Dissertations / Theses on the topic 'Metoda ACEP'

The aim of this master thesis is the comparison of selected methods and parameters for roller bearings diagnostics. Selected statistical parameters are kurtosis, crest factor, and parameter K(t). The other selected methods are envelope analysis, cepstral analysis, and ACEP method. These methods are implemented in LabVIEW software and compared based on noise resistance, computation speed, and overall capability of identifying roller bearing faults.

Comparison of the performance of the ACER and POT methods for prediction of extreme values from heavy tailed distributions. To be able to apply the ACER method to heavy tailed data the ACER method was first modified to assume that the underlying extreme value distribution would be a Fréchet distribution, not a Gumbel distribution as assumed earlier. These two methods have then been tested with a wide range of synthetic and real world data sets to compare their preformance in estimation of these extreme values. I have found the ACER method seem to consistently perform better in the terms of accuracy compared to the asymptotic POT method.

Master's thesis deals with the security risks of current authentication methods. There are described methods which are based on user's knowledge and ownership of authentication object and biometric authentication method. The practical part of this Master's thesis deals with a specific design of authentication system based on protocol ACP, when the user proves his identity by smart card on provider assets, which is represented by ACP portal on the user's computer.

In this thesis we have explored the very high prices that sometimes occurs in the Nord Pool electricity market Elspot. By applying AR-GARCH time series models, extreme value theory, and ACER estimation techniques, we have sought to estimate the probabilities of threshold exceedances related to electricity prices. Of particular concern was the heavy-tailed Fréchet distribution, which was the asymptotic distribution assumed in the ACER estimation.We have found that with extreme value theory we are better equipped to deal with the very high quantiles in the time series we have analyzed. We have also described a method that can give an assessment of the probability of exceeding a selected level in the electricity price.

The aim of this dissertation was to investigate peak-to-average power ratio (PAPR) reduction techniques for filter bank multicarrier (FBMC) modulated systems. Research into current PAPR reduction techniques in FBMC and orthogonal frequency division multiplexing (OFDM) found that the active constellation extension (ACE) method has not been exploited for use in FBMC systems. This is, in part, due to the complexities involved in signal processing inherent of FBMC systems, as well as FBMC being a relatively new subject matter in the telecommunications field. The outcomes of the dissertation were four novel PAPR reduction techniques for FBMC systems. These techniques can be split up into two namely linear programming optimization ACE-based techniques and overlapping ACE techniques. The techniques compensate for the overlapping symbols in FBMC by utilizing a frame based approach. This characteristic makes them ideal candidates to be applied in burst transmission. Furthermore, because an ACE based technique is used, they do not require the transmission of side information. The PAPR performance of the techniques are shown to match, or in some cases improve, current PAPR techniques for FBMC. The analysis of the proposed approaches also address some complexity issues with current FBMC implementations. The out-of-band (OOB) interference of the techniques under clipping scenarios is investigated. It is shown that the OOB interference can be minimized whilst still maintaining good PAPR performance. Additional results are also provided by means of a study of the PAPR reduction techniques proposed as applied to a high power amplifier based model. The corresponding power amplifier efficiency as well as bit-error rate (BER) degradation are investigated and compared to other standard techniques for PAPR reduction in FBMC systems. It was found that the proposed techniques can achieve a higher amplifier efficiency than existing techniques at a marginal trade-off in BER degradation. This BER degradation is lower than existing techniques due to the marginal increase in average transmit power. As illustrated by exhaustive simulations, the single scaling and overlapping smart gradient-project ACE-based techniques proposed, are ideal candidates for practical implementation in systems employing the low complexity polyphase implementation of FBMC modulators. The methods are shown to offer significant PAPR reduction and increase the feasibility of FBMC as a replacement modulation system for OFDM.
Die doel van hierdie verhandeling is om top-tot-gemiddelde drywingsverhouding (PAPR) verminderingstegnieke vir filterbank veelvuldige draer (FBMC) -gemoduleerde stelsels te ondersoek. Huidige PAPR verminderingstegnieke in FBMC en ortogonale frekwensie verdeling multipleksering (OFDM) is ondersoek en daar is bevind dat die aktiewe konstellasie uitbreidingsmetode (ACE) nog nie vantevore ontgin is in FBMC stelsels nie. Dit is gedeeltelik as gevolg van die inherente kompleksiteit van seinverwerking in FBMC stelsels en ook omdat FBMC n relatief nuwe onderwerp in die veld van telekommunikasie is. Die resultate van hierdie verhandeling is vier unieke PAPR verminderingstegnieke vir FBMC stelsels. Hierdie tegnieke kan opgedeel word in lineêre programeringsgeoptimiseerde tegnieke en oorvleuelende ACE tegnieke. Om vir die oorvleueling van simbole in FBMC te vergoed, word n raamgebaseerde benadering gebruik. Hierdie kenmerk maak hierdie tegnieke ideaal vir vlaaguitsending. Omdat n ACE-gebaseerde tegniek gebruik word, is transmissie van kant inligting onnodig. Die PAPR werkverrigting van dié tegnieke is op standaard met, en in sommige gevalle n verbetering op huidige PAPR tegnieke vir FBMC. Die ontleding van die voorgestelde benaderings spreek ook die kompleksiteitkwessies met die implementering van huidige tegnieke aan. Die buite band (OOB) steuring van die tegnieke onder geknipte scenarios word ondersoek. Daar word getoon dat die OOB steuring verminder kan word terwyl goeie PAPR verrigting gehandhaaf word. Addisionele studieresultate word ook voorsien deur n studie van die voorgestelde PAPR reduksietegnieke toegepas op n hoë drywing versterker (HPA)model. Die ooreenstemmende drywingsversterker doeltreffendheid asook die degradering van die bit fout waarde (BER) is ondersoek en vergelyk met ander tegnieke vir PAPR vermindering in FBMC stelsels. Daar is bevind dat die voorgestelde tegnieke n hoër drywing versterker doeltreffendheid kan bereik as bestaande tegnieke afgespeel ten koste van n marginale BER degradasie. Hierdie degradasie is laer as bestaande tegnieke as gevolg van die marginale toename in gemiddelde uitsendingskrag. Uitvoerige simulasies toon dat die voorgestelde enkel skalering en oorvleuelende slim gradiënt projek ACE gebaseerde tegnieke die ideale kandidate is vir praktiese toepassing in stelsels wat gebruik maak van die lae kompleksiteit veelfase toepassing van FBMC modulators. Dié metodes bring n beduidende PAPR vermindering te weeg en maak FBMC meer haalbaar as n vervanging modulasie stelsel vir OFDM.
Dissertation (MEng)--University of Pretoria, 2015.
tm2016
Electrical, Electronic and Computer Engineering
MEng
Unrestricted

