A case study comparing defect profiles of a reused framework and of applications reusing it

The benefits of software reuse have been studied for many years. Several previous studies have observed that reused software has a lower defect density than newly built software. However, few studies have investigated empirically the reasons for this phenomenon. To date, we have only the common sense observation that as software is reused over time, the fixed defects will accumulate and will result in high-quality software. This paper reports on an industrial case study in a large Norwegian Oil and Gas company, involving a reused Java class framework and two applications that use that framework. We analyzed all trouble reports from the use of the framework and the applications according to the Orthogonal Defect Classification (ODC), followed by a qualitative Root Cause Analysis (RCA). The results reveal that the framework has a much lower defect density in total than one application and a slightly higher defect density than the other. In addition, the defect densities of the most severe defects of the reused framework are similar to those of the applications that are reusing it. The results of the ODC and RCA analyses reveal that systematic reuse (i.e. clearly defined and stable requirements, better design, hesitance to change, and solid testing) lead to lower defect densities of the functional-type defects in the reused framework than in applications that are reusing it. However, the different “nature” of the framework and the applications (e.g. interaction with other software, number and complexity of business logic, and functionality of the software) may confound the causal relationship between systematic reuse and the lower defect density of the reused software. Using the results of the study as a basis, we present an improved overall cause–effect model between systematic reuse and lower defect density that will facilitate further studies and implementations of software reuse.

DanNet: the challenge of compiling a wordnet for Danish by reusing a monolingual dictionary

This paper is a contribution to the discussion on compiling computational lexical resources from conventional dictionaries. It describes the theoretical as well as practical problems that are encountered when reusing a conventional dictionary for compiling a lexical-semantic resource in terms of a wordnet. More specifically, it describes the methodological issues of compiling a wordnet for Danish, DanNet, from a monolingual basis, and not—as is often seen—by applying the translational expansion method with Princeton WordNet as the English source. Thus, we apply as our basis a large, corpus-based printed dictionary of modern Danish. Using this approach, we discuss the issues of readjusting inconsistent and/or underspecified hyponymy hierarchies taken from the conventional dictionary, sense distinctions as opposed to the synonym sets of wordnets, generating semantic wordnet relations on the basis of sense definitions, and finally, supplementing missing or implicit information.     

Optimization of friction stir welding using space mapping and manifold mapping—an initial study of thermal aspects

The aim of this paper is to optimize a thermal model of a friction stir welding process by finding optimal welding parameters. The optimization is performed using space mapping and manifold mapping techniques in which a coarse model is used along with the fine model to be optimized. Different coarse models are applied and the results and computation time are compared to gradient based optimization using the full model. It is found that the use of space and manifold mapping reduces the computational cost significantly due to the fact that fewer function evaluations and no fine model gradient information is required.     

Evaluation of a type 1 diabetes serum cohort by SELDI-TOF MS protein profiling

Proteomics analysis of serum from patients with type 1 diabetes (T1D) may lead to novel biomarkers for prediction of disease and for patient monitoring. However, the serum proteome is highly sensitive to sample processing and before proteomics biomarker research serum cohorts should preferably be examined for potential bias between sample groups. SELDI‐TOF MS protein profiling was used for preliminary evaluation of a biological‐bank with 766 serum samples from 270 patients with T1D, collected at 18 different paediatric centers representing 15 countries in Europe and Japan over 2 years (2000–2002). Samples collected 1 (n = 270), 6 (n = 248), and 12 (n = 248) months after T1D diagnosis were grouped across centers and compared. The serum protein profiles varied with collection site and day of analysis; however, markers of sample processing were not systematically different between samples collected at different times after diagnosis. Three members of the apolipoprotein family increased with time in patient serum collected 1, 6, and 12 months after diagnosis (ANOVA, p<0.001). These results support the use of this serum cohort for further proteomic studies and illustrate the potential of high‐throughput MALDI/SELDI‐TOF MS protein profiling for evaluation of serum cohorts before proteomics biomarker research.     

