54 resultados para OHMIC CONTACTS
Resumo:
Crear una aplicació i-CRM, el Customer Relationship Management és un sistema que permet a les empreses manejar tota la informació relativa als seus clients des d'una única plataforma de programari. L'esmentada aplicació tindrà una interfície Web, i una estructura multicapa, que pugui ser emprada des de qualsevol localització i el nombre d'usuaris no sigui una limitació. Bàsicament, consistirà en una aplicació on es puguin crear entitats comercials (clients i potencials), i mantenir la relació bàsica amb els mateixos, aquesta es restringirà als contactes comercials, incidències i campanyes de màrqueting relacional.
Resumo:
After centuries of lack of contacts between Spain and Portugal, the democratization of both countries allowed for a rapprochement which today is becoming more intensive. The crucial factor of the growing integration of Spanish and Portuguese border regions into a cross-border region is naturally the INTERREG programme. Both regions are disadvantaged within the European Union and their respective countries as poor regions. They have the status of a ‘double periphery’. In the 1980s and particularly 1990s actors on both sides of the border intensified their contacts in order to overcome their double peripherality. The growing number of projects, the improvement of infrastructures and the revival of associationism will certainly change the quality of life of these regions, which are still among the lowest in both countries. The continuation of the INTERREG programme after 2007-2013 will be an important consolidating tool for the further development of cross-border cooperation.
Resumo:
In this article we compare regression models obtained to predict PhD students’ academic performance in the universities of Girona (Spain) and Slovenia. Explanatory variables are characteristics of PhD student’s research group understood as an egocentered social network, background and attitudinal characteristics of the PhD students and some characteristics of the supervisors. Academic performance was measured by the weighted number of publications. Two web questionnaires were designed, one for PhD students and one for their supervisors and other research group members. Most of the variables were easily comparable across universities due to the careful translation procedure and pre-tests. When direct comparison was notpossible we created comparable indicators. We used a regression model in which the country was introduced as a dummy coded variable including all possible interaction effects. The optimal transformations of the main and interaction variables are discussed. Some differences between Slovenian and Girona universities emerge. Some variables like supervisor’s performance and motivation for autonomy prior to starting the PhD have the same positive effect on the PhD student’s performance in both countries. On the other hand, variables like too close supervision by the supervisor and having children have a negative influence in both countries. However, we find differences between countries when we observe the motivation for research prior to starting the PhD which increases performance in Slovenia but not in Girona. As regards network variables, frequency of supervisor advice increases performance in Slovenia and decreases it in Girona. The negative effect in Girona could be explained by the fact that additional contacts of the PhD student with his/her supervisor might indicate a higher workload in addition to or instead of a better advice about the dissertation. The number of external student’s advice relationships and social support mean contact intensity are not significant in Girona, but they have a negative effect in Slovenia. We might explain the negative effect of external advice relationships in Slovenia by saying that a lot of external advice may actually result from a lack of the more relevant internal advice
Resumo:
This paper studies the extent to which social networks influence the employment stability and wages of immigrants in Spain. By doing so, I consider an aspect that has not been previously addressed in the empirical literature, namely the connection between immigrants' social networks and labor market outcomes in Spain. For this purpose, I use micro-data from the National Immigrant Survey carried out in 2007. The analysis is conducted in two stages. First, the impact of social networks on the probability of keeping the first job obtained in Spain is studied through a multinomial logit regression. Second, quantile regressions are used to estimate a wage equation. The empirical results suggest that once the endogeneity problem has been accounted for, immigrants' social networks influence their labor market outcomes. On arrival, immigrants experience a mismatch in the labor market. In addition, different effects of social networks on wages by gender and wage distribution are found. While contacts on arrival and informal job access mechanisms positively influence women's wages, a wage penalty is observed for men.
