Object Model Framework for Interface Modeling and IT-Oriented Interface Management

The intense complexity of interfaces in a construction project makes information technology (IT) applications a must for effective interface management (IM). This largely requires a unified, accurate, and efficient way of modeling interface information. Conventionally, interfaces are simply modeled as dependencies/relationships between project entities; various interface information is loosely presented in different ways, which reduces the accuracy and completeness of interface information as well as the efficiency in information exchange and application. This paper introduces an object view of interfaces and its inherent interface object modeling technique, and then presents an interface object model (IOM) framework. The IOM is the first in the literature that aims to systematically define the data structure and dependencies of interface information for modeling. It is at the core of a conceptually proposed systematic model-based IM strategy. When fully developed, the IOM can be used to accurately model multiple types of interfaces. This will greatly enhance the quality and interoperability of interface information, promote IT applications for IM, and ultimately improve interface-related project performance.     

Normal State Resistivity of Underdoped YBa2Cu3Ox Thin Films and La2-xSrxCuO4 Ultra-Thin Films under Epitaxial Strain

The normal state resistivity of high temperature superconductors can be probed in the region below T _c by suppressing the superconducting state in high magnetic fields. Here we present the normal state properties of YBa ₂ Cu ₃ O _x thin films in the underdoped regime and the normal state resistance of La _2-x Sr _x CuO ₄ thin films under epitaxial strain, measured below T _c by applying pulsed fields up to 60 T. We interpret these data in terms of the recently proposed 1D quantum transport model with the 1D paths corresponding to the charge stripes.     

Maillard glycation of β‐lactoglobulin induces conformation changes

Glycation by the Maillard reaction is an ubiquitous reaction of condensation of a reducing sugar with amino groups of proteins, which products could improve the functional and/or biological properties for food and non‐food uses. It can induce structural modifications in proteins, modifying their properties. The aim of this work was to investigate the association behavior and the conformational changes of β‐lactoglobulin (BLG) after its glycation by the Maillard reaction with several alimentary sugars (arabinose, galactose, glucose, lactose, rhamnose and ribose). Protein samples were heated in the presence or in the absence (heated control) of different sugars during 3 days at 60°C. Glycation induced oligomerization of BLG monomers. Depending on the reactivity of the sugar, the population of produced oligomers showed smaller or greater heterogeneity in molecular masses. Analysis of modified BLG by circular dichroism and by its susceptibility to pepsinolysis showed that the conditions of heating used did not significantly alter the conformation of BLG. Heating of BLG in presence of sugars induced only minor structural modification, when using the less reactive sugars such as lactose and rhamnose. It was, however, at the origin of major three‐dimensional destructuring in the case of the more reactive sugars such as arabinose and ribose. Pepsinolysis of glycated BLG did not affect about 62 and 35% of the protein molecules modified with lactose or rhamnose, and arabinose or ribose, respectively. The increase of susceptibility of glycated BLG to pepsinolysis could be related to the alteration of the conformation of the protein when glycation was performed with highly reactive sugars, as observed by circular dichroism and calorimetry analysis.     

Describing non-deterministic reactive systems by means of regular expressions

This paper presents a language based on regular expressions for describing non-deterministic reactive systems. It also presents some ideas on how to build (or adapt) tools for exploiting such a language (recognizers, generators and provers).     

Ausscheidungsvorgänge während der Wärmebehandlung kupferhaltiger Stähle

Kupferzusätze in Stahl können in bezug auf Korrosionswiderstand und Festigkeit vorteilhaft sein. Es wurde der Einfluß von Kupfer auf die Korngröße, mechanische Eigenschaften und Mikrostruktur von quasi-binären Fe-Cu-Legierungen ermittelt. Der Verfestigungseffekt von Kupfer im abgeschreckten Stahl entsteht durch Kornverfeinerung, Mischkristallverfestigung (46 N/mm²/(% Cu)) und eventuell durch Ausscheidung von Kupfer während des Abkühlens. Es gilt einen linearen Zusammenhang zwischen Korngröße und Kupfergehalt. Zwischen einigen mechanischen Eigenschaften (Härte, Zugfestigkeit und Streckgrenze) und dem Kupfergehalt gilt aber nur ein linearer Zusammenhang, wenn keine Cu-Ausscheidung während des Abkühlens nach dem Lösungsglühen stattgefunden hat. Die eventuell auftretende Ausscheidungshärtung während der Abkühlung kann eine Erhöhung der Streckgrenze mit bis zu 130 N/mm² bewirken. Das Auftreten einer Ausscheidung während des Abkühlens wurde elektronenmikroskopisch nachgewiesen. Der theoretische Verfestigungsbeitrag wurde mit Hilfe dieser Messungen berechnet und stimmt gut mit den Ergebnissen überein. Mittels Jominy-Versuchen wurde die notwendige Abkühlungsgeschwindigkeit zur Vermeidung einer Ausscheidung wie folgt bestimmt: ln(Abk. Geschw.) [°C/s] = 1,98 · (% Cu) ? 0,08.     

