Comparative Study Of Various Approaches Research Articles

Casimir free energy for massive scalars: A comparative study of various approaches

We compute the Casimir thermodynamic quantities for a massive real scalar field between two parallel plates with the Dirichlet boundary conditions, using three different general approaches and present explicit solutions for each. The Casimir thermodynamic quantities include the Casimir Helmholtz free energy, pressure, energy, and entropy. The three general approaches that we use are based on the fundamental definition of Casimir thermodynamic quantities, the analytic continuation method, and the zero temperature subtraction method. Within the analytic continuation approach, we use two distinct methods which are based on the utilization of the zeta function and the Schlömilch summation formula. We include the renormalized versions of the latter two approaches as well, whereas the first approach does not require one. Within each general approach, we obtain the same results in a few different ways to ascertain the selected cancellations of infinities have been done correctly. We show that, as expected, the results based on the zeta function and the Schlömilch summation formula are equivalent. We then do a comparative study of the three different general approaches and their results and show that they are in principle not equivalent to each other, and they yield equivalent results only in the massless case. In particular, we show that the Casimir energy calculated only by the first approach has all three properties of going to zero as the temperature, mass of the field or the distance between the plates increases. Moreover, we show that in this approach the Casimir entropy reaches a positive constant in the high temperature limit, which can explain the linear term in the Casimir free energy. We use the results obtained by the fundamental approach as our reference for the correct results.

A Comparative Study of Various Approaches for Producing Probabilistic Forecasts of Upper-Level Aviation Turbulence

Abstract The skill of operational deterministic turbulence forecasts is impacted by the uncertainties in both weather forecasts from the underlying numerical weather prediction (NWP) models and diagnoses of turbulence from the NWP model output. This study compares various probabilistic turbulence forecasting approaches to quantify these uncertainties and provides recommendations on the most suitable approach for operational implementation. The approaches considered are all based on ensembles of NWP forecasts and/or turbulence diagnostics, and include a multi-diagnostic ensemble (MDE), a time-lagged NWP ensemble (TLE), a forecast-model NWP ensemble (FME), and combined time-lagged MDE (TMDE) and forecast-model MDE (FMDE). Both case studies and statistical analyses are provided. The case studies show that the MDE approach that represents the uncertainty in turbulence diagnostics provides a larger ensemble spread than the TLE and FME approaches that represent the uncertainty in NWP forecasts. The larger spreads of MDE, TMDE, and FMDE allow for higher probabilities of detection for low percentage thresholds at the cost of increased false alarms. The small spreads of TLE and FME result in either hits with higher confidence or missed events, highly dependent on the performance of the underlying NWP model. Statistical evaluations reveal that increasing the number of diagnostics in MDE is a cost-effective and powerful method for describing the uncertainty of turbulence forecasts, considering trade-offs between accuracy and computational cost associated with using NWP ensembles. Combining either time-lagged or forecast-model NWP ensembles with MDE can further improve prediction skill and could be considered if sufficient computational resources are available.

Casimir free energy for massive fermions: a comparative study of various approaches

We compute the Casimir thermodynamic quantities for a massive fermion field between two parallel plates with the MIT boundary conditions, using three different general approaches and present explicit solutions for each. The Casimir thermodynamic quantities include the Casimir Helmholtz free energy, pressure, energy and entropy. The three general approaches that we use are based on the fundamental definition of Casimir thermodynamic quantities, the analytic continuation method represented by the zeta function method, and the zero temperature subtraction method. We include the renormalized versions of the latter two approaches as well, whereas the first approach does not require one. Within each general approach, we obtain the same results in a few different ways to ascertain the selected cancellations of infinities have been done correctly. We then do a comparative study of the three different general approaches and their results, and show that they are in principle not equivalent to each other and they yield, in general, different results. In particular, we show that the Casimir thermodynamic quantities calculated only by the first approach have all three properties of going to zero as the temperature, the mass of the field, or the distance between the plates increases.