Resumo:
El projecte Microscòpia d'alta resolució aplicada a anàlisis traceològiques, tafonòmiques y zooarqueològiques ha permès donar continuïtat i ampliar la xarxa científica posada en marxa gràcies a dos projectes PBR anteriors entre l’IPHES i quatre centres anglesos: l’Institute of Archaeology del University College of London, el Dept of Prehistory and Europe del British Museum, el Dept of Palaeontology del Natural History Museum, i el Lithic Microwear Research Laboratory de la University of Bradford. El tema tractat ha estat l’avaluació de la resolució i de la possible complementarietat de diferents tècniques avançades de microscòpia per a l’anàlisi de les superfícies d’ossos i eines de pedra prehistòriques: microscòpia òptica, electrònica (SEM i ESEM), microscòpia làser confocal (LSCM) i el sistema Alicona 3D Infinite Imaging. Les diverses accions de mobilitat entre Catalunya i el Regne Unit realitzades han permès satisfactòriament posar en comú els procediments emprats pels diferents especialistes de cada centre. Les proves realitzades sobre materials de jaciments arqueològics clau tant britànics com de l’estat espanyol han permès avaluar els avantatges i limitacions que cada tècnica presentava segons la mostra estudiada (eines de pedra, ossos, dents...) i segons els requeriments específics de l’estudi plantejat. En termes generals, s’ha posat en evidència que les diferents tècniques explorades són força complementàries. És a dir, la gran capacitat d’augments i de resolució d’imatge dels microscopis electrònics es complementa amb unes meravelloses prestacions quant anàlisi de textures, de perfils i de reconstrucció 3D dels altres aparells. La principal conclusió que podem extreure, doncs, és que l’estudi d’aquest tipus d’objectes arqueològics requereix de l’ús combinat de diferents aparells de microscòpia. Tant els treballs realitzats com els contactes entre especialistes establerts al llarg del projecte s’han plasmat ja en treballs concrets, alguns d’ells ja publicats o en fase final de publicació.
Resumo:
Many workers believe that personal contacts are crucial for obtainingjobs in high-wage sectors. On the other hand, firms in high-wage sectorsreport using employee referrals because they help provide screening andmonitoring of new employees. This paper develops a matching model thatcan explain the link between inter-industry wage differentials and useof employee referrals. Referrals lower monitoring costs because high-effortreferees can exert peer pressure on co-workers, allowing firms to pay lowerefficiency wages. On the other hand, informal search provides fewer job andapplicant contacts than formal methods (e.g., newspaper ads). In equilibrium,the matching process generates segmentation in the labor market becauseof heterogeneity in the size of referral networks. Referrals match good high-paying jobs to well-connected workers, while formal methods matchless attractive jobs to less-connected workers. Industry-level data show apositive correlation between industry wage premia and use of employeereferrals. Moreover, evidence using the NLSY shows similar positive andsignificant OLS and fixed-effects estimates of the returns to employeereferrals, but insignificant effects once sector of employment is controlledfor. This evidence suggests referred workers earn higher wages not becauseof higher unobserved ability or better matches but rather because theyare hired in high-wage sectors.
Resumo:
El projecte proposa un sistema d’entrenament per l’escalada, donant noves solucions adaptades a les noves tendències socials i de mercat. La millora en la comunicació usuari-producte i el seguiment del progrés en l’entrenament són les bases d’aquest projecte, entorn a les quals giren totes les solucions plantejades. Donat l’increment exponencial dels usuaris de sales d’entrenament i aficionats a l’escalada en els últims deu anys, on m’incloc, aquest projecte pretén donar una nova visió més real de l’entrenament, plantejant un producte versàtil i canviant, el qual s’adequa a les necessitats concretes de cada usuari, a l’hora que proposa diferents muntatges segons les possibilitats de l’espai d’instal·lació. L’interès personal per l’escalada i l’experiència durants els últims anys en sales d’entrenament m’han fet plantejar-me la funció de diferents elements dins d’aquests espais. L’ús de noves tecnologies i de sistemes de programació específics donen a l’usuari l’oportunitat d’endinsar-se en tota una experiència diferent d’entrenament, on pot dissenyar el seu propi pla, tenir un seguiment estadístic de la seva evolució i ser partícip d’una xarxa social de contactes, recomanacions, actualitzacions d’exercicis i plantejament de nous reptes. Naixent les sales d’entrenament a la dècada dels seixanta, avui dia són més de 40 les empreses dedicades a la producció i fabricació de material per elles. Només un 11% inverteixen en innovació i disseny i, tot i així, els resultats, en la majoria dels casos, no es desmarquen gaire d’allò que ja existeix. Amb aquest projecte es vol obrir un nou paradigma en el sector, donar la volta a allò existent i mostrar que fent un bon estudi de necessitats es poden plantejar solucions molt més reals, adaptables i personalitzables.
Resumo:
A frequency-dependent compact model for inductors in high ohmic substrates, which is based on an energy point-of-view, is developed. This approach enables the description of the most important coupling phenomena that take place inside the device. Magnetically induced losses are quite accurately calculated and coupling between electric and magnetic fields is given by means of a delay constant. The later coupling phenomenon provides a modified procedure for the computation of the fringing capacitance value, when the self-resonance frequency of the inductor is used as a fitting parameter. The model takes into account the width of every metal strip and the pitch between strips. This enables the description of optimized layout inductors. Data from experiments and electromagnetic simulators are presented to test the accuracy of the model.
