61 research outputs found
Quality externalities among hotel establishments: what is the impact of tour operators?
This paper is about quality decisions in a vertical structure where competitive producers sell to powerful retailers. Specifically, we focus the analysis on the role played by a tour operator (TO) on quality investments when distributing the capacity of a given tourist destination. We emphasize the presence of quality externalities among hotel establishments, and see that sometimes a TO distribution can provide a solution to the tragedy of the commons in qualityprovision. Thus, we analyze what implications do vertical relations have for quality in this industry, and then derive some policy recommendations. This paper is about quality decisions in a vertical structure where competitive producers sell to powerful retailers. Specifically, we focus the analysis on the role played by a tour operator (TO) on quality investments when distributing the capacity of a given tourist destination. We emphasize the presence of quality externalities among hotel establishments, and see that sometimes a TO distribution can provide a solution to the tragedy of the commons in qualityprovision. Thus, we analyze what implications do vertical relations have for quality in this industry, and then derive some policy recommendations
Influence of mismatch on the defects in relaxed epitaxial InGaAs/GaAs(100) films grown by molecular beam epitaxy
Thick (∼3 μm) films of InxGa1−xAs grown on GaAs(100) substrates, across the whole composition range, have been examined by transmission electron microscopy and double‐crystal x‐ray diffraction. The results were compared with the observed growth mode of the material determined by in situ reflection high‐energy electron diffraction in the molecular beam epitaxy growth system. The quality of the material degraded noticeably for compositions up to x∼0.5 associated with an increased density of dislocations and stacking faults. In contrast, improvements in quality as x approached 1.0 were correlated with the introduction of an increasingly more regular array of edge dislocations
First attempts to obtain a reference drift curve for traditional olive grove's plantations following ISO 22866
The current standard for the field measurements of spray drift (ISO 22866) is the only official standard for drift
measurements in field conditions for all type of crops, including bushes and trees. A series of field trials following
all the requirements established in the standard were arranged in a traditional olive grove in Córdoba (south of
Spain). The aims of the study were to evaluate the applicability of the current standard procedure to the particular conditions of traditional olive trees plantations, to evaluate the critical requirements for performing the tests
and to obtain a specific drift curve for such as important and specific crop as olive trees in traditional plantations,
considering the enormous area covered by this type of crop all around the world.The authors thank the Ministry of Economy and Competitiveness of the Spanish Government for their economic support through the pre-commercial procurement Mecaolivar project, financed with FEDER funds, and the AgVANCE project (AGL2013-48297-C2-1-R). The first author acknowledges the support of the Spanish Ministry of Education, Culture and SportPostprint (updated version
From Monolithic Satellites to the Internet of Satellites Paradigm: When Space, Air, and Ground Networks Become Interconnected
From the first satellite launched in 1957, these systems always have drawn the attention of telecommunications operators. Thanks to their natural orbit, satellites can provide coverage to the entire globe or serve a vast region. Is this feature that makes them potential systems to extend current ground networks over the space. The first satellites were conceived as a single backhaul system to broadcast television or phone calls. Over the years, this concept evolved to a group of satellites that compose a constellation to interconnect any user around the globe. Nowadays, these constellations are still evolving to massive architectures with thousands of satellites that are interconnected between them composing satellite networks. Additionally, with the emergence of 5G, the community has started to discuss how to integrate satellites in this infrastructure. A review of the evolution of the satellites for broadband communications is presented in this chapter, discussing the novel and future proposed architectures. The presented work concludes with the potential of these satellite systems to compose a hybrid and heterogeneous architecture in which space, air, and ground networks become interconnected
LFuji-air dataset: annotated 3D LiDAR point clouds of Fuji apple trees for fruit detection scanned under different forced air flow conditions
