Adaptive Continuous time Markov Chain Approximation Model to General Jump-Diusions

We propose a non-equidistant Q rate matrix formula and an adaptive numerical algorithm for a continuous time Markov chain to approximate jump-diffusions with affine or non-affine functional specifications. Our approach also accommodates state-dependent jump intensity and jump distribution, a flexibility that is very hard to achieve with other numerical methods. The Kolmogorov-Smirnov test shows that the proposed Markov chain transition density converges to the one given by the likelihood expansion formula as in Ait-Sahalia (2008). We provide numerical examples for European stock option pricing in Black and Scholes (1973), Merton (1976) and Kou (2002).

A bayesian spatial individual effects probit model of the 2010 UK general election

The Conservative Party emerged from the 2010 United Kingdom General Election as the largest single party, but their support was not geographically uniform. In this paper, we estimate a hierarchical Bayesian spatial probit model that tests for the presence of regional voting effects. This model allows for the estimation of individual region-specic effects on the probability of Conservative Party success, incorporating information on the spatial relationships between the regions of the mainland United Kingdom. After controlling for a range of important covariates, we find that these spatial relationships are significant and that our individual region-specic effects estimates provide additional evidence of North-South variations in Conservative Party support.

The Impact of Population Ageing on the Labour Market: Evidence from Overlapping Generations Computable General Equilibrium (OLG-CGE) Model of Scotland

This paper presents a dynamic Overlapping Generations Computable General Equilibrium (OLG-CGE) model of Scotland. The model is used to examine the impact of population ageing on the labour market. More specifically, it is used to evaluate the effects of labour force decline and labour force ageing on key macro-economic variables. The second effect is assumed to operate through age-specific productivity and labour force participation. In the analysis, particular attention is paid to how population ageing impinges on the government expenditure constraint. The basic structure of the model follows in the Auerbach and Kotlikoff tradition. However, the model takes into consideration directly age-specific mortality. This is analogous to “building in” a cohort-component population projection structure to the model, which allows more complex and more realistic demographic scenarios to be considered.

The Impact of Population Ageing on the Labour Market: Evidence from Overlapping Generations Computable General Equilibrium (OLG-CGE) Model of Scotland

This paper presents a dynamic Overlapping Generations Computable General Equilibrium (OLG-CGE) model of Scotland. The model is used to examine the impact of population ageing on the labour market. More specifically, it is used to evaluate the effects of labour force decline and labour force ageing on key macro-economic variables. The second effect is assumed to operate through age-specific productivity and labour force participation. In the analysis, particular attention is paid to how population ageing impinges on the government expenditure constraint. The basic structure of the model follows in the Auerbach and Kotlikoff tradition. However, the model takes into consideration directly age-specific mortality. This is analogous to “building in” a cohort-component population projection structure to the model, which allows more complex and more realistic demographic scenarios to be considered.

A general model to predict individual exposure to solar UV by using ambient irradiance data

Excessive exposure to solar ultraviolet (UV) is the main cause of skin cancer. Specific prevention should be further developed to target overexposed or highly vulnerable populations. A better characterisation of anatomical UV exposure patterns is however needed for specific prevention. To develop a regression model for predicting the UV exposure ratio (ER, ratio between the anatomical dose and the corresponding ground level dose) for each body site without requiring individual measurements. A 3D numeric model (SimUVEx) was used to compute ER for various body sites and postures. A multiple fractional polynomial regression analysis was performed to identify predictors of ER. The regression model used simulation data and its performance was tested on an independent data set. Two input variables were sufficient to explain ER: the cosine of the maximal daily solar zenith angle and the fraction of the sky visible from the body site. The regression model was in good agreement with the simulated data ER (R(2)=0.988). Relative errors up to +20% and -10% were found in daily doses predictions, whereas an average relative error of only 2.4% (-0.03% to 5.4%) was found in yearly dose predictions. The regression model predicts accurately ER and UV doses on the basis of readily available data such as global UV erythemal irradiance measured at ground surface stations or inferred from satellite information. It renders the development of exposure data on a wide temporal and geographical scale possible and opens broad perspectives for epidemiological studies and skin cancer prevention.