Abstract Surface water and sediment samples collected from Jukskei River in South Africa, were subjected to different extraction techniques, liquid–liquid (LLE), solidphase extraction (SPE), activated carbon extraction (ACE) and soxhlet extraction (SE) for sediment. The samples were extracted with dichloromethane, cleaned in a silica gel column and the extracts quantified using a Varian 3800 GC-ECD. The percentage recovery test for 2,40DDT, DDE and DDD and 4,40DDT, DDE and DDD in water ranged from 80%–96% and 76%–95% (LLE); 56%–76% and 56%–70% (SPE) and 75%–84% (ACE), respectively; while that recoveries for sediment samples varied from 65%– 95% for 2,40DDT, DDE and DDD and 80%–91% for 4,40DDT, DDE and DDD. The high recoveries exhibited by ACE compared very well with LLE and SE. This was not the case with SPE which exhibited the lowest value of recoveries for both 2,4 and 4,40DDD, DDE and DDT standard samples. The mean concentrations of DDT and metabolites ranged from nd-1.10 lg/L, nd-0.80 lg/L, nd- 1.21 lg/L and 1.92 lg/L for LLE, SPE, ACE and SE, respectively. The total DDT (2,40 and 4,40-DDT) in water and sediment samples ranged from 1.20–3.25 lg/L and 1.82–5.24 lg/L, respectively. The low concentrations of the DDT metabolites obtained in the present study may suggest a recent contamination of the river by DDT.

In this Master's thesis we have used data from eight different locations in Norway to estimate the distributions of extreme water levels. The locations used are Oslo, Heimsjø, Honningsvåg, Narvik, Harstad, Tregde, Andenes and Viker, and four different methods have been used for the estimation. We use two established and widely used methods, the Annual Maxima Method (AMM) and the Peaks-over-Threshold (POT) method. The AMM uses the observed annual maxima from each location, while the POT method uses the exceedances of some high threshold in relation to the data. In addition, we also use two approaches that are less known and less used, the Revised Joint Probability Method (RJPM) and the Average Conditional Exceedance Rate (ACER) method. In the former, a distribution for extreme surges is found and used together with information from numerical tide predictions. We also take into account the interaction between tides and surges where applicable. The ACER method uses only the series of measured sea levels, but tries to account for dependence by a cascade of conditioning probabilities. We find that for return periods up to 20 years the return levels are usually very similar for all methods except RJPM, which seems to underestimate these values. The data intensive methods of POT, RJPM and ACER seem to agree for the 200 year levels, while particularly the Gumbel method seems to overshoot the levels in comparison to the other methods.

