Academic literature on the topic 'Tobim'

Texte remanié de: Promotionsschrift--Fachbereich Evangelische Theologie--Marburg--Philipps-Universität, 1992.<br>Contient en annexe la trad. allemande du Livre de Tobie. Bibliogr. p. [201]-225. Index.

I produktionen på Tobii Technologys strävan att nå sina interna mål med leveranssäkerhet och minimalt med bundet kapital i lager, har det visat sig nödvändigt att undersöka företagets produktionsprognoser. Syftet med ex-jobbet är därför att utreda hur väl produktionsprognoserna stämmer överens med den faktiska efterfrågan samt att fastställa hur Tobii bör arbeta i produktionsprognosprocessen för att säkerställa att komponentlagret baseras på bästa möjliga underlag. Som första steg genomfördes en nulägesanalys för att skapa en uppfattning av den nuvarande situationen och dess svårigheter. En kombination av en kvantitativ och kvalitativ metod bedömdes vara av störst intresse för att säkerställa att alla synpunkter beaktades i undersökningen, vilken baserades på personliga intervjuer med samtliga berörda chefer involverade i prognosarbetet. En litteraturstudie genomfördes inom de områden som hade relevanta bidrag till problemformuleringen; främst prognostisering och processhantering, och en iterering av metodstudier och förslag till lösning genomfördes. Undersökningsprocessen var en iterativ process där den erhållna teoretiska och företagsspecifika informationen reducerades med fokus på problemformuleringen och med hjälp av avgränsningarna. Dragna slutsatser genererade återkoppling som gjorde ytterligare datainsamling nödvändig. Undersökningen visar att den faktiska efterfrågan inom affärsområdet Analysis Solutions kan anses överensstämma väl med de prognostiserade behoven. Varken komponentbrist eller för stora lager borde således existera inom affärsområdet. Så är dock inte fallet. Såväl brist på komponenter som ett delvis överdimensionerat lager föreligger stundtals. Grunden till detta problem måste därför ligga på annat håll i produktionen. Granskningen av Assistive Technologys prognoser kan inte med säkerhet svara på huruvida eventuella komponentbrister kan härstamma från för låga prognoser. Detta beror på den historiskt sett undermåliga dokumenthanteringen. Det verkar dock som att prognoserna har varit för låga på vissa produkter. Det är därför viktigt att en fortsatt bevakning sker av dessa prognoser så att prognosens roll i problematiken kan uteslutas. För ett antal produkter kan det med stor säkerhet konstateras att prognoserna genomgående har legat för högt. Det har även gått att koppla lagerinköpen till dessa prognoser vilket betyder att ökade lagerkostnader inom detta affärsområde delvis kan härledas tillbaka till prognosfelen. Affärsområdet Future Markets har troligtvis något höga prognoser i jämförelse med efterfrågan. Komponentbrist borde därmed inte existera i produktionen vilket dock är fallet. Detta kan antingen bero på att samma komponenter till stor del ingår i produkter ur Assistive Technologys sortiment; om deras prognoser har legat för lågt kan de ha absorberat detta behov, eller så kan det bero på andra felkällor inom produktion. Det handlar dock inte om någon större kapitalbindning eftersom de höga prognoserna inte ger något större utslag då de avser så pass små kvantiteter. En prognosprocess med ansvarig processägare har utformats och införts. Ett flödesschema som tydliggör de ingående aktiviteterna, ansvarsområdena samt tidsramen, har upprättats. I denna process har informationsflödet och terminologin säkrats. Bland annat har ett nytt produktionsprognosdokument samt ett återkopplingsdokument, där mer detaljerad information kan återfinnas, skapats. Samtliga dokument återfinns i det dokumenthanteringssystem som har införts.