Non-Hierarchical Architected Materials with Extreme Stiffness and Strength

Stretch-dominated truss and plate microstructures are contenders in the quest for realizing architected materials with extreme stiffness and strength. In the low volume fraction limit, closed-cell isotropic plate microstructures meet theoretical upper bounds on stiffness but have low buckling strength, whereas open-cell truss microstructures have high buckling strength at the cost of significantly reduced stiffness. At finite volume fractions, the picture becomes less clear but both are outperformed by hollow truss lattice and hierarchical microstructures in terms of buckling strength. Despite significant advances in manufacturing methods, hollow and multi-scale hierarchical microstructures are still challenging to build. The question is if there exist realizable microstructures providing stiffness and strength matching or even beating hard-to-realize hollow or hierarchical microstructures? Herein, single-scale non-hierarchical (first order) microstructures that beat the buckling strength of hollow truss lattice structures by a factor of 2.4 and first- and second-order plate microstructures by factors of 5 and 1.4, respectively, are systematically designed, built, and tested. Stiffness of the microstructures is within 40% of theoretical bounds and beats both truss and second order plate microstructures. The microstructures are realized with 3D printing. Experiments validate theoretical predictions and additional insight is provided through numerical modeling of a CT-scanned sample.     

Pseudo-T2 mapping for normalization of T2-weighted prostate MRI

Magnetic Resonance Materials in Physics, Biology and Medicine - Signal intensity normalization is necessary to reduce heterogeneity in T2-weighted (T2W) magnetic resonance imaging (MRI) for...     

The Formation of Calcified Nanospherites during Micropetrosis Represents a Unique Mineralization Mechanism in Aged Human Bone

Osteocytes—the central regulators of bone remodeling—are enclosed in a network of microcavities (lacunae) and nanocanals (canaliculi) pervading the mineralized bone. In a hitherto obscure process related to aging and disease, local plugs in the lacuno‐canalicular network disrupt cellular communication and impede bone homeostasis. By utilizing a suite of high‐resolution imaging and physics‐based techniques, it is shown here that the local plugs develop by accumulation and fusion of calcified nanospherites in lacunae and canaliculi (micropetrosis). Two distinctive nanospherites phenotypes are found to originate from different osteocytic elements. A substantial deviation in the spherites' composition in comparison to mineralized bone further suggests a mineralization process unlike regular bone mineralization. Clearly, mineralization of osteocyte lacunae qualifies as a strong marker for degrading bone material quality in skeletal aging. The understanding of micropetrosis may guide future therapeutics toward preserving osteocyte viability to maintain mechanical competence and fracture resistance of bone in elderly individuals.     

The Effects of Debonding on the Low-Velocity Impact Response of Steel-CFRP Fibre Metal Laminates

The effect of metal-composite debonding on low-velocity impact response, i.e. on contact force–central deflection response, deformation profiles and strains on the free surfaces was studied. We focused on type 2/1 fibre metal laminate specimens made of stainless steel and carbon fibre epoxy layers, and tested them with drop-weight impact and quasi-static indentation loadings. Local strains were measured with strain gauges and full-field strains with a 3-D digital image correlation method. In addition, finite element simulations were performed and the effects of debonding were studied by exploiting cohesive elements. Our results showed that debonding, either the initial debonding or that formed during the loading, lowers the slope of the contact force–central deflection curve during the force increase. The debonding formation during the rebound phase was shown to amplify the rebound of the impact side, i.e. to lower the ultimate post-impact deflection. The free surface strains were studied on the laminate’s lower surface at the area outside the debond damage. In terms of in-plane strains, debonding formation during impact and indentation, as well as the initial debonding, lowered the peripheral strain and resulted in a positive change in the radial strain.     

The mitigation hierarchy upside down – a study of nature protection measures in Danish infrastructure projects

This paper presents a Danish study of mitigation directed at nature protection in environmental impact assessment (EIA) of infrastructure projects. The study is based on a document analysis of EIA reports, a workshop held with EIA professionals, and a study of two cases. The paper takes a point of departure in the mitigation hierarchy as a central conceptual framework, identifies which mitigation measures have been suggested in the EIA reports, and compares this to the mitigation hierarchy. Further, the paper explores the dynamics behind which mitigation measures are chosen and later implemented. The findings point to a discrepancy between the prevention principle embedded in the mitigation hierarchy and the actual EIA practice with increased use of nature compensation. Further, the research reveals significant variation in the design of mitigation measures, e.g. in the level of detail used in describing them and the level of clarity as to aims and actions.