The present work is aimed at investigating the mechanisms of nanowire growth from aqueous solutions through a physical and chemical modeling. Based on this modeling, deriving an optimized process control is intended. The work considers two methods of nanowire growth. The first is the dielectrophoretic nanowire assembly from neutral molecules or metal clusters. Secondly, in the directed electrochemical nanowire assembly metal-containing ions are reduced in an AC electric field in the vicinity of the nanowire tip and afterwards deposited at the nanowire surface. To describe the transport and growth processes, continuum models are employed. Furthermore, it has been necessary to consider electro-kinetic fluid flows to match the experimental observations. The occurring partial differential equations are solved numerically by means of finite element method (FEM). The effect of the process parameters on the nanowire growth are analyzed by comparing experimental results to a parameter study. The evaluation has yielded that an AC electro-osmotic fluid flow has a major influence on the dielectrophoretic nanowire assembly regarding the growth velocity and morphology. In the case of directed electrochemical nanowire assembly, the nanowire morphology can be controlled by the applied AC signal shape. Based on the nanowire growth model, an optimized AC signal has been designed, whose parametrization allows to adjust to the chemical precursor and the desired nanowire diameter
Ziel der vorliegenden Arbeit ist es, mittels physikalischer und chemischer Modelle die Mechanismen des Nanodrahtwachstums aus wässrigen Lösungen zu erforschen und daraus eine optimierte Prozesskontrolle abzuleiten. Dabei werden zwei Verfahren des Nanodrahtwachstums näher betrachtet: Dies sind die dielektrophoretische Assemblierung von neutralen Molekülen oder Metallclustern sowie die gerichtete elektrochemische Nanodrahtabscheidung (engl. directed electrochemical nanowire assembly), bei der metallhaltige Ionen im elektrischen Wechselfeld an der Nanodrahtspitze zunächst reduziert und anschließend als Metallatome abgeschieden werden. Zur Beschreibung der Transport- und Wachstumsprozesse werden Kontinuumsmodelle eingesetzt. Darüber hinaus hat es sich als notwendig erwiesen, elektrokinetische Fluidströmungen zu berücksichtigen, um die experimentellen Beobachtungen zu reproduzieren. Die auftretenden partiellen Differenzialgleichungen werden mittels der Finiten Elemente Methode (FEM) numerisch gelöst. Die Auswirkungen der Prozessparameter auf das Nanodrahtwachstum werden durch den Vergleich von experimentellen Ergebnissen mit Parameterstudien analysiert. Die Auswertung hat ergeben, dass für das dielektrophoretische Wachstum ein durch Wechselfeldelektroosmose (engl. AC electro-osmosis) angetriebener Fluidstrom die Drahtwachstumsgeschwindigkeit und -morphologie maßgeblich beeinflusst. Im Falle der gerichteten elektrochemischen Nanodrahtabscheidung lässt sich die Drahtmorphologie über das angelegte elektrische Wechselsignal steuern. Unter Verwendung des Wachstumsmodells ist ein optimiertes Signal generiert worden, dessen Parametrisierung eine gezielte Anpassung auf den chemischen Ausgangsstoff und den gewünschten Drahtdurchmesser erlaubt

Les nouvelles technologies développées ces dernières années dans le domaine de la génétique ont permis de générer des bases de données de très grande dimension, en particulier de Single Nucleotide Polymorphisms (SNPs), ces bases étant souvent caractérisées par un nombre de variables largement supérieur au nombre d'individus. L'objectif de ce travail a été de développer des méthodes statistiques adaptées à ces jeux de données de grande dimension et permettant de sélectionner les variables les plus pertinentes au regard du problème biologique considéré. Dans la première partie de ce travail, un état de l'art présente différentes méthodes de sélection de variables non supervisées et supervisées pour 2 blocs de variables et plus. Dans la deuxième partie, deux nouvelles méthodes de sélection de variables non supervisées de type "sparse" sont proposées : la Group Sparse Principal Component Analysis (GSPCA) et l'Analyse des Correspondances Multiples sparse (ACM sparse). Vues comme des problèmes de régression avec une pénalisation group LASSO elles conduisent à la sélection de blocs de variables quantitatives et qualitatives, respectivement. La troisième partie est consacrée aux interactions entre SNPs et dans ce cadre, une méthode spécifique de détection d'interactions, la régression logique, est présentée. Enfin, la quatrième partie présente une application de ces méthodes sur un jeu de données réelles de SNPs afin d'étudier l'influence possible du polymorphisme génétique sur l'expression du vieillissement cutané au niveau du visage chez des femmes adultes. Les méthodes développées ont donné des résultats prometteurs répondant aux attentes des biologistes, et qui offrent de nouvelles perspectives de recherches intéressantes

博士
國立成功大學
電機工程學系碩博士班
95
The two major research topics for algebraic code excited linear predictive (ACELP) of this dissertation are efficient translation and coding methods. First, we proposed the architecture of transcoding between global system for mobile communications (GSM) half rate and G.729 Speech Coders across Mobile and IP Networks. Second, the fast stochastic codebook search algorithms for reduction of the algebraic code excited linear predictive (ACELP) are proposed. The speech coding translation scheme by transferring coding parameters between GSM half rate and G.729 coders is proposed over wireless and network. Compared to the conventional decode-then-encode (DTE) scheme, the proposed parameter conversions provide speech interoperability with reducing computational complexity and coding delay. Simulation results show that the proposed methods can reduce about 30% computational load achieve almost imperceptible degradation in performance. To reduce the computational complexity of Algebraic Code-Excited Linear Prediction (ACELP) coders, we propose an efficient codebook search mechanism based on a simplified correlation matrix of the vocal impulse response. Furthermore, proposed Joint scheme by combining the simplified correlation matrix method and a pulse position prediction scheme, it not only decreases arithmetic complexity in pre-computing autocorrelation matrix but also reduce the number of pulse position combinations. The simulation and experimental results show that the proposed method provides an effective reduction in the computational load of the ACELP codebook search procedure with no discernible degradation of the speech quality.