<br>In the efforts of Tobii Technology’s production to achieve its internal goal of on time delivery and minimal net assets in stocks, it has proved necessary to examine the production prognosis. The purpose of the thesis is therefore to examine how well the production prognoses match the actual demand and to define the Tobii should work in the production prognosis process to ensure that the component layer is based on the best information available. As a first step a situation analysis was performed to create a perception of the current situation and its difficulties. A combination of quantitative and qualitative method was judged to be of greatest interest to ensure that all aspects were considered in the survey. The survey was based on personal interviews with all the managers involved in prognosis. A literature review was conducted in the areas that contained relevant contribution to the problem statement, mainly forecasting and process management, and iterations of method study and proposed solutions was implemented. The investigation process was an iterative process in which the obtained theoretical and company-specific information was reduced by focusing on the problem using the boundaries. Drawn conclusions generated feedback that made additional data collection necessary. The result shows that the actual demand within the Business Area Analysis Solutions can be considered to agree well with the projected needs. Neither component shortage nor a large stock should therefore exist in the business area. This is not the case. Lack of components as well as over-stocking sometimes exists. The basis of this problem must therefore lie elsewhere in production. The audit of the Assistive Technology forecasting cannot reliably answer whether any component failures may stem from the low projections as a result of substandard records management. However, it appears that the forecasts have been too low on some products. It is therefore important to continue monitoring the effectiveness of these forecasts so that the forecast's role in the problem can be ruled out. For a number of products it can with great certainty be claimed that the projections have consistently been too high. It also agreed that the stock purchases are linked to these projections, which means increased storage costs in this sector can be partly traced back to the forecast errors. The business area Futures Markets probably has a little high forecast in comparison with the demand. Component deficiency should therefore not exist in production but this is sometimes the case. This may be due to the fact that the same components are largely contained in the products from the Assistive Technology product range. If their forecasts have been too low they may have absorbed this need, but it may also be due to other sources of error in production. Since the quantities in this business unit are relatively small these prognosis errors will not lead to any significant amounts of capital being tied up. A prognosis process with a responsible process owner has been designed and introduced. A flow chart has been prepared which clarifies the operations, responsibilities and the time frame. In this process, the flow of information and terminology has been secured. Among other things, a new production prognosis document and a discussion paper, where additional information can be found, was created. All documents are contained in the document management system which has been introduced.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1999.<br>Includes bibliographical references (p. [42]-[43]).<br>The Tobin Bridge was a significant transportation improvement which gave automobile travelers from Chelsea and the North Shore unprecedented high-speed access to Boston. Through the first 50 years of the 20th century, Chelsea wanted a high-speed bridge but could not afford to build one, and also could not convince the state of Massachusetts or the city of Boston to finance a new bridge. In 1946, the state legislature created the Mystic River Bridge Authority, a public authority which built a high-level bridge by issuing bonds whose repayment was based upon expected toll revenues. The construction process was briefly delayed by protests from community members and their elected representatives, who objected to the residential displacements the bridge caused. The Mystic River Bridge opened in February, 1950, and was renamed the Maurice J. Tobin Bridge in 1967.<br>by Kelly Davenport.<br>M.C.P.