A general continuous auction model with insiders

We analyse in a unified way how the presence of a trader with privilege information makes the market to be efficient when the release time is known. We establish a general relation between the problem of finding an equilibrium and the problem of enlargement of filtrations. We also consider the case where the time of announcement is random. In such a case the market is not fully efficient and there exists equilibrium if the sensitivity of prices with respect to the global demand is time decreasing according with the distribution of the random time.

General preferences for consumption goods in the random matching model of commodity money

This paper generalizes the original random matching model of money byKiyotaki and Wright (1989) (KW) in two aspects: first, the economy ischaracterized by an arbitrary distribution of agents who specialize in producing aparticular consumption good; and second, these agents have preferences suchthat they want to consume any good with some probability. The resultsdepend crucially on the size of the fraction of producers of each goodand the probability with which different agents want to consume eachgood. KW and other related models are shown to be parameterizations ofthis more general one.

Revenue management under general discrete choice model of consumer behavior

Customer choice behavior, such as 'buy-up' and 'buy-down', is an importantphe-nomenon in a wide range of industries. Yet there are few models ormethodologies available to exploit this phenomenon within yield managementsystems. We make some progress on filling this void. Specifically, wedevelop a model of yield management in which the buyers' behavior ismodeled explicitly using a multi-nomial logit model of demand. Thecontrol problem is to decide which subset of fare classes to offer ateach point in time. The set of open fare classes then affects the purchaseprobabilities for each class. We formulate a dynamic program todetermine the optimal control policy and show that it reduces to a dynamicnested allocation policy. Thus, the optimal choice-based policy caneasily be implemented in reservation systems that use nested allocationcontrols. We also develop an estimation procedure for our model based onthe expectation-maximization (EM) method that jointly estimates arrivalrates and choice model parameters when no-purchase outcomes areunobservable. Numerical results show that this combined optimization-estimation approach may significantly improve revenue performancerelative to traditional leg-based models that do not account for choicebehavior.

A Hull and White formula for a general stochastic volatility jump-diffusion model with applications to the study of the short-time behavior of the implied volatility

In this paper, generalizing results in Alòs, León and Vives (2007b), we see that the dependence of jumps in the volatility under a jump-diffusion stochastic volatility model, has no effect on the short-time behaviour of the at-the-money implied volatility skew, although the corresponding Hull and White formula depends on the jumps. Towards this end, we use Malliavin calculus techniques for Lévy processes based on Løkka (2004), Petrou (2006), and Solé, Utzet and Vives (2007).

