Search results for "vertical"
showing 10 items of 417 documents
Microreflectivity studies of wavelength control in oxidised AlGaAs microcavities
2003
Wet oxidation of GaAs/AlGaAs structures is an important technique in the processing of advanced devices such as vertical cavity surface emitting lasers (VCSELs). In one VCSEL application, the low-index and electrically-insulating AlxOy layers have been used to obtain high-reflectivity and broad bandwidth distributed Bragg reflector mirrors (DBRs). A further recent development has shown that combined lateral–vertical oxidation of intracavity AlGaAs layers can be used to tune the resonant wavelength of a semiconductor microcavity. The slow oxidation rate limits the lateral scale of practical wet oxidation to mesas structures of 50–100 μm in width. Therefore post-processing assessment of spect…
Market entry decisions of US small and medium‐sized software firms
2008
PurposeThe purpose of this paper is to investigate market entry decisions of the US software SMEs by analyzing the impact of the most obvious factors (cultural distance, geographical distance, country risk, and three market size variables) in traditional internationalization theories to target country selection. By investigating the influence of these commonly cited macro‐level factors, this study proposes the best indicator for market entry decisions of the US small and medium‐sized software firms.Design/methodology/approachThis study uses a quantitative research approach applied to a sample of 100 US small and medium‐sized software firms.FindingsEmpirical findings in this study indicate t…
CitySearcher: A City Search Engine For Interests
2017
We introduce CitySearcher, a vertical search engine that searches for cities when queried for an interest. Generally in search engines, utilization of semantics between words is favorable for performance improvement. Even though ambiguous query words have multiple semantic meanings, search engines can return diversified results to satisfy different users' information needs. But for CitySearcher, mismatched semantic relationships can lead to extremely unsatisfactory results. For example, the city Sale would incorrectly rank high for the interest shopping because of semantic interpretations of the words. Thus in our system, the main challenge is to eliminate the mismatched semantic relationsh…
An experimental investigation on natural convection of air in a vertical channel
1993
Abstract The free convection of air in a vertical channel is studied experimentally in a laboratory model of height H = 2.6 m and rectangular cross-section b × s , with b = 1.2 m and the channel width s variable. One of the channel walls is heated with a uniform heat flux. Tests are made with different values of channel gap and heating power ( s = 7.5, 12.5, 17 cm; q c = 48–317 W m −2 ). On the basis of the results two empirical formulae are found, giving Nu and Re as functions of Ra and the geometrical parameter s/H ; Nu = 0.9282 Ra 0.2035 (s/H) 0.8972 ; Re = 0.5014 Ra 0.3148 (s/H) 0.418 . The mathematical form of these relationships reproduces other previously published formulae, valid fo…
Intermediate Isolation System with Nonlinear Lower Structure and Isolation System
2023
This paper reports a study on the Intermediate Isolation System (IIS) applied to existing buildings. This kind of application is particularly suitable when a vertical addition is planned for buildings in seismic zones; in such a case, an isolation system can be placed at the base of the extension to prevent the increase, or, better, to reduce the seismic demand on the existing structure. In previous works, parametric response spectrum analyses have been carried out on lumped mass models by varying the period of the isolation system. As a result, a sort of IIS design spectrum has been derived and used for selecting design solutions for the vertical extension that minimize the overall seismic…
Using skeleton and Hough transform variant to correct skew in historical documents
2020
International audience; As a main part of several document analysis systems, Skew estimation represents one of the major research challenges, particularly in case of historical documents exploration. In this paper, we propose an original skew angle detection and correction technique. Morphological Skeleton is introduced to considerably diminish the amount of data by eliminating the redundant pixels and preserving only the central curves of the image components. Next, the proposed method uses Progressive Probabilistic Hough Transform (PPHT) to find image lines. At the end, a specific procedure is applied in order to measure the global skew angle of the document image from these identified li…
Hydrothermal fluid venting in the offshore sector of Campi Flegrei caldera: A geochemical, geophysical, and volcanological study
2016
The ongoing unrest at the Campi Flegrei caldera (CFc) in southern Italy is prompting exploration of its poorly studied offshore sector. We report on a multidisciplinary investigation of the Secca delle Fumose (SdF), a submarine relief known since antiquity as the largest degassing structure of the offshore sector of CFc. We combined high-resolution morphobathymetric and seismostratigraphic data with onshore geological information to propose that the present-day SdF morphology and structure developed during the initial stages of the last CFc eruption at Monte Nuovo in AD 1538. We suggest that the SdF relief stands on the eastern uplifted border of a N-S-trending graben-like structure formed …
Investigating effects in GNSS station coordinate time series
2014
The vertical and horizontal displacements of the Earth can be measured to a high degree of precision using GNSS. Time series of Latvian GNSS station positions of both the EUPOS®-Riga and LatPos networks have been developed at the Institute of Geodesy and Geoinformation of the University of Latvia (LU GGI). In this study the main focus is made on the noise analysis of the obtained time series and site displacement identification. The results of time series have been analysed and distinctive behaviour of EUPOS®-Riga and LatPos station coordinate changes have been identified. The possible dependences of GNSS station coordinate distribution on EPN station problems, seismic activity of some area…
La integraciin vertical hacia atrrs y la rentabilidad econnmica de las empresas manufactureras (Backward Vertical Integration and Economic Profitabil…
2015
Spanish Abstract: El objetivo de este trabajo es analizar la relacion que existe entre la rentabilidad economica de las empresas manufactureras y la integracion vertical, asi como conocer cuales son las caracteristicas que determinan que una empresa tome la decision de integrarse verticalmente. De los resultados obtenidos podemos destacar los siguientes aspectos: en primer lugar, la integracion vertical de las empresas de la industria agroalimentaria es determinante de la rentabilidad economica y; en segundo lugar, tambien hemos comprobado la existencia de una relacion directa entre la integracion vertical y la especificidad, mostrando que las empresas con productos y activos mas especifico…
Development of the One Centimeter Accuracy Geoid Model of Latvia for GNSS Measurements
2015
There is an urgent necessity for a highly accurate and reliable geoid model to enable prompt determination of normal height with the use of GNSS coordinate determination due to the high precision requirements in geodesy, building and high precision road construction development. Additionally, the Latvian height system is in the process of transition from BAS- 77 (Baltic Height System) to EVRS2007 system. The accuracy of the geoid model must approach the precision of about ~1 cm looking forward to the Baltic Rail and other big projects. The use of all the available and verified data sources is planned, including the use of enlarged set of GNSS/levelling data, gravimetric measurement data and…