A Spatial Decision Support System for Property Valuation

May 6-

Skills and wage inequality in Greece: evidence from matched employer-employee data, 1995-2002

This paper examines changes in the Greek wage distribution over 1995-2002 and the role of skills in these changes using a matched employer-employee data set. This data set enables us to account for firm heterogeneity and obtain a more refined picture of the impact of skills. The methodology adopted is the Machado-Mata decomposition technique, which separates the part of wage changes that is due to changes in the job/employer and employee characteristics from the part due to changes in the returns to these characteristics. Our results indicate that the role of skills has been decisive. The skill return effects in combination with the composition effects of tenure, which are arguably responsive to economic developments and market conditions, have had an important contribution to the changes in the Greek wage distribution. On the other hand, the impact of predetermined demographic changes, as those captured by the age and education composition effects, has been relatively milder. JEL Classification: J31quantile regression, Returns to skill, Wage inequality

Markups in the euro area and the US over the period 1981-2004: a comparison of 50 sectors

This paper provides estimates of price-marginal cost ratios or markups for 50 sectors in 8 euro area countries and the US over the period 1981-2004. The estimates are obtained applying the methodology developed by Roeger (1995) on the EU KLEMS March 2007 database. Five stylized facts are derived. First, perfect competition can be rejected for almost all sectors in all countries; markup ratios are generally larger than 1. Second, average markups are heterogenous across countries. Third, markups are heterogeneous across sectors, with services having higher markups on average than manufacturing. Fourth, services sectors generally have higher markups in the euro area than the US, whereas the pattern is the reverse for manufacturing. Fifth, there is no evidence that there is a broad range change in markups from the eighties to the nineties. JEL Classification: D3, L11marginal cost, markup, price

Skills and wage inequality in Greece: evidence from matched employer-employee data, 1995-2002

This paper examines changes in the Greek wage distribution over 1995-2002 and the role of skills in these changes using a matched employer-employee data set. This data set enables us to account for firm heterogeneity and obtain a more refined picture of the impact of skills. The methodology adopted is the Machado-Mata decomposition technique, which separates the part of wage changes that is due to changes in the job/employer and employee characteristics from the part due to changes in the returns to these characteristics. Our results indicate that the role of skills has been decisive. The skill return effects in combination with the composition effects of tenure, which are arguably responsive to economic developments and market conditions, have had an important contribution to the changes in the Greek wage distribution. On the other hand, the impact of predetermined demographic changes, as those captured by the age and education composition effects, has been relatively milder.Returns to skill; Wage inequality; Quantile regression

Национална перспектива и интернационалне нити постмодернизма на Петој грчкој недељи савремене музике

The Fifth Hellenic Week of Contemporary Music (Athens, 1976) has been mainly considered in the context of a major political event: the fall of the military dictatorship in 1974. However, it may also be seen as a landmark for the transition to a postmodern era in Greece. The musical works presented during the Week, as well as their reception by the musical community are indicative of this transition. This paper aims at exploring those two perspectives and places the emphasis on the second, through an analytical comment on Le Tricot Rouge by Giorgos Kouroupos and the critiques in the press.Пета грчка недеља савремене музике одржана је 1976. године у Атини. Рецепција авангардних дела, која су се налазила у средишту претходних издања овог фестивала, драматично се променила — од полемичког и/или ентузијастичног става присутног у претходним издањима, до мирнијег и критичнијег става у Петој седмици. Ова значајна промена повезана је с националним политичким и идеолошким разлозима. Међутим, у ширем европском контексту ова промена може указивати и на прелазак са модернистичког на постмодернистичко схватање. Овај рад има за циљ да истражи како две различите перспективе могу утицати на конструкцију значења тих музичких догађаја и ставља акценат на „денационализовану” перспективу, која у први план истиче директнију везу од периферије ка харизматичним центрима. С једне стране, из националне перспективе, поменута промена повезана је са војном диктатуром која је успостављена у Грчкој 1967. године, а укинута 1974. године (Leotsakos 1976). Стога су и композиције поручене од грчких композитора и њихова рецепција током Четврте недеље представљале директне или индиректне изразе протеста против диктаторског режима (Tsagkarakis 2013). С друге стране, напор грчке „прогресивне” музичке заједнице да равноправно комуницира са интернационалном авангардом довео је, најпре, до присвајања постмодерних техника у музичким делима, а затим и до прихватања и мирног сапостојања неколико трендова. Овакав став је очигледан у реакцијама публике током Пете седмице. Последично, Пета недеља се може посматрати у светлу свеопштих промена у Грчкој и Европи тога доба (Romanou 1976, Christopoulou 2009, Samson 2013). У овом контексту, овај рад ће се фокусирати и на специфична музичка дела, посебно Le Tricot Rouge композитора Јоргоса Курупоса (Giorgos Kouroupos), као и на опште ставове музичке заједнице, укључујући ту композиторе, извођаче, публику и критичаре.Часопис је индексиран на http://doiserbia.nb.rs/, http://dais.sanu.ac.rs/handle/123456789/914 и у међународној бази ProQuest. / The journal is indexed in http://doiserbia.nb.rs/, http://dais.sanu.ac.rs/handle/123456789/914 and in the international database ProQuest. Издавање ове публикације подржали су Министарство културе и информисања Републике Србије, Министарство просвете, науке и технолошког развоја Републике Србије и СОКОЈ - Организација музичких аутора Србије / The publication of this volume was supported by the Ministry of Culture and Information of the Republic of Serbia, the Ministry of Education, Science and Technological Development of the Republic of Serbia and SOKOJ - Serbian Music Authors' Organizatio

