Safety first criterion and mean-shortfall criterion both explore cases of assets allocation with downside risk. In this paper, I compare safety first portfolio selection problem and mean-shortfall portfolio optimization problem, considering risk averse investors in practice. Safety first portfolio selection uses Value at Risk (VaR) as a risk measure, and mean-shortfall portfolio optimization uses expected shortfall as a risk measure, respectively. VaR is estimated by implementing extreme theory using a semi-parametric method. Expected shortfall is estimated by two nonparametric methods: a natural estimation and a kernel-weighted estimation. I use daily data on three international stock indices, ranging from January 1986 to February 2012, to provide empirical evidence in asset allocations and illustrate the performances of safety first and mean-shortfall with their risk measures. Also, the historical data has been divided in two ways. One is truncated at year 1998 and explored the performance during tech boom and financial crisis. the mean-shortfall portfolio optimization with the kernel-weighted method performed better than the safety first criterion, while the safety first criterion was better than the mean-shortfall portfolio optimization with the natural estimation method.

Tyrimo objektas – UAB ,, Suslavičius - Felix ‘‘ darbuotojai ir klientai. Darbo dalykas – UAB„Suslavičius - Felix ‘‘ darbuotojų ir klientų lojalumą lemiantys veiksniai. Tyrimo tikslas – parengti UAB ,, Suslavičius - Felix ‘‘ klientų lojalumo skatinimo priemones. Darbo tikslui įgyvendinti yra keliami tokie uždaviniai: 1) išanalizuoti lojalumo sampratas ir jų esmę; 2) nustatyti darbuotojų ir klientų lojalumą lemiančius veiksnius; 3) aptarti teorinius vartotojų lojalumo kūrimo proceso aspektus; 4) vadovaujantis teorine analize, parengti vartotojų lojalumo tyrimo metodiką; 5) atlikti įmonės darbuotojų ir klientų apklausą, įvertinant jų lojalumą; 6) atlikti UAB ,, Suslavičius - Felix ‘‘ darbuotojų ir klientų lojalumo lyginamąją analizę; 7) vadovaujantis teoriniu ir empiriniu tyrimų duomenimis, nustatyti UAB ,, Suslavičius - Felix ‘‘ darbuotojų ir klientų lojalumo skatinimo būdai; 8) parengti UAB „Suslavičius - Felix“ lojalumo skatinimo priemones. Tyrimo metodai: iškeltai problemai tirti ir teoriniams bei praktiniams rezultatams gauti naudoti šie tyrimo metodai: sisteminė analizė, loginė analizė, anketinė apklausa, lyginamoji analizė, grafinis vaizdavimas ir modeliavimas, rengiant UAB „Suslavičius - Felix“ lojalumo skatinimo priemones. / Research object - UAB ,, Suslavičius - Felix ‘‘ employees and clients. Research subject - UAB ,, Suslavičius - Felix ‘‘ factors influencing employees‘ and clients‘ loyalty Research aim (purpose) - UAB ,, Suslavičius - Felix ‘‘ motivating means of clients‘ loyalty. Objectives for to fulfil research purpose: 1. To analyse th conception and the point loyalty; 2. To establish factors influencing employees‘ and clients‘ loyalty; 3. To discuss theoretical aspects of consumers‘ loyalty creation process; 4. To prepare research methodic of loyalty of consumers following theoretical anlyse; 5. To carry out interrogatory of employees and clients estimating theirs‘ loyalty; 6. To carry out UAB ,, Suslavičius - Felix ‘‘employees and clients comparative analysis of loyalty; 7. To establish UAB ,, Suslavičius – Felix“ employees‘ and clients‘ ways of loyalty motivation, following theoretical and empirical research information; 8. To prepare UAB ,, Suslavičius – Felix“ motivating means of loyalty Research methods: To study a raised problem and to get theoretical and practical results it was used such research methods: methedical analysis, logical analysis, interrogatory of questionnaire, comparative analysis, graphics for UAB ,, Suslavičius – Felix“ motivating means of loyalty.