Shape from shadows.

The colors, textures, and shapes of shadows are physically constrained in several ways in natural scenes. The visual system appears to ignore these constraints, however, and to accept many patterns as shadows even though they could not occur naturally. In the stimuli that we have studied, the only requirements for the perception of depth due to shadows were that shadow regions be darker than the surrounding, nonshadow regions and that there be consistent contrast polarity along the shadow border. Three-dimensional shape due to shadows was perceived when shadow areas were filled with colors or textures that could not occur in natural scenes, when shadow and nonshadow regions had textures that moved in different directions, or when they were presented on different depth planes. The results suggest that the interpretation of shadows begins with the identification of acceptable shadow borders by a cooperative process that requires consistent contrast polarity across a range of scales at each point along the border. Finally, we discuss how the identification of a shadow region can help the visual system to patch together areas that are separated by shadow boundaries, to identify directions of surface curvature, and to select a preferred three-dimensional interpretation while rejecting others. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling safety and airworthiness (RTCA DO-178B) information: conceptual model and UML profile

Several safety-related standards exist for developing and certifying safety-critical systems. System safety assessments are common practice and system certification according to a standard requires submitting relevant system safety information to appropriate authorities. The RTCA DO-178B standard is a software quality assurance, safety-related standard for the development of software aspects of aerospace systems. This research introduces an approach to improve communication and collaboration among safety engineers, software engineers, and certification authorities in the context of RTCA DO-178B. This is achieved by utilizing a Unified Modeling Language (UML) profile that allows software engineers to model safety-related concepts and properties in UML, the de facto software modeling standard. A conceptual meta-model is defined based on RTCA DO-178B, and then a corresponding UML profile, which we call SafeUML, is designed to enable its precise modeling. We show how SafeUML improves communication by, for example, allowing monitoring implementation of safety requirements during the development process, and supporting system certification per RTCA DO-178B. This is enabled through automatic generation of safety and certification-related information from UML models. We validate this approach through a case study on developing an aircraft’s navigation controller subsystem.     

An optimization-based approach to the interpretation of single line drawings as 3D wire frames

Line drawings provide an effective means of communication about the geometry of 3D objects. An understanding of how to duplicate the way humans interpret line drawings is extremely important in enabling man-machine communication with respect to images, diagrams, and spatial constructs. In particular, such an understanding could be used to provide the human with the capability to create a line-drawing sketch of a polyhedral object that the machine can automatically convert into the intended 3D model.A recently published paper (Marill 1991) presented a simple optimization procedure supposedly able to duplicate human judgment in recovering the 3D wire frame geometry of objects depicted in line drawings. Marill provided some impressive examples, but no theoretical justification for his approach. Here, we introduce our own work by first critically examining Marill's algorithm. We provide an explanation for why Marill's algorithm was able to perform as well as it did on the examples he presented, discuss its weaknesses, and show very simple examples where it fails. We then provide an algorithm that improves on Marill's results. In particular, we show that an effective objective function must favor both symmetry and planarity-Marill deals only with the symmetry issue. By modifying Marill's objective function to explicitly favor planar-faced solutions, and by using a more competent optimization technique, we were able to demonstrate significantly improved performance in all of the examples Marill provided and those additional ones we constructed ourselves. Finally, we examine some questions relevant to the implications of this work for understanding the human ability to interpret line drawings.     

Mechanism of self-discharge in graphite-lithium anode

In order to evaluate the anode contribution to the lithium-ion battery self-discharge, three electrode coin cells composed of metallic lithium as reference and counter electrode, organic liquid electrolyte and graphite composite working electrode were constructed as test cells. They were first cycled for a dozen cycles and then stored in the full lithiated state of graphite, at 70 °C for periods from 1 to 8 days. The capacity loss was determined during the first delithiation following storage. The latter was found composed of two terms, a reversible and an irreversible one, where the relative amounts are storage time dependants. Electrochemical impedance spectroscopy (EIS) was used to investigate the changes in the cell interfacial characteristics. A model involving the formation of an absorbed electron-ion-electrolyte complex on the graphite surface is proposed as the mechanism of the reversible and irreversible capacity losses. It is also suggested that precipitation/dissolution reactions are taking place at the solid electrolyte interphase (SEI). Precipitation occurs with insoluble inorganic species such as, LiF and Li₂CO₃, whereas dissolution may concern the organic and/or polymer part of the SEI. The continuous growth of the inorganic (and most resistive) part of the SEI with the subsequent electrode isolation is proposed as the major mechanism of the electrode end of life.