Quantum phenomena in field-effect-controlled semiconductornanostructures

Quantum effects resulting from sub-100 nm features in planar, field-effect-controlled semiconductor structures or devices are discussed, and experimental results are compared with calculations. These devices are based on the GaAs-AlGaAs modulation-doped field-effect transistor (MODFET) and include grating-gate lateral surface superlattices. (LSSLs), grid-gate LSSLs, planar-resonant-tunneling field-effect transistors (PRESTFETs), multiple parallel quantum wires (MPQWs), and arrays of quantum dots (QDs). In contrast to conventional, epitaxially grown vertical quantum structures, planar structures offer the opportunity for electron confinement in three, two, and one dimensions and the flexibility of electrical tuning of quantum effects     

Physiological behavior and quality traits during fruit growth and ripening of four Amazonic hot pepper accessions

BACKGROUND: Skin color, acid content and changes in other chemical components have been developed as indicators of maturation in fruits of the Capsicum type. RESULTS: Fruit growth and ripening in four hot pepper accessions (CS) from C. frutescens (CS376) and from C. annuum (CS219, CS049 and CS032) were monitored in three commercial Colombian Amazonic orchards. The time between fruit setting and commercial pepper fruit maturity was 41 ± 5 days for CS219, while CS032, CS049 and CS376 required 47 ± 3 days. Three stages of development were identified. The first stage was cell division in the accessions and a transient peak in respiration rate in CS049. A second stage of fruit growth occurred due to maximum cell expansion and some transient peaks of respiration rate also took place. Finally, a plateau occurred as fruit reached full maturity and followed typical non‐climacteric behavior. CS032 and CS219 were pungent with increasing levels of alkaloids (capsaicin and dihydrocapsaicin) during fruit growth, although CS376 with its constant and higher levels of the former capsaicinoids early in fruit growth was not pungent, and neither was CS049. Morphological traits and fresh and dry weight together with color coordinates could be used to discriminate among accessions as revealed by two axes of the canonical discriminant analysis (99.9% total variance explained). CONCLUSIONS: In general, the time from fruit set and the apex skin color changes and accompanying morphological traits, were reasonable indicators of maturity in Amazonian hot pepper fruits. Multivariate analysis was able to discriminate among accessions. Copyright © 2008 Society of Chemical Industry     

SEL: A unified algorithm for salient entity linking

The entity linking task consists in automatically identifying and linking the entities mentioned in a text to their uniform resource identifiers in a given knowledge base. This task is very challenging due to its natural language ambiguity. However, not all the entities mentioned in the document have the same utility in understanding the topics being discussed. Thus, the related problem of identifying the most relevant entities present in the document, also known as salient entities (SE), is attracting increasing interest. In this paper, we propose salient entity linking, a novel supervised 2‐step algorithm comprehensively addressing both entity linking and saliency detection. The first step is aimed at identifying a set of candidate entities that are likely to be mentioned in the document. The second step, besides detecting linked entities, also scores them according to their saliency. Experiments conducted on 2 different data sets show that the proposed algorithm outperforms state‐of‐the‐art competitors and is able to detect SE with high accuracy. Furthermore, we used salient entity linking for extractive text summarization. We found that entity saliency can be incorporated into text summarizers to extract salient sentences from text. The resulting summarizers outperform well‐known summarization systems, proving the importance of using the SE information.     

Vision-based Control of a Delta Parallel Robot via Linear Camera-Space Manipulation

One of the open problems to control a parallel robot in real-time is the larger number of parameters to be incorporated in the control model when compared to serial robots. This paper presents an innovative vision-based method to control a delta-type parallel robot based on Linear Camera-Space Manipulation. The proposed method is a simple and robust technique capable of achieving real-time control of robots without relying on the calibration of either the robot or the environment parameters. To document the robustness of this technique, a sensitivity analysis was performed in simulation where the effect of two sources of error on the end-point positioning are considered. Such sources are the variability of each link’s parameters, and the uncertainty of the visual measurements. Experimental results on a Clavel’s delta parallel robot show that end-point positioning errors obtained with Linear Camera-Space Manipulation are less than 1.5 mm, demonstrating a low sensitivity to parameter uncertainty in qualitative agreement with the simulation results. The results show that the developed approach is advantageous to control parallel robots for industrial applications in real-time and can obviate to a number of open problems common with the control of parallel robots.     

Structural damage accumulation and control for life cycle optimum seismic performance of buildings

Seismic reliability and expected performance functions of structural systems are sensitive to the process of damage accumulation associated with the random sequences of ground motion excitations that those systems may experience. Optimum life cycle-based engineering decisions must examine the influence of concepts related to both the target safety level of the initial system and the eventual repair and maintenance actions that may be undertaken during the life of the system. This study includes an overview of the general framework supporting these decisions as well as some available results about (a) the influence of damage accumulation of the seismic vulnerability functions of building structures, (b) approximate estimates of accumulated damage and (c) optimum damage threshold values for repair of structural frames or replacement of energy dissipating devices. Some comments are presented concerning desirable studies about life cycle optimisation of systems exposed to different types of excitations.