Natūralios odos fizikinėms–mechaninėms savybėms pagerinti taikomas mechaninio minkštinimo technologinis procesas. Naudojama keletas minkštinimo būdų: vibruojančiais puansonais, besisukančiais velenais srautinėse mašinose ir kt. Pagrindinė problema, su kuria susiduriama minkštinant odą – nėra prietais�� odos minkštumui nustatyti. Minkštumas vertinamas pagal odos standumą, o šis apskaičiuojamas išmatavus santykinį poilgį, esant tam tikro dydžio įtempiams. Norint nustatyti odos minkštumą, tiksliau, santykinį slankumą, su 113 minkštintos odos bandinių buvo atlikti du eksperimentai – tūrinis dviašis ir vienaašis tempimai. Grafiškai pavaizdavus santykinio slankumo, matuoto tūrinio dviašio tempimo principu, S0 priklausomybę nuo storio paaiškėjo, kad turimos odos bandinius reikia suskirstyti į dvi grupes. Tam buvo sprendžiamas režimo pasikeitimo uždavinys. Įžvelgus daugiau galimų režimo pasikeitimo taškų – režimo pasikeitimo uždavinio sprendimas pakartotas dar du kartus. Buvo apskaičiuoti gautų grupių grupuotų duomenų vidurkių ir dispersijų taškiniai ir intervaliniai įverčiai bei koreliacija. Visose nagrinėtose imtyse santykinio slankumo S0, matuoto tūrinio dviašio tempimo principu, duomenų dispersija yra kur kas mažesnė nei santykinio slankumo S1, matuoto vienaašio tempimo metodu, duomenų ir santykinio slankumo S0 grupuotos imties vidurkio bei dispersijos pasikliautinieji intervalai yra siauresni negu santykinio slankumo S1 grupuotos imties. Rezultatai rodo, kad vienaašio tempimo... [toliau žr. visą tekstą] / For the purpose of improvement of physical and mechanical qualities of natural leather, a mechanical softening process is applied. A number of particular softening technologies can be used, i.e. by means of a vibration punch, or using rotating shafts in flow machines, etc. The main issue encountered in the process of leather softening is unavailability of metering tools for determination of softening effect. Softness of leather is determined based on it’s rigidity, while the rigidity is calculated on the basis of measuring relation elongation at a certain tensioning. For the purpose of assessment of leather softness, or, to be more precise, relational fluidity, two experiments have been performed on 113 samples of softened leather, i.e. volume-based dual-axis tensioning and single-axis tensioning. Graphical rendering of the dependence of the relational fluidity, measured according to the principle of volume-based dual-axis tensioning, S0, on the thickness of leather has shown that the samples could be classified under two categories. For this purpose, a structural-change problem had to be resolved. As more possible structural change-points were identified, the structural-change problem was resolved two times more. The calculations have resulted in mean values and dispersion range values (point values and range values), as well as relevant correlations for the groups of the samples. All the sample range measured using volume-based dual-axis tensioning have shown a dispersion... [to full text]

We consider the motion of a Brownian particle trapped in an arbitrary bounded two or three-dimensional domain, whose boundary is reflecting except for a small absorbing window through which the particle can escape. We use the method of matched asymptotic expansions to calculate the mean first passage time, defined as the time taken for the Brownian particle to escape from the domain through the absorbing window. This is known as the narrow escape problem. Since the mean escape time diverges as the window shrinks, the calculation is a singular perturbation problem. We extend our results to include N absorbing windows of varying length in two dimensions and varying radius in three dimensions. We present findings in two dimensions for the unit disk, unit square and ellipse and in three dimensions for the unit sphere. The narrow escape problem has various applications in many fields including finance, biology, and statistical mechanics.

El CMC, tamaño y forma de micelas son características importantes en la determinación de sus principales propiedades y campos de aplicación. Esta tesis tiene dos partes, las transiciones de forma de las micelas que se trata con "Single chain Field Theory, /SCMFT)" y simulaciones de Monte Carlo. El SCMFT reveló todas las características esenciales de las transiciones de forma esférica a cilíndrica y esférica a disco de las micelas. MC muestra que las transiciones esfera a cilindro se produce a través de una región en que esferas y cilindros coexisten junto con otras formas intermedias.

