Regularization in statistics

This paper is a selective review of the regularization methods scattered in statistics literature. We introduce a general conceptual approach to regularization and fit most existing methods into it. We have tried to focus on the importance of regularization when dealing with today's high-dimensional objects: data and models. A wide range of examples are discussed, including nonparametric regression, boosting, covariance matrix estimation, principal component estimation, subsampling.     

Entropic interactions in soft nanomaterials

We review the forces that rule interactions between phospholipid membranes and other soft nanomaterials such as polymers and colloids. Contrary to traditional nanostructures, soft materials display a high susceptibility to the fluctuations of the thermal environment, leading to new forces of an essentially entropic nature.     

Contact-tracing in cultural evolution: a Bayesian mixture model to detect geographic areas of language contact

When speakers of different languages interact, they are likely to influence each other: contact leaves traces in the linguistic record, which in turn can reveal geographical areas of past human interaction and migration. However, other factors may contribute to similarities between languages. Inheritance from a shared ancestral language and universal preference for a linguistic property may both overshadow contact signals. How can we find geographical contact areas in language data, while accounting for the confounding effects of inheritance and universal preference? We present sBayes, an algorithm for Bayesian clustering in the presence of confounding effects. The algorithm learns which similarities are better explained by confounders, and which are due to contact effects. Contact areas are free to take any shape or size, but an explicit geographical prior ensures their spatial coherence. We test sBayes on simulated data and apply it in two case studies to reveal language contact in South America and the Balkans. Our results are supported by findings from previous studies. While we focus on detecting language contact, the method can also be used to uncover other traces of shared history in cultural evolution, and more generally, to reveal latent spatial clusters in the presence of confounders.     

Intermixing of InP-based multiple quantum wells for integrated optoelectronic devices

The intermixing characteristics of three widely used combinations of InP-based quantum wells (QW) are investigated using the impurity-free vacancy disordering (IFVD) technique. We demonstrate that the bandgap energy shift is highly dependent on the concentration gradient of the as-grown wells and barriers, as well as the thickness of the well, with thinner wells more susceptible to interdiffusion at the interface between the barrier and well. According to our results, the InGaAsP/InGaAsP and InGaAs/InP are well suited for applications requiring a wide range of bandgap values within the same wafer. In the case of the InGaAs/InGaAsP system, its use is limited due to the significant broadening of the photoluminescence spectrum that was observed. The effect of the top InGaAs layer over the InP cladding is also investigated, which leads to a simple way to obtain three different bandgaps in a single intermixing step.     

Standsicherheitsnachweis für Oberflächenabdichtungssysteme von Deponien

Verification of slope stability of surface sealing systems of landfill structures. According to national and european standards slope stability of capping systems should be verified with the concept of partial safety factors. The revised german recommendation E 2‐7 “Analysis of planar surface failure in lining systems” of the TC “Geotechnics of Landfill Structures” requires design approach 3, where actions are treated as geotechnical actions and partial safety factors are applied to the shear resistance of the soil in the potential slip surfaces. The tension force of a geogrid in case of reinforcement should be designed according to this approach. The paper describes the different failure modes of rupture and excessive deformations, the fundamentals of the verification procedure with partial safety factors, the limit state conditions in infinite slope analysis of stratified final capping systems as well as the design of reinforced structures. Hence, central point of the analysis is less the method of calculation as rather the determination of the effective shear parameters, which can be mobilised for a long period of time considering changing conditions and material ageing effects in the contact plane of the system.     

Texturing Internal Surfaces from a Few Cross Sections

We introduce a new appearance-modeling paradigm for synthesizing the internal structure of a 3D model from photographs of a few cross-sections of a real object. When the internal surfaces of the 3D model are revealed as it is cut, carved, or simply clipped, we synthesize their texture from the input photographs. Our texture synthesis algorithm is best classified as a morphing technique, which efficiently outputs the texture attributes of each surface point on demand. For determining source points and their weights in the morphing algorithm, we propose an interpolation domain based on BSP trees that naturally resembles planar splitting of real objects. In the context of the interpolation domain, we define efficient warping and morphing operations that allow for real-time synthesis of textures. Overall, our modeling paradigm, together with its realization through our texture morphing algorithm, allow users to author 3D models that reveal highly realistic internal surfaces in a variety of artistic flavors.     

Laparoscopic subtotal cholecystectomy

Subtotal cholecystectomy is a definitive and safe operation to treat diseases of the gallbladder, whenever there are major difficulties in dissection from the liver. Described herein is successful experience with 6 patients using this technique, through the laparoscopic approach. In cases with severe inflammatory changes, gallbladder embedded in liver tissue, and liver cirrhosis, they enabled reduction of operative time and avoidance of excessive bleeding that could have caused the conversion of the laparoscopic approach to open laparotomy.