碩士
國立臺灣海洋大學
河海工程學系
107
The steel structure has high toughness, high strength, good shock resistance, less green energy pollution, and prefabrication and construction speed.Therefore, steel structure engineering is a trend trend and the number of construction projects is increasing, depending on the construction process of the steel structure.A single operation is discussed and analyzed.Under the influence of the environment and weather, etc……., the construction process has been operated under the "traditional method" for a long time. In addition to the problem of the subsequent construction interface caused by the derivative precision control, more serious accidents of falling or dumping are caused.In order to achieve safety and quality improvement, in recent years, the domestic introduction of "AceUp steel-free ropework method" to respond to the results, the results are outstanding.According to the workplace example, after discussing and comparing the construction method with the "traditional construction method", it is verified that "AceUp steel-free ropework method" has deep (1) safety improvement, (2) quality improvement, (3) noise prevention, and (4) shortening.Construction period, (5) saving manpower and reducing the cost of quality benefits.Its applicability can be advanced research and development and application to complex roof molding structures and inclined steel column installations for the construction of the industry to achieve the purpose of project management and enhance the competitiveness of steel structures.

有各式各樣的參數與非參數期貨定價模型被廣泛應用於金融領域。其中一些模型的組合能顯著提升期貨定價的準確性。更具體的說，可以先通過參數模型擬合數據，再使用非參數模型學習並修正誤差估價誤差。本論文作為范和Mancini(2009) 結果的延伸，將市場交易的歐式期權價格作為輸入數據，運用「有參數模型指導的非參數定價方法」對障礙期權進行估價。「自動誤差修正估價法」運用非參數方法對由參數估價法產生的誤差進行修正，使得障礙期權的非參數定價模型可以被視為一系列的歐式期權定價的組合。在整個障礙期權的估價過程中，本論文同時提供了一種分數階快速傅裡葉變換的應用，可通過由非參數方法獲得的標的資產對數的存活函數計算標的資產對數最大值分佈的特徵函數。
There are a variety of parametric and nonparametric option pricing models commonly used in Finance. A combination of them can enhance the pricing performance significantly. Specifically, one proposes to fit the data with a parametric method and then correct the pricing errors empirically with a nonparametric learning approach. This thesis extends Fan and Mancini's (2009) model-guided nonparametric method to barrier option pricing using market traded European option data. Adopting automatic correction of errors (ACE) method to estimate the risk neutral conditional survivor function, by which the pricing error of the initial parametric estimates is captured nonparametrically, enables the nonparametric pricing procedure to value a barrier option as a sum of sequence of European options. As a byproduct from the valuation process, this thesis also provides a modified fractional fast Fourier transform technique compute the characteristic function of the running maximum log-price of the underlying asset nonparametrically through the calibrated survivor functions.
Detailed summary in vernacular field only.
Chi, Chengzhan.
Thesis (M.Phil.)--Chinese University of Hong Kong, 2013.
Includes bibliographical references (leaves 38-39).
Abstracts also in Chinese.
Chapter 1 --- Introduction --- p.1
Chapter 2 --- Nonparametric Local Regression Modelling --- p.4
Chapter 2.1 --- Function Estimation by Local Constant --- p.4
Chapter 2.2 --- Function Estimation by Local Linear Regression --- p.5
Chapter 3 --- Nonparametric ACE European Option Pricing --- p.7
Chapter 3.1 --- European Option Prices and Risk Neutral Survivor Functions --- p.7
Chapter 3.2 --- Estimation of Risk Neutral Survivor Functions --- p.10
Chapter 3.2.1 --- Risk Neutral Survivor Functions and Traded Options --- p.10
Chapter 3.2.2 --- Survivor Function Estimation with Nonparametric ACE Method --- p.11
Chapter 3.3 --- Representation of European Option Prices at Log-asset Level and Numerical Example --- p.15
Chapter 4 --- Nonparametric ACE Barrier Option Pricing Framework --- p.20
Chapter 4.1 --- Continuous-time Barrier Option --- p.20
Chapter 4.2 --- Discrete Approximation and Backward Induction --- p.21
Chapter 4.3 --- Decomposed Problems --- p.25
Chapter 5 --- Nonparametric Estimation of Cumulative Distribution Function of M{U+2C7C}(R{U+209C}) --- p.28
Chapter 5.1 --- Survivor Functions and Maxima Probabilities --- p.28
Chapter 5.2 --- Characteristic Functions of Maxima --- p.30
Chapter 5.2.1 --- Algorithm --- p.30
Chapter 5.2.2 --- Preparation --- p.31
Chapter 5.2.3 --- Fast Fourier Transform (FFT) --- p.31
Chapter 5.2.4 --- Fractional Fast Fourier Transform (FRFT) --- p.33
Chapter 5.2.5 --- Derivation of ΦR{U+209C} --- p.34
Chapter 5.3 --- Numerical Experiments --- p.35
Chapter 6 --- Conclusion --- p.37
Bibliography --- p.38

碩士
亞洲大學
心理學系碩士班
101
This study investigated the effectiveness of a psychoeducation methods on college students‟ attitudes toward PTSD. A quasi-experimental research design was adopted while 121 students from Syiah Kuala University, Banda Aceh, Indonesia were invited to participate in four groups. Participants in three experimental groups received different psychoeducational methods of receiving handouts, listening to lectures, and attending interactive discussion while those in control group received nothing. All participants were administered with Attitudes toward PTSD scale before and after the psychoeducation methods within 2 weeks. Research results showed that participants of experimental groups scored significantly higher on post-test (p>.000) comparing to those of the control group. Three psychoeducation methods increased college students‟ positive attitudes toward PTSD in this study. Result of analysis indicated that lecturing was the most effective psychoeducational method to attitudinal changes. Findings from the study for a short-duration, in this case, a two-week period of psychoeducation methods, can effectively increase college students' attitudes toward PTSD, reduce negative attitudes towards PTSD. Implications for future research and psychoeducation for PTSD were discussed.