Study object. The state managed forests of Middle Lithuanian plain landscape geographical region (Kedainiai, Birzai, Joniskis, Kaunas, Pakruojis and Panevezys forest enteprises) and Nemunas bottom-land plain geographical region (Tauragė, Jurbarkas, Sakiai, Kazlu Ruda and Marijampole forest enterprises). Study aim. To evaluate the forest yield capacity of nature and administrative units. Methodology. The forest yield capacity is evaluated by calculating the mean volume per hectare and by assessing the yield capacity using the methodology of S. G. Sinicin. Results. There was made a comparison of forest yield capacity between two geographical landscape regions (Middle Lithuanian plain and Nemunas bottom-land plain). It was assessed that the mean volume per hectare in Middle Lithuanian plain is 5,2% and the forest yield capacity (according to S.G. Sinicin) is 3,8 % higher than in Nemunas bottom-land plain geographical region. Further on it was made comparison between the mean volume and forest yield capacity per hectare in forest enterprises in these two geographical regions. It was assessed that the highest mean volumes have Kazlų Rūda, Šakiai and Marijampolė forest enterprises. The highest yield capacities (according to S.G. Sinicin) have Taurage, Jurbarkas and Šakiai forest enterprises. Key words: Middle Lithuanian plain landscape geographical region, Nemunas bottom-land plain landscape geographical region), forest yield capacity, mean volume per hectare. s 1 ha.

The ring of polynomials over a finite field has many arithmetic properties similar to those of the ring of rational integers. In this thesis, we apply the Hardy-Littlewood circle method to investigate the density of rational points on certain algebraic varieties in function fields. The aim is to establish asymptotic relations that are relatively robust to changes in the characteristic of the base finite field. More notably, in the case when the characteristic is "small", the results are sharper than their integer analogues.

Šiame darbe išnagrinėtas tiesinių sistemų parametrų įvertinimo metodas. Visas darbas susideda iš dviejų dalių: teorinės ir praktinės. Teorinėje dalyje aprašytas modelis, modelio kūrimas bei jo struktūra. Pateiktas Markovo įvertinimas arba įvertinimas apibendrintuoju mažiausiųjų kvadratų metodu, taip pat apibendrintojo modelio aprašymas, jo naudojimas. Praktinėje dalyje atlikti ir aprašyti eksperimentai. Modeliavimo eksperimentai atlikti naudojant programinį paketą MATLAB. Skaičiavimams atlikti buvo sukurtos ir panaudotos funkcijos matrica, period. Eksperimentų rezultatai pateikti lentelėse ir grafikuose. Padarytos išvados apie blokinio parametrų įvertinimo metodo efektyvumą. / In this work a block parameter estimation method for linear time-invariant systems is discussed. The whole work consists of two parts: theoretical and practical. The theoretical part is based on the description of the model, its creation and structure. Furthermore, Markov estimation or an estimation of the least squares generalized method and the description of the experiments and their description. The experiments of modeling have been performed using MATLAB program. In addition, the functions matrica, period were created and used to do the estimations. The results of the experiments are illustrated in charts and diagrams. Finally, the conclusions about the efficiency of the block parameter estimation method are done.

Engineers who develop fundamental models for chemical processes are often unable to estimate all of the model parameters due to problems with parameter identifiability and estimability. The literature concerning these two concepts is reviewed and techniques for assessing parameter identifiability and estimability in nonlinear dynamic models are summarized. Modellers often face estimability problems when the available data are limited or noisy. In this situation, modellers must decide whether to conduct new experiments, change the model structure, or to estimate only a subset of the parameters and leave others at fixed values. Estimating only a subset of important model parameters is a technique often used by modellers who face estimability problems and it may lead to better model predictions with lower mean squared error (MSE) than the full model with all parameters estimated. Different methods in the literature for parameter subset selection are discussed and compared. An orthogonalization algorithm combined with a recent MSE-based criterion has been used successfully to rank parameters from most to least estimable and to determine the parameter subset that should be estimated to obtain the best predictions. In this work, this strategy is applied to a batch reactor model using additional data and results are compared with computationally-expensive leave-one-out cross-validation. A new simultaneous ranking and selection technique based on this MSE criterion is also described. Unfortunately, results from these parameter selection techniques are sensitive to the initial parameter values and the uncertainty factors used to calculate sensitivity coefficients. A robustness test is proposed and applied to assess the sensitivity of the selected parameter subset to the initial parameter guesses. The selected parameter subsets are compared with those selected using another MSE-based method proposed by Chu et al. (2009). The computational efforts of these methods are compared and recommendations are provided to modellers. / Thesis (Master, Chemical Engineering) -- Queen's University, 2011-09-27 10:52:31.588

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