Developing and applying efficient DD-vMCG method for nonadiabatic simulations

Gaussian wavepacket methods have been widely employed for the investigation of nonadiabatic molecular dynamics. The Direct Dynamics variational Multi-Configurational Gaussian (DD-vMCG) method provides a fully quantum mechanical solution to the time-dependent Schrödinger equation for the time evolution of nuclei with potential surfaces calculated on-the-fly using a quantum chemistry program. The first strand of this research study was to develop new, more efficient algorithms and improve the existing code for DD-vMCG aiming to increase both the accuracy and efficiency of this method. Thus, a new, efficient parallel algorithm to control the DD-vMCG database of quantum chemistry points is presented along with improvements to the interpolation scheme. Benchmark calculations on butatriene, allene and formamide showed that the new scheme is a very accurate, efficient and general method to employ for full-dimensional dynamics calculations. The aforementioned algorithm was then used to describe the photodissociation dynamics of phenol including all degrees of freedom, as the second strand of this research work was to explore more complex chemical systems. Full-dimensional quantum dynamics calculations including for the first time six electronic states, along with a detailed comparison with existing 3-state and 4-state models are presented. Including the fifth singlet excited state has been shown to be vital in unravelling the photodissociation of phenol. State population and flux analysis provided new insights into the decay mechanism of phenol confirming the idea of rapid relaxation to the ground state through the ¹ππ/1¹πσ* conical intersection. Finally, an effort to further improve the accuracy of DD-vMCG was made by employing a state-of-the-art approach where a Gaussian process regression scheme is introduced and machined-learned potential energy surfaces are obtained. All the findings suggest that this method could be promising to calculate potential energy surface matrix elements. However, further development is essential to take advantage of its benefits and to deal with the computational cost

Discovery of optical candidate supernova remnants in Sagittarius

During an [O III] survey for planetary nebulae, we identified a region in Sagittarius containing several candidate Supernova Remnants and obtained deep optical narrow-band images and spectra to explore their nature. The images of the unstudied area have been obtained in the light of Halpha+[N II], [S II] and [O III]. The resulting mosaic covers an area of 1.4x1.0 deg^2 where filamentary and diffuse emission was discovered, suggesting the existence of more than one supernova remnants (SNRs) in the area. Deep long slit spectra were also taken of eight different regions. Both the flux calibrated images and the spectra show that the emission from the filamentary structures originates from shock-heated gas, while the photo-ionization mechanism is responsible for the diffuse emission. Part of the optical emission is found to be correlated with the radio at 4850 MHz suggesting their association, while the WISE infrared emission found in the area at 12 and 22 micron marginally correlates with the optical. The presence of the [O III] emission line in one of the candidate SNRs suggests shock velocities into the interstellar "clouds" between 120 and 200 km/s, while the absence in the other indicates slower shock velocities. For all candidate remnants the [S II] 6716/6731 ratio indicates electron densities below 240 cm^{-3}, while the Halpha emission has been measured to be between 0.6 to 41x10^{-17} erg/s/cm^2/arcsec^2. The existence of eight pulsars within 1.5deg away from the center of the candidate SNRs also supports the scenario of many SNRs in the area as well as that the detected optical emission could be part of a number of supernovae explosions.Comment: 15 pages, 6 figures, accepted for publication in Astronomy & Astrophysic

A geographic knowledge discovery approach to property valuation

This thesis involves an investigation of how knowledge discovery can be applied in the area Geographic Information Science. In particular, its application in the area of property valuation in order to reveal how different spatial entities and their interactions affect the price of the properties is explored. This approach is entirely data driven and does not require previous knowledge of the area applied. To demonstrate this process, a prototype system has been designed and implemented. It employs association rule mining and associative classification algorithms to uncover any existing inter-relationships and perform the valuation. Various algorithms that perform the above tasks have been proposed in the literature. The algorithm developed in this work is based on the Apriori algorithm. It has been however, extended with an implementation of a ‘Best Rule’ classification scheme based on the Classification Based on Associations (CBA) algorithm. For the modelling of geographic relationships a graph-theoretic approach has been employed. Graphs have been widely used as modelling tools within the geography domain, primarily for the investigation of network-type systems. In the current context, the graph reflects topological and metric relationships between the spatial entities depicting general spatial arrangements. An efficient graph search algorithm has been developed, based on the Djikstra shortest path algorithm that enables the investigation of relationships between spatial entities beyond first degree connectivity. A case study with data from three central London boroughs has been performed to validate the methodology and algorithms, and demonstrate its effectiveness for computer aided property valuation. In addition, through the case study, the influence of location in the value of properties in those boroughs has been examined. The results are encouraging as they demonstrate the effectiveness of the proposed methodology and algorithms, provided that the data is appropriately pre processed and is of high quality