碩士
東吳大學
企業管理學系
94
The global PC industry is now in the heated mature stage. Related brand name companies in the PC industry are looking for different competitive advantage in the critical survival time. Looking through the Top 10 PC brand names globally in this low marginal profit environment, such as Dell, HP, Lenovo, Acer, Fujitsu, Toshiba, NEC, Apply, Gateway, and Sony, they are working continuously on vertical integration, horizontal work delegation, or merge and acquisition of the competitors in the attempt to expand the market. Via cooperative research and development, manufacturing subcontracting, innovative channel marketing, global resource integration, and as well as other strategies in order to create cost competitiveness and in turn largely expand the economic scale. However, different kinds of development strategies do not have absolute right or wrong, and in fact it depends on if the strategy can match the corporate business model, core competitiveness and value chain to create the overall entity value. In order for a PC brand name company, suffering in the fast changing and overwhelming market competitions, to lead the competitors, the company must use creative thinking to create winning managing model while elevate the company’s competitive advantage to create on-going entity value. However, the crucial key to success is the global marketing strategy (based on American or other markets), product strategy (targeted or diversified), channel strategy (selling direct or through distribution channels, internet or traditional), and along with the strategy of merging and acquisition (aggressive or conservative). In the past archive, it is rare to see the global Top 10 PC brand name company uses EVA (Economy Value Added) as the primary exploration for corporate managing performance. This research is aimed to use EVA as the analysis index for management performance index, in the attempt to explore the Top 10 PC brand names management performance index in the past five years. To form a fair basis for comparing different companies, this research adopts Standard EVA to eliminate the differences between the companies. Additionally, this research is going to explore the effectiveness of management index and efficiency of capital usage, in order to form the reference point for evaluating performance index and future improvement. Through regional sales market analysis, this research will include conceptual analysis on the effectiveness of management performance index for PC brand names, by discussing the main sales market in the USA and non-USA regional groups, highs and lows in the sales ratio of PC products, selling direct or through sales distribution, and whether or not conducting merging and acquisition. This research adopts EVA and consideration for debt and cost of equity shares. It will evaluate the managing performance of the Top 10 PC companies by adjusting the added equity and avoiding traditional accounting evaluation. In addition, EVA and other frequently used comparison index, such as Return on Assets and Return on Owner’s Equity, are used to understand the main difference. Besides from the case study of EVA, interview with the high ranking manager in Acer, which currently is ranked 4th among Taiwan’s PC brand names, is conducted to discuss about managing strategy and provide insights. The followings are concluded from the case study: 1. Discussion on the EVA trend in the past five years: Acer’s combined EVA for the past five years indicated a negative value, but it is changing to favorable situation and turning from negative to positive in 2004. HP has the best total EVA performance, and maintains positive value every year. Even though HP faced a down slop in 2003. Coming second is Dell, which also has positive value every year, and its EVA is on the rise in 2003. These two companies have created the steady and highest economic added values. Apple and Gateway both have negative value on the total EVA in the past five years. Apple, on the other hand, is turning from negative to positive in 2004 and its innovative product strategy proves that it does indeed bring the turning point. Gateway’s EVA is fluctuating at a large scale, and it demonstrates instability in the management. After the merge and acquisition in 2004, eMachine is showing profitability and its EVA is showing as positive once again. Besides these companies, the Japanese PC companies Sony, Fujitsu and NEC are showing positive value of EVA, but the fluctuation shows instability in the management performance. 2. Discussion on the “Standard EVA” average in the past five years: To form a fair basis for every company, the ranking after eliminating scale difference and deriving the “Standard EVA” shows similar ranking in the previous EVA. The first three are Dell, HP and Sony, while the last three are Acer, Apple, and Gateway. Acer’s average “Standard EVA” is poorer than other companies. However, after subcontracting to the newly created company Wistron Technology in 2002, the core competitiveness for brand management is therefore enhanced and its “Standard EVA” is on the rise. In 2004, it showed a positive “Standard EVA” and the ranking boosted up to the 6th. This demonstrates that the management performance index is turning favorable and the economic added values are raised. In terms of the “Standard EVA” for other companies, Dell is leading the way ahead of the competitors. It surpasses HP, because Dell’s capital investment is smaller than the HP. After eliminating the scale difference, the managing performance is turning favorable. 3. Analysis on company’s key managing strategy: For the companies targeting on the USA market, the five-year “Standard EVA” is higher than the average of the sales group outside of the USA. This indicates that the better management performance and sales market are in the more mature market the USA. In terms of product types, PC has the ratio of more than 50%, and this applies to Acer, Dell and Gateway, whose five-year average EVA is poorer, but the five-year average of “Standard EVA” is better than the group with 50% and below. It is on the growing trend for the past two years; it shows that companies with higher PC ratio are having lower capital investment. Therefore, after eliminating the scale difference, the companies focused on PC branding have more favorable management performance. Dell, the internet direct selling company, has higher performance than the distribution agent direct selling Acer and other traditional channel selling companies. This shows the no boundary Business to Consumer direct selling and custom made BTO have desirable performance index. Among the Top 10 PC brand name companies, merging and acquisition in the past five years has not yet reflected on the overall management performance index. Moreover, many companies undergo merging during unfavorable management performance situation. This has resulted the management performance is difficult to realize in the early stage and would require more justified analysis after continuous observation on the company’s future situation. 4. Comparing Acer’s EVA, “Standard EVA”, ROA, ROE and frequently used performance index: Even though Acer’s EVA is gradually turning favorable, its five-year average still reflects negative value and the worst situation happened in 2001. However, the trend for its Return on Assets and Return on Equity shows contrary situation. It has had positive rate of return in the consecutive five years, and 2002 showed the highest record. This is mainly because from 2000 and 2002, the profits are mainly from the non-core sales. Its core sales showed losses, and had resulted negative on NOPAT. Even though NOPAT, ROA and ROE were all positive in 2003, the performance was not well due to over investing on the capital. As a result, the 2003 EVA was negative and was minimizing. The 2004 EVA was turning from negative to positive; however, the profitability of its core sales needs to improve and the resource usage efficiency must be fortified.