KCM, a general framework for codon-based model of evolution

With the advancement of high-throughput sequencing and dramatic increase of available genetic data, statistical modeling has become an essential part in the field of molecular evolution. Statistical modeling results in many interesting discoveries in the field, from detection of highly conserved or diverse regions in a genome to phylogenetic inference of species evolutionary history Among different types of genome sequences, protein coding regions are particularly interesting due to their impact on proteins. The building blocks of proteins, i.e. amino acids, are coded by triples of nucleotides, known as codons. Accordingly, studying the evolution of codons leads to fundamental understanding of how proteins function and evolve. The current codon models can be classified into three principal groups: mechanistic codon models, empirical codon models and hybrid ones. The mechanistic models grasp particular attention due to clarity of their underlying biological assumptions and parameters. However, they suffer from simplified assumptions that are required to overcome the burden of computational complexity. The main assumptions applied to the current mechanistic codon models are (a) double and triple substitutions of nucleotides within codons are negligible, (b) there is no mutation variation among nucleotides of a single codon and (c) assuming HKY nucleotide model is sufficient to capture essence of transition- transversion rates at nucleotide level. In this thesis, I develop a framework of mechanistic codon models, named KCM-based model family framework, based on holding or relaxing the mentioned assumptions. Accordingly, eight different models are proposed from eight combinations of holding or relaxing the assumptions from the simplest one that holds all the assumptions to the most general one that relaxes all of them. The models derived from the proposed framework allow me to investigate the biological plausibility of the three simplified assumptions on real data sets as well as finding the best model that is aligned with the underlying characteristics of the data sets. -- Avec l'avancement de séquençage à haut débit et l'augmentation dramatique des données géné¬tiques disponibles, la modélisation statistique est devenue un élément essentiel dans le domaine dé l'évolution moléculaire. Les résultats de la modélisation statistique dans de nombreuses découvertes intéressantes dans le domaine de la détection, de régions hautement conservées ou diverses dans un génome de l'inférence phylogénétique des espèces histoire évolutive. Parmi les différents types de séquences du génome, les régions codantes de protéines sont particulièrement intéressants en raison de leur impact sur les protéines. Les blocs de construction des protéines, à savoir les acides aminés, sont codés par des triplets de nucléotides, appelés codons. Par conséquent, l'étude de l'évolution des codons mène à la compréhension fondamentale de la façon dont les protéines fonctionnent et évoluent. Les modèles de codons actuels peuvent être classés en trois groupes principaux : les modèles de codons mécanistes, les modèles de codons empiriques et les hybrides. Les modèles mécanistes saisir une attention particulière en raison de la clarté de leurs hypothèses et les paramètres biologiques sous-jacents. Cependant, ils souffrent d'hypothèses simplificatrices qui permettent de surmonter le fardeau de la complexité des calculs. Les principales hypothèses retenues pour les modèles actuels de codons mécanistes sont : a) substitutions doubles et triples de nucleotides dans les codons sont négligeables, b) il n'y a pas de variation de la mutation chez les nucléotides d'un codon unique, et c) en supposant modèle nucléotidique HKY est suffisant pour capturer l'essence de taux de transition transversion au niveau nucléotidique. Dans cette thèse, je poursuis deux objectifs principaux. Le premier objectif est de développer un cadre de modèles de codons mécanistes, nommé cadre KCM-based model family, sur la base de la détention ou de l'assouplissement des hypothèses mentionnées. En conséquence, huit modèles différents sont proposés à partir de huit combinaisons de la détention ou l'assouplissement des hypothèses de la plus simple qui détient toutes les hypothèses à la plus générale qui détend tous. Les modèles dérivés du cadre proposé nous permettent d'enquêter sur la plausibilité biologique des trois hypothèses simplificatrices sur des données réelles ainsi que de trouver le meilleur modèle qui est aligné avec les caractéristiques sous-jacentes des jeux de données. Nos expériences montrent que, dans aucun des jeux de données réelles, tenant les trois hypothèses mentionnées est réaliste. Cela signifie en utilisant des modèles simples qui détiennent ces hypothèses peuvent être trompeuses et les résultats de l'estimation inexacte des paramètres. Le deuxième objectif est de développer un modèle mécaniste de codon généralisée qui détend les trois hypothèses simplificatrices, tandis que d'informatique efficace, en utilisant une opération de matrice appelée produit de Kronecker. Nos expériences montrent que sur un jeux de données choisis au hasard, le modèle proposé de codon mécaniste généralisée surpasse autre modèle de codon par rapport à AICc métrique dans environ la moitié des ensembles de données. En outre, je montre à travers plusieurs expériences que le modèle général proposé est biologiquement plausible.

Anisotropic fluid with SU(2) type structure in general relativity: A model of localized matter

A model of anisotropic fluid with three perfect fluid components in interaction is studied. Each fluid component obeys the stiff matter equation of state and is irrotational. The interaction is chosen to reproduce an integrable system of equations similar to the one associated to self-dual SU(2) gauge fields. An extension of the BelinskyZakharov version of the inverse scattering transform is presented and used to find soliton solutions to the coupled Einstein equations. A particular class of solutions that can be interpreted as lumps of matter propagating in empty space-time is examined.

A general linear relaxometry model of R1 using imaging data.