O crescimento econômico brasileiro se manteve a baixos níveis nas duas últimas décadas quando comparado ao seu desempenho histórico e ao crescimento internacional. Um dos principais fatores responsáveis por esta situação é o pouco significativo nível de Q de Tobin da economia. Nesse sentido, este trabalho tem por objetivo verificar se os fundamentos macroeconômicos explicam o comportamento do Q de Tobin, que estimula as decisões de Q de Tobin das empresas. Empiricamente, será utilizado um modelo de seleção automática: Autometrics.<br>Brazilian economic growth has been low for the last two decades, when compared to its historical performance and international growth. One of the main factors responsible for this situation is the small level of investment in the economy. This work aims to verify whether macroeconomic fundamentals can explain the behavior of Tobin\'s Q, which is supposed to be an indicator of investment decisions of the firms. Empirically, it will be employed an automatic selection model: Autometrics.

Master of Science<br>Department of Statistics<br>Weixing Song<br>In the classical Tobit regression model, the regression error term is often assumed to have a zero mean normal distribution with unknown variance, and the regression function is assumed to be linear. If the normality assumption is violated, then the commonly used maximum likelihood estimate becomes inconsistent. Moreover, the likelihood function will be very complicated if the regression function is nonlinear even the error density is normal, which makes the maximum likelihood estimation procedure hard to implement. In the full nonparametric setup when both the regression function and the distribution of the error term [epsilon] are unknown, some nonparametric estimators for the regression function has been proposed. Although the assumption of knowing the distribution is strict, it is a widely adopted assumption in Tobit regression literature, and is also confirmed by many empirical studies conducted in the econometric research. In fact, a majority of the relevant research assumes that [epsilon] possesses a normal distribution with mean 0 and unknown standard deviation. In this report, we will try to develop a semi-parametric estimation procedure for the regression function by assuming that the error term follows a distribution from a class of 0-mean symmetric location and scale family. A minimum distance estimation procedure for estimating the parameters in the regression function when it has a specified parametric form is also constructed. Compare with the existing semiparametric and nonparametric methods in the literature, our method would be more efficient in that more information, in particular the knowledge of the distribution of [epsilon], is used. Moreover, the computation is relative inexpensive. Given lots of application does assume that [epsilon] has normal or other known distribution, the current work no doubt provides some more practical tools for statistical inference in Tobit regression model.

<p> The first chapter of my thesis explores monetary policy in a New Keynesian model with Markov-switching risk aversion. The second considers the implications for the macroeconomic and financial properties of an RBC model of the presence of habit formation. The third examines the result of adding the ``Tobin constraint" that shares equal the capital stock to a benchmark RBC mdoel. The underlying theme of these endeavors is rendering macroeconomic models more realistic via the introduction of time-varying preferences, non-linear modelling, and financial frictions.</p>

In this work, we develop a non-standard linear regression analysis by considering that the dependent variable is censored and also that some of the explanatory variables are measured with additive errors. In addition, our censored measurement error regression model is speci ed by assuming heavy-tailed distributions for the underlying probabilistic process. Speci cally, our analysis focuses on assuming a multivariate Student-t joint distribution for the error terms and the unobserved true covariates. In this sense, the proposed model will be robust enough to protect our inferences of atypical or in uential observations. For the model estimation, we consider the maximum likelihood methodology, in which we include the estimation of the asymptotic variance of the maximum likelihood estimators and we also develop an EM type algorithm to obtain the estimates, and also the Bayesian paradigm, in which we use a data augmentation approach and develop a MCMC algorithm to sample from the posterior distributions. The proposed methodology is exible enough to be adapted for heavy-tailed distributions coming from the class of scale mixture of the normal distribution. The performance of the newly developed methodology is evaluated throughout a Monte Carlo study as well as a case sudy analysis.<br>Neste trabalho é desenvolvida uma análise de regressão linear considerando que a variável dependente é censurada e também que algumas das variáveis explicativas são medidas com erros aditivos. Esse modelo de regressão censurado com erros de medidas é especificado assumindo distribuições com cauda pesada para o processo probabilístico. Especificamente, assume-se uma distribuição t-Student multivariada para modelar o comportamento conjunto dos erros e das verdadeiras covariáveis não observadas. Nesse sentido, o modelo será robusto o suficiente para proteger as inferências de observações atípicas e influentes. Para a estimação do modelo considera-se a metodologia de máxima verossimilhança, em que inclui-se a estimação da variância assintótica dos estimadores de máxima verossimilhança e também desenvolve-se um algoritmo do tipo EM para obter as estimativas, e também o paradigma bayesiano, onde considera-se o procedimento de aumento de dados e desenvolve-se um algoritmo MCMC para amostrar das distribuições a posteriori. A metodologia proposta flexível o bastante para ser adaptada para distribuições com caudas pesadas vindas da classe de misturas de escala da distribuição normal. A performance da nova metodologia desenvolvida é avaliada através de um estudo Monte Carlo e também de uma análise de um estudo de caso.

Master of Science<br>Department of Statistics<br>Weixing Song<br>A nonparametric lack-of-fit test is proposed to check the adequacy of the presumed parametric form for the regression function in Tobit regression models by applying Zheng's device with weighted residuals. It is shown that testing the null hypothesis for the standard Tobit regression models is equivalent to test a new null hypothesis of the classic regression models. An optimal weight function is identified to maximize the local power of the test. The test statistic proposed is shown to be asymptotically normal under null hypothesis, consistent against some fixed alternatives, and has nontrivial power for some local nonparametric power for some local nonparametric alternatives. The finite sample performance of the proposed test is assessed by Monte-Carlo simulations. An empirical study is conducted based on the data of University of Michigan Panel Study of Income Dynamics for the year 1975.