\textbf{Molecular Determinants of Drug-Target Residence Times of Bacterial Enoyl-ACP Reductases.} Whereas optimization processes of early drug discovery campaigns are often affinity-driven, the drug-target residence time $t_R$ should also be considered due to an often strong correlation with \textit{in vivo} efficacy of compounds. However, rational optimization of $t_R$ is not straightforward and generally hampered by the lack of structural information about the transition states of ligand association and dissociation. The enoyl-ACP reductase FabI of the fatty acid synthesis (FAS) type II is an important drug-target in antibiotic research. InhA is the FabI enzyme of \textit{Mycobacterium tuberculosis}, which is known to be inhibited by various compound classes. Slow-onset inhibition of InhA is assumed to be associated with the ordering of the most flexible protein region, the substrate binding loop (SBL). Diphenylethers are one class of InhA inhibitors that can promote such SBL ordering, resulting in long drug-target residence times. Although these inhibitors are energetically and kinetically well characterized, it is still unclear how the structural features of a ligand affect $t_R$. Using classical molecular dynamics (MD) simulations, recurring conformational families of InhA protein-ligand complexes were detected and structural determinants of drug-target residence time of diphenyl\-ethers with different kinetic profiles were described. This information was used to deduce guidelines for efficacy improvement of InhA inhibitors, including 5'-substitution on the diphenylether B-ring. The validity of this suggestion was then analyzed by means of MD simulations. Moreover, Steered MD (SMD) simulations were employed to analyze ligand dissociation of diphenylethers from the FabI enzyme of \textit{Staphylococcus aureus}. This approach resulted in a very accurate and quantitative linear regression model of the experimental $ln(t_R)$ of these inhibitors as a function of the calculated maximum free energy change of induced ligand extraction. This model can be used to predict the residence times of new potential inhibitors from crystal structures or valid docking poses. Since correct structural characterization of the intermediate enzyme-inhibitor state (EI) and the final state (EI*) of two-step slow-onset inhibition is crucial for rational residence time optimization, the current view of the EI and EI* states of InhA was revisited by means of crystal structure analysis, MD and SMD simulations. Overall, the analyses affirmed that the EI* state is a conformation resembling the 2X23 crystal structure (with slow-onset inhibitor \textbf{PT70}), whereas a twist of residues Ile202 and Val203 with a further opened helix $\alpha 6$ corresponds to the EI state. Furthermore, MD simulations emphasized the influence of close contacts to symmetry mates in the SBL region on SBL stability, underlined by the observation that an MD simulation of \textbf{PT155} chain A with chain B' of a symmetry mate in close proximity of the SBL region showed significantly more stable loops, than a simulation of the tetrameric assembly. Closing Part I, SMD simulations were employed which allow the delimitation of slow-onset InhA inhibitors from rapid reversible ligands. \textbf{Prediction of \textit{Mycobacterium tuberculosis} Cell Wall Permeability.} The cell wall of \textit{M. tuberculosis} hampers antimycobacterial drug design due to its unique composition, providing intrinsic antibiotic resistance against lipophilic and hydrophilic compounds. To assess the druggability space of this pathogen, a large-scale data mining endeavor was conducted, based on multivariate statistical analysis of differences in the physico-chemical composition of a normally distributed drug-like chemical space and a database of antimycobacterial--and thus very likely permeable--compounds. The approach resulted in the logistic regression model MycPermCheck, which is able to predict the permeability probability of small organic molecules based on their physico-chemical properties. Evaluation of MycPermCheck suggests a high predictive power. The model was implemented as a freely accessible online service and as a local stand-alone command-line version. Methodologies and findings from both parts of this thesis were combined to conduct a virtual screening for antimycobacterial substances. MycPermCheck was employed to screen the chemical permeability space of \textit{M. tuberculosis} from the entire ZINC12 drug-like database. After subsequent filtering steps regarding ADMET properties, InhA was chosen as an exemplary target. Docking to InhA led to a principal hit compound, which was further optimized. The quality of the interaction of selected derivatives with InhA was subsequently evaluated using MD and SMD simulations in terms of protein and ligand stability, as well as maximum free energy change of induced ligand egress. The results of the presented computational experiments suggest that compounds with an indole-3-acethydrazide scaffold might constitute a novel class of InhA inhibitors, worthwhile of further investigation