PURPOSE: The longitudinal relaxation rate (R1 ) measured in vivo depends on the local microstructural properties of the tissue, such as macromolecular, iron, and water content. Here, we use whole brain multiparametric in vivo data and a general linear relaxometry model to describe the dependence of R1 on these components. We explore a) the validity of having a single fixed set of model coefficients for the whole brain and b) the stability of the model coefficients in a large cohort. METHODS: Maps of magnetization transfer (MT) and effective transverse relaxation rate (R2 *) were used as surrogates for macromolecular and iron content, respectively. Spatial variations in these parameters reflected variations in underlying tissue microstructure. A linear model was applied to the whole brain, including gray/white matter and deep brain structures, to determine the global model coefficients. Synthetic R1 values were then calculated using these coefficients and compared with the measured R1 maps. RESULTS: The model's validity was demonstrated by correspondence between the synthetic and measured R1 values and by high stability of the model coefficients across a large cohort. CONCLUSION: A single set of global coefficients can be used to relate R1 , MT, and R2 * across the whole brain. Our population study demonstrates the robustness and stability of the model. Magn Reson Med, 2014. © 2014 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. Magn Reson Med 73:1309-1314, 2015. © 2014 Wiley Periodicals, Inc.

Sopeutumattomien oppilaiden tunne- ja itsesäätelytaitojen kehittyminen: Oppilaiden ja opettajien arvioita ja kokemuksia Aggression portaat -interventiosta

