zones were analyzed by means of optical microscopy and electron probe microanalyses. Limits for the process parameters are described and the results demonstrate increasing bonding qualities for increasing collision energies and collision angles.