\textbf{Molekulare Determinanten von Wirkstoff-Angriffsziel Verweilzeiten bakterieller Enoyl-ACP Reduktasen.} In frühen Phasen der Wirkstoffentwicklung sind Optimierungsprozesse häufig affini\-täts\-geleitet. Darüber hinaus sollte zusätzlich die Wirkstoff-Angriffsziel Verweilzeit $t_R$ berücksichtigt werden, da diese oft eine starke Korrelation zur \textit{in vivo} Wirksamkeit der Substanzen aufweist. Rationale Optimierung von $t_R$ ist jedoch auf Grund eines Mangels an struktureller Information über den Übergangszustand der Ligandbindung und Dissoziierung nicht einfach umsetzbar. Die Enoyl-ACP Reduktase FabI der Fettsäurebio\-synthese (FAS) Typ II ist ein wichtiger Angriffspunkt in der Antibiotikaforschung. InhA ist das FabI Enzym des Organismus \textit{Mycobacterium tuberculosis} und kann durch Substanzen diverser Klassen gehemmt werden. Es wird vermutet, dass Hemmung von InhA durch langsam-bindende (``slow-onset'') Inhibitoren mit der Ordnung der flexibelsten Region des Enzyms assoziiert ist, dem Substratbindungsloop (SBL). Diphenylether sind eine InhA Inhibitorenklasse, die eine solche SBL Ordnung fördern und dadurch lange Verweilzeiten im Angriffsziel aufweisen. Obwohl diese Inhibitoren energetisch und kinetisch gut charakterisiert sind, ist noch immer unklar, wie die strukturellen Eigenschaften eines Liganden $t_R$ beeinflussen. Durch die Verwendung klassischer Molekulardynamik (MD) Simulationen wurden wiederkehrende Konformationsfamilien von InhA Protein-Ligand Komplexen entdeckt und strukturelle Determinanten der Wirkstoff-Angriffsziel Verweilzeit von Diphenylethern mit verschiedenen kinetischen Profilen beschrieben. Anhand dieser Ergebnisse wurden Richtlinien zur Wirksamkeitsoptimierung von InhA Inhibitoren abgeleitet, einschließlich einer 5'-Substitution am Diphenylether B-Ring. Die Validität dieses Vorschlags wurde mittels MD Simulationen nachfolgend analysiert. Darüber hinaus wurden ``Steered MD'' (SMD) Simulationen als MD Technik für umfangreicheres Sampling verwendet um die Liganddissoziation von Diphenylethern aus dem FabI Enzym von \textit{Staphylococcus aureus} zu untersuchen. Dieser Ansatz resultierte in einem sehr akkuraten, quantitativen linearen Regressionsmodell der experimentellen Verweilzeit $ln(t_R)$ dieser Inhibitoren als Funktion der berechneten maximalen freien Energieänderung induzierter Ligandextraktion. Dieses Modell kann genutzt werden um die Verweilzeiten neuer potentieller Inhibitoren aus Kristallstrukturen oder validen Dockingposen vorherzusagen. Die korrekte strukturelle Charakterisierung des intermediären und des finalen Zustandes (EI und EI*-Zustand) eines Enzym-Inhibitor Komplexes bei einem zweistufigen Inhibitionsmechanismus durch langsam-bindende Hemmstoffe ist essentiell für rationale Verweilzeitoptimierung. Daher wurde die gegenwärtige Ansicht des EI und EI*-Zustandes von InhA mittels Kristallstrukturanalyse, MD und SMD Simulationen erneut aufgegriffen. Insgesamt bestätigten die Analysen, dass der EI*-Zustand einer Konformation ähnlich der 2X23 Kristallstruktur (mit langsam-bindenden Inhibitor \textbf{PT70}) gleicht, während eine Drehung der Reste Ile202 und Val203 mit einer weiter geöffneten Helix $\alpha 6$ dem EI-Zustand entspricht. Des Weiteren zeigten MD Simulationen den Einfluss naher Kristallkontakte zu Symmetrie-Nachbarn in der SBL Region auf die SBL Stabilität. Dies wird durch die Beobachtung hervorgehoben, dass die Ketten A und B' eines InhA-\textbf{PT155}-Komplexes und des angrenzenden Symmetrie-Nachbars, welche in engem Kontakt in der SBL Region stehen, signifikant stabilere SBLs aufweisen, als die Ketten A und B in einer Simulation des Tetramers. Zum Abschluss von Teil I wurden SMD Simulationen angewandt, auf deren Basis es möglich war, langsam-bindende InhA Inhibitoren von schnell-reversiblen (``rapid reversible'') Liganden zu unterscheiden. \textbf{Vorhersage von \textit{Mycobacterium tuberculosis} Zellwand Permeabilität.} Die Zellwand von \textit{M.~tuberculosis} erschwert die antimycobakterielle Wirkstofffindung auf Grund ihrer einzigartigen Zusammensetzung und bietet eine intrinsische Antibiotikaresistenz gegenüber lipophilen und hydrophilen Substanzen. Um den chemischen Raum wirkstoffähnlicher Moleküle gegen diesen Erreger (``Druggability Space'') einzugrenzen, wurde eine groß angelegte Dataminingstudie durchgeführt, welche auf multivariater statistischer Analyse der Unterschiede der physikochemischen Zusammensetzung eines normalverteilten wirkstoffähnlichen chemischen Raumes und einer Datenbank von antimycobakteriellen -- und somit höchstwahrscheinlich permeablen -- Substanzen beruht. Dieser Ansatz resultierte in dem logistischen Regressionsmodell MycPermCheck, welches in der Lage ist die Permeabilitätswahrscheinlichkeit kleiner organischer Moleküle anhand ihrer physikochemischen Eigenschaften vorherzusagen. Die Evaluation von MycPermCheck deutet auf eine große Vorhersagekraft hin. Das Modell wurde als frei zugänglicher online Service und als lokale Kommandozeilenversion implementiert. Methodiken und Ergebnisse aus beiden Teilen dieser Dissertation wurden kombiniert um ein virtuelles Screening nach antimycobakteriellen Substanzen durchzuführen. Myc\-PermCheck wurde verwendet um den chemischen Permeabilitätsraum von \textit{M.~tuberculosis} anhand der gesamten ZINC12 Datenbank wirkstoffähnlicher Moleküle abzuschätzen. Nach weiteren Filterschritten mit Bezug auf ADMET Eigenschaften, wurde InhA als exemplarisches Angriffsziel ausgewählt. Docking nach InhA führte schließlich zu einer Treffersubstanz, welche in darauffolgenden Schritten weiter optimiert wurde. Die Interaktionsqualität ausgewählter Derivate mit InhA wurde daraufhin mittels MD und SMD Simulationen in Bezug auf Protein und Ligand Stabilität, sowie auch der maximalen freien Energieänderung induzierter Ligandextraktion, untersucht. Die Ergebnisse der vorgestellten computerbasierten Experimente legen nahe, dass Substanzen mit einem Indol-3-Acethydrazid Gerüst eine neuartige Klasse von InhA Inhibitoren darstellen könnten. Weiterführende Untersuchungen könnten sich somit als lohnenswert erweisen