This article presents the LFuji-air dataset, which contains LiDAR based point clouds of 11 Fuji apples trees and the corresponding apples location ground truth. A mobile terrestrial laser scanner (MTLS) comprised of a LiDAR sensor and a real-time kinematics global navigation satellite system was used to acquire the data. The MTLS was mounted on an air-assisted sprayer used to generate different air flow conditions. A total of 8 scans per tree were performed, including scans from different LiDAR sensor positions (multi-view approach) and under different air flow conditions. These variability of the scanning conditions allows to use the LFuji-air dataset not only for training and testing new fruit detection algorithms, but also to study the usefulness of the multi-view approach and the application of forced air flow to reduce the number of fruit occlusions. The data provided in this article is related to the research article entitled 'Fruit detection, yield prediction and canopy geometric characterization using LiDAR with forced air flow' [1].This work was partly funded by the Secretaria d’Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya (grant 2017 SGR 646), the Spanish Ministry of Economy and Competitiveness (project AGL2013-48297-C2-2-R) and the Spanish Ministry of Science, Innovation and Universities (project RTI2018-094222-B-I00). The Spanish Ministry of Education is thanked for Mr. J. Gené's pre-doctoral fellowships (FPU15/03355). The work of Jordi Llorens was supported by the Spanish Ministry of Economy, Industry and Competitiveness through a postdoctoral position named Juan de la Cierva Incorporación (JDCI-2016-29464_N18003). We would also like to thank CONICYT FONDECYT 1171431 and CONICYT FB0008
Fruit detection in an apple orchard using a mobile terrestrial laser scanner
The development of reliable fruit detection and localization systems provides an opportunity to improve the crop value and management by limiting fruit spoilage and optimised harvesting practices. Most proposed systems for fruit detection are based on RGB cameras and thus are affected by intrinsic constraints, such as variable lighting conditions. This work presents a new technique that uses a mobile terrestrial laser scanner (MTLS) to detect and localise Fuji apples. An experimental test focused on Fuji apple trees (Malus domestica Borkh. cv. Fuji) was carried out. A 3D point cloud of the scene was generated using an MTLS composed of a Velodyne VLP-16 LiDAR sensor synchronised with an RTK-GNSS satellite navigation receiver. A reflectance analysis of tree elements was performed, obtaining mean apparent reflectance values of 28.9%, 29.1%, and 44.3% for leaves, branches and trunks, and apples, respectively. These results suggest that the apparent reflectance parameter (at 905 nm wavelength) can be useful to detect apples. For that purpose, a fourstep fruit detection algorithm was developed. By applying this algorithm, a localization success of 87.5%, an identification success of 82.4%, and an F1-score of 0.858 were obtained in relation to the total amount of fruits. These detection rates are similar to those obtained by RGB-based systems, but with the additional advantages of providing direct 3D fruit location information, which is not affected by sunlight variations. From the experimental results, it can be concluded that LiDAR-based technology and, particularly, its reflectance information, has potential for remote apple detection and 3D location.This work was partly funded by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya (grant 2017 SGR 646), the Spanish Ministry of Economy and Competitiveness (projects AGL2013-48297-C2-2-Rand MALEGRA, TEC2016-75976-R) and the Spanish Ministry of Science, Innovation and Universities (project RTI2018-094222-B-I00). The Spanish Ministry of Education is thanked for Mr. J. Gené’s pre-doctoral fellowships (FPU15/03355). The work of Jordi Llorens was supported by Spanish Ministry of Economy, Industry and Competitiveness through a postdoctoral position named Juan de la Cierva Incorporación (JDCI-2016-29464_N18003). We would also like to thank CONICYT/FONDECYT for grant 1171431 and CONICYT FB0008. Nufri (especially Santiago Salamero and Oriol Morreres) and Vicens Maquinària Agrícola S.A. are also thanked for their support during the data acquisition
Hydrogen-induced changes in the breakdown voltage of InP HEMTs
In this work, electrical measurements show that the breakdown voltage,BVDG, of InP HEMTs increases following exposure to H2. This BVDG shift is nonrecoverable. The increase in BVDG is found to be due to a decrease in the carrier concentration in the extrinsic portion of the device.We provide evidence that H2 reacts with the exposed InAlAs surface in the extrinsic region next to the gate, changing the underlying carrier concentration. Hall measurements of capped and uncapped HEMT samples show that the decrease in sheet carrier concentration can be attributed to a modification of the exposed InAlAs surface. Consistent with this, XPS experiments on uncapped heterostructures give evidence of As loss from the InAlAs surface upon exposure to hydrogen
Quality externalities among hotel establishments: what is the impact of tour operators?.
This paper is about quality decisions in a vertical structure where competitive producers sell to powerful retailers. Specifically, we focus the analysis on the role played by a tour operator (TO) on quality investments when distributing the capacity of a given tourist destination. We emphasize the presence of quality externalities among hotel establishments, and see that sometimes a TO distribution can provide a solution to the tragedy of the commons in qualityprovision. Thus, we analyze what implications do vertical relations have for quality in this industry, and then derive some policy recommendations. This paper is about quality decisions in a vertical structure where competitive producers sell to powerful retailers. Specifically, we focus the analysis on the role played by a tour operator (TO) on quality investments when distributing the capacity of a given tourist destination. We emphasize the presence of quality externalities among hotel establishments, and see that sometimes a TO distribution can provide a solution to the tragedy of the commons in qualityprovision. Thus, we analyze what implications do vertical relations have for quality in this industry, and then derive some policy recommendations.
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