Resumo:
Coulomb suppression of shot noise in a ballistic diode connected to degenerate ideal contacts is analyzed in terms of the correlations taking place between current fluctuations due to carriers injected with different energies. By using Monte Carlo simulations we show that at low frequencies the origin of Coulomb suppression can be traced back to the negative correlations existing between electrons injected with an energy close to that of the potential barrier present in the diode active region and all other carriers injected with higher energies. Correlations between electrons with energy above the potential barrier with the rest of electrons are found to influence significantly the spectra at high frequency in the cutoff region.
Resumo:
A general asymptotic analysis of the Gunn effect in n-type GaAs under general boundary conditions for metal-semiconductor contacts is presented. Depending on the parameter values in the boundary condition of the injecting contact, different types of waves mediate the Gunn effect. The periodic current oscillation typical of the Gunn effect may be caused by moving charge-monopole accumulation or depletion layers, or by low- or high-field charge-dipole solitary waves. A new instability caused by multiple shedding of (low-field) dipole waves is found. In all cases the shape of the current oscillation is described in detail: we show the direct relationship between its major features (maxima, minima, plateaus, etc.) and several critical currents (which depend on the values of the contact parameters). Our results open the possibility of measuring contact parameters from the analysis of the shape of the current oscillation.
Resumo:
A general formulation of boundary conditions for semiconductor-metal contacts follows from a phenomenological procedure sketched here. The resulting boundary conditions, which incorporate only physically well-defined parameters, are used to study the classical unipolar drift-diffusion model for the Gunn effect. The analysis of its stationary solutions reveals the presence of bistability and hysteresis for a certain range of contact parameters. Several types of Gunn effect are predicted to occur in the model, when no stable stationary solution exists, depending on the value of the parameters of the injecting contact appearing in the boundary condition. In this way, the critical role played by contacts in the Gunn effect is clearly established.
Resumo:
By an analysis of the exchange of carriers through a semiconductor junction, a general relationship for the nonequilibrium population of the interface states in Schottky barrier diodes has been derived. Based on this relationship, an analytical expression for the ideality factor valid in the whole range of applied bias has been given. This quantity exhibits two different behaviours depending on the value of the applied bias with respect to a critical voltage. This voltage, which depends on the properties of the interfacial layer, constitutes a new parameter to complete the characterization of these junctions. A simple interpretation of the different behaviours of the ideality factor has been given in terms of the nonequilibrium charging properties of interface states, which in turn explains why apparently different approaches have given rise to similar results. Finally, the relevance of our results has been considered on the determination of the density of interface states from nonideal current-voltage characteristics and in the evaluation of the effects of the interfacial layer thickness in metal-insulator-semiconductor tunnelling diodes.
Resumo:
A systematic method to improve the quality (Q) factor of RF integrated inductors is presented in this paper. The proposed method is based on the layout optimization to minimize the series resistance of the inductor coil, taking into account both ohmic losses, due to conduction currents, and magnetically induced losses, due to eddy currents. The technique is particularly useful when applied to inductors in which the fabrication process includes integration substrate removal. However, it is also applicable to inductors on low-loss substrates. The method optimizes the width of the metal strip for each turn of the inductor coil, leading to a variable strip-width layout. The optimization procedure has been successfully applied to the design of square spiral inductors in a silicon-based multichip-module technology, complemented with silicon micromachining postprocessing. The obtained experimental results corroborate the validity of the proposed method. A Q factor of about 17 have been obtained for a 35-nH inductor at 1.5 GHz, with Q values higher than 40 predicted for a 20-nH inductor working at 3.5 GHz. The latter is up to a 60% better than the best results for a single strip-width inductor working at the same frequency.
Resumo:
A general asymptotic analysis of the Gunn effect in n-type GaAs under general boundary conditions for metal-semiconductor contacts is presented. Depending on the parameter values in the boundary condition of the injecting contact, different types of waves mediate the Gunn effect. The periodic current oscillation typical of the Gunn effect may be caused by moving charge-monopole accumulation or depletion layers, or by low- or high-field charge-dipole solitary waves. A new instability caused by multiple shedding of (low-field) dipole waves is found. In all cases the shape of the current oscillation is described in detail: we show the direct relationship between its major features (maxima, minima, plateaus, etc.) and several critical currents (which depend on the values of the contact parameters). Our results open the possibility of measuring contact parameters from the analysis of the shape of the current oscillation.
Resumo:
A general formulation of boundary conditions for semiconductor-metal contacts follows from a phenomenological procedure sketched here. The resulting boundary conditions, which incorporate only physically well-defined parameters, are used to study the classical unipolar drift-diffusion model for the Gunn effect. The analysis of its stationary solutions reveals the presence of bistability and hysteresis for a certain range of contact parameters. Several types of Gunn effect are predicted to occur in the model, when no stable stationary solution exists, depending on the value of the parameters of the injecting contact appearing in the boundary condition. In this way, the critical role played by contacts in the Gunn effect is clearly established.