Tässä tutkimuksessa tarkastellaan sopeutumattomien erityisoppilaiden tunne- ja itsesäätelytaitojen kehittymistä Aggression portaat -interventio-ohjelman avulla kolmen vuoden tutkimusjakson aikana. Käsite sopeutumaton oppilas ei ole yksiselitteisesti määriteltävissä, mutta tässä tutkimuksessa sillä tarkoitetaan yleisopetussuunnitelman mukaan opiskelevaa oppilasta, joka käyttäytymiseen ja tunne-elämään liittyvien haasteidensa vuoksi on saanut siirron erityisopetuksen oppilaaksi ja saa enintään 10 oppilaan opetusryhmässä erityistä pedagogista tukea. Tutkimuksen yksi keskeinen tehtävä oli tutkia, onko tunne- ja itsesäätelytaitojen opettamisesta hyötyä sopeutumattomien oppilaiden tunteiden hallinnan ja käyttäytymisen itsesäätelyn kannalta. Tutkimuksen teoreettisena viitekehyksenä on Rose-Krasnorin (1997) malli yksilön sosioemotionaalisesta kompetenssista täydennettynä muiden tutkijoiden näkemyksillä. Sosioemotionaalinen kompetenssi on yläkäsite, johon kuuluvat alakäsitteinä tunne- ja itsesäätelytaidot, sosiokognitiiviset taidot ja sosiaaliset taidot. Lisäksi sosioemotionaaliseen kompetenssiin vaikuttavat kiintymyssuhteet ja osallisuus sekä tavoitteet vuorovaikutuksessa ja konteksti. Tässä tutkimuksessa keskitytään tunne- ja itsesäätelytaitoihin. Interventioryhmän (N=36) muodostivat Varsinais-Suomen alueella opiskelevat sopeutumattomien oppilaiden erityiskoulun 8-13-vuotiaat oppilaat, joille opetettiin tunne- ja itsesäätelytaitoja Aggression portaat -opetusmateriaaliin (Cacciatore 2007) pohjautuvan intervention avulla. Kontrolliryhmän (N=26) oppilaat olivat interventioryhmän oppilaiden ikäisiä ja he opiskelivat Varsinais-Suomen alueen kouluissa pienluokissa myös käyttäytymiseen ja tunne-elämään liittyvien haasteidensa vuoksi. Kontrolliryhmän oppilaat eivät saaneet tutkimusjakson aikana interventio-ohjelman mukaista opetusta. Interventioryhmän oppilaat kävivät erityiskoulua, jossa kaikilla oppilailla oli sopeutumisongelmia ja kontrolliryhmän oppilaat opiskelivat yleisopetuksen koulujen yhteydessä olevilla sopeutumattomien oppilaiden pienluokilla. Tutkimusaineisto on kerätty vuosina 2010-2012. Tutkimusmetodeina olivat sekä oppilaille että opettajille laaditut Webropol-alustaiset kyselyt ja oppilaiden kirjoittamat väkivalta-aiheiset tekstit. Tutkimus- ja kontrolliryhmän oppilaille pidettiin ”Tunteiden hallinta ja käyttäytyminen”- kyselyn avulla alkumittaus syksyllä 2009 ja mittaus toistettiin keväällä 2010, 2011 ja 2012. Kyselyiden avulla selvitettiin, miten oppilaiden tunteiden kokeminen ja ilmaiseminen sekä tunteiden hallinta ja käyttäytymisen itsesäätely muuttuivat tutkimusjakson aikana. Kyselyssä kartoitettiin myös oppilaiden kokemuksia kiusaamisena ilmenevästä väkivallasta. Aineistolähtöisen sisällönanalyysin avulla selvitettiin oppilaiden kirjoitelmista heidän ajatuksiaan ja näkemyksiään väkivallasta ja ehdotuksia keinoista väkivallan vähentämiseksi. Keväällä 2012 interventioryhmän oppilaille ja opettajille laadittujen erillisten kyselyiden avulla selvitettiin sekä oppilaiden että opettajien arvioita ja kokemuksia oppilaiden tunne- ja itsesäätelytaitojen muutoksesta interventio-ohjelman avulla. Lisäksi oppilaat ja opettajat arvioivat pidettyjen tunnetaitotuntien hyödyllisyyttä oppilaille. Interventioryhmän opettajat arvioivat myös Aggression portaat -interventiomateriaalin käyttökelpoisuutta. Vuoden 2014 Perusopetuksen opetussuunnitelman perusteissa esitetyt velvoitteet opettaa kouluissa oppilaille tunne- ja vuorovaikutustaitoja edellyttävät tietoa konkreettisista käytänteistä ja tutkimusperustaisista interventio-ohjelmista. Tämän tutkimuksen tulokset osoittavat, että interventioryhmän muodostaneet sopeutumattomat oppilaat hyötyivät Aggression portaat -interventiosta. Heidän tunne- ja itsesäätelytaidoissaan tapahtui myönteistä kehitystä etenkin myönteisten tunnekokemusten lisääntymisen ja toisiin kohdistuneen fyysisen väkivallan vähenemisen osalta. Myös suhtautuminen väkivaltapelien ikärajoihin oli merkittävästi myönteisempää kuin kontrolliryhmän oppilailla, joilla kielteinen asenne lisääntyi selvästi tutkimusjakson aikana. Lisäksi interventioryhmän oppilailla oli keinoja itsensä rentouttamiseksi, päinvastoin kuin kontrolliryhmän oppilailla, joilla keinottomuuden kokemus jopa lisääntyi. Interventioryhmän oppilaat suhtautuivat hyvin kielteisesti toisen yllyttämiseen väkivaltaiseen tekoon ja kirjoittivat enemmän ajatuksiaan väkivallasta tuoden esille runsaasti ehdotuksia keinoista väkivallan vähentämiseksi. Myös oppilaat ja opettajat kokivat interventio-ohjelman oppilaiden kehityksen kannalta hyödylliseksi ja opettajat myös interventiomateriaalin käyttökelpoiseksi.

Statistical Inference for Computable General Equilibrium Models with Application to a Model of the Moroccan Economy

We study the problem of measuring the uncertainty of CGE (or RBC)-type model simulations associated with parameter uncertainty. We describe two approaches for building confidence sets on model endogenous variables. The first one uses a standard Wald-type statistic. The second approach assumes that a confidence set (sampling or Bayesian) is available for the free parameters, from which confidence sets are derived by a projection technique. The latter has two advantages: first, confidence set validity is not affected by model nonlinearities; second, we can easily build simultaneous confidence intervals for an unlimited number of variables. We study conditions under which these confidence sets take the form of intervals and show they can be implemented using standard methods for solving CGE models. We present an application to a CGE model of the Moroccan economy to study the effects of policy-induced increases of transfers from Moroccan expatriates.