The present work is aimed at investigating the mechanisms of nanowire growth from aqueous solutions through a physical and chemical modeling. Based on this modeling, deriving an optimized process control is intended. The work considers two methods of nanowire growth. The first is the dielectrophoretic nanowire assembly from neutral molecules or metal clusters. Secondly, in the directed electrochemical nanowire assembly metal-containing ions are reduced in an AC electric field in the vicinity of the nanowire tip and afterwards deposited at the nanowire surface. To describe the transport and growth processes, continuum models are employed. Furthermore, it has been necessary to consider electro-kinetic fluid flows to match the experimental observations. The occurring partial differential equations are solved numerically by means of finite element method (FEM). The effect of the process parameters on the nanowire growth are analyzed by comparing experimental results to a parameter study. The evaluation has yielded that an AC electro-osmotic fluid flow has a major influence on the dielectrophoretic nanowire assembly regarding the growth velocity and morphology. In the case of directed electrochemical nanowire assembly, the nanowire morphology can be controlled by the applied AC signal shape. Based on the nanowire growth model, an optimized AC signal has been designed, whose parametrization allows to adjust to the chemical precursor and the desired nanowire diameter.
Ziel der vorliegenden Arbeit ist es, mittels physikalischer und chemischer Modelle die Mechanismen des Nanodrahtwachstums aus wässrigen Lösungen zu erforschen und daraus eine optimierte Prozesskontrolle abzuleiten. Dabei werden zwei Verfahren des Nanodrahtwachstums näher betrachtet: Dies sind die dielektrophoretische Assemblierung von neutralen Molekülen oder Metallclustern sowie die gerichtete elektrochemische Nanodrahtabscheidung (engl. directed electrochemical nanowire assembly), bei der metallhaltige Ionen im elektrischen Wechselfeld an der Nanodrahtspitze zunächst reduziert und anschließend als Metallatome abgeschieden werden. Zur Beschreibung der Transport- und Wachstumsprozesse werden Kontinuumsmodelle eingesetzt. Darüber hinaus hat es sich als notwendig erwiesen, elektrokinetische Fluidströmungen zu berücksichtigen, um die experimentellen Beobachtungen zu reproduzieren. Die auftretenden partiellen Differenzialgleichungen werden mittels der Finiten Elemente Methode (FEM) numerisch gelöst. Die Auswirkungen der Prozessparameter auf das Nanodrahtwachstum werden durch den Vergleich von experimentellen Ergebnissen mit Parameterstudien analysiert. Die Auswertung hat ergeben, dass für das dielektrophoretische Wachstum ein durch Wechselfeldelektroosmose (engl. AC electro-osmosis) angetriebener Fluidstrom die Drahtwachstumsgeschwindigkeit und -morphologie maßgeblich beeinflusst. Im Falle der gerichteten elektrochemischen Nanodrahtabscheidung lässt sich die Drahtmorphologie über das angelegte elektrische Wechselsignal steuern. Unter Verwendung des Wachstumsmodells ist ein optimiertes Signal generiert worden, dessen Parametrisierung eine gezielte Anpassung auf den chemischen Ausgangsstoff und den gewünschten Drahtdurchmesser erlaubt.