Comparative study of various approaches, applications and classifiers for sentiment analysis

In today's day and age, there are billions of volumes of textual content being generated everywhere. In-apps messages like WhatsApp, Telegram, social media sites like Facebook, Instagram, news publishing sites, google searches and many other sources. All these sources are constantly generating huge volumes of text data every second. And because of these huge volumes of text data NLP becomes a vital resource in understanding the textual content. In this paper, the main focus is on the popular NLP task of Sentiment analysis. Sentiment analysis is contextual mining of text which identifies and extracts subjective information in textual data. sentiment analysis proves to be an incredible asset for users to extract essential information and assists organizations with understanding the social sentiment of their brand, product or service while monitoring online conversations. This paper investigates the different approaches and classification models used in the task of sentiment analysis.

Off-shell vs on-shell modelling of top quarks in photon associated production

We present a comparative study of various approaches for modelling of the {e}^{+}{v}_e{mu}^{-}{overline{v}}_{mu }boverline{b}gamma final state in toverline{t}gamma production at the LHC. Working at the NLO in QCD we compare the fully realistic description of the top quark decay chain with the one provided by the narrow-width-approximation. The former approach comprises all double, single and non-resonant diagrams, interferences, and off-shell effects of the top quarks. The latter incorporates only double resonant contributions and restricts the unstable top quarks to on-shell states. We confirm that for the integrated cross sections the finite top quark width effects are small and of the order of mathcal{O}left({Gamma}_t/{m}_tright) . We show, however, that they are strongly enhanced for more exclusive observables. In addition, we investigate fractions of events where the photon is radiated either in the production or in the decay stage. We find that large fraction of isolated photons comes from radiative decays of top quarks. Based on our findings, selection criteria might be developed to reduce such contributions, that constitute a background for the measurement of the anomalous couplings in the toverline{t}upgamma vertex.

Lord Denning’s influence on contract formation in Singapore—an overdue demise?

ABSTRACTIn a series of inconsistent decisions by the Singapore courts on contract formation in continuing negotiations cases, Lord Denning’s broad approach—which does away with the traditional offer and acceptance analysis—appears to have been simultaneously adopted and rejected. This article suggests that the continued uncertainty in Singapore regarding the scope of application of the traditional approach and Lord Denning’s approach arises from a conflation of both as being substantially similar. This article further argues that both approaches are conceptually and practically distinct. A better way forward for Singapore law in the area of contract formation in continuing negotiations cases, having regard to developments in English law and a comparative study of various approaches taken in international instruments and jurisdictions around the world, is to affirm the traditional approach as the default rule, subject to displacement in exceptional situations.

Approaches to laser speckle reduction for uniform illumination of the field of view of a microscope during biophysical studies

A comparative study of various approaches to speckle reduction showed that the use of a liquid crystal-based speckle reducer did not allow complete elimination of speckles. The use of mechanical devices for blurring of the speckle pattern in the field of view turned out to be more efficient in the case of quantitative luminescent microscopy. Virtually complete reduction of speckles was observed when a device that combines a ring-shaped fiber-optic light source and a vibration unit that shifts the butt-ends of optical fibers relative to the laser diode during measurement was used. This speckle-reduction approach was successfully used in microarray analysis.

Comparative Study of Various Approaches for Human Identification and Gait Recognition

Biometrics is totally based on contactable human body parts. But there is a need of such a biometric technique which is noncontactable, non-invasive and which should not be get hide by using some aspect. Gait is the pattern of movement and comes under the biometrics and it is the unique characteristic of individuals. The approach of this paper is to introduces the comparative study of various approaches of recognize the human by their gate. This paper represents the various gait recognition and human recognition techniques. Keywords: gait cycle, pattern recognition, biometrics

A review of various approaches to optimize the solar air heater

A comparative study of various approaches to optimise and increase the performance of solar air heater is carried out in the present work. Various types of artificial roughness geometries in the absorber plate of solar air heater duct and their characteristics have been investigated for the heat transfer improvement or enhance the performance by many researchers. However, exergy data are more practical and realistic in comparison with the respective energy values that have been found in this communication.

In the Shadow of Great Powers: A Comparative Study of Various Approaches to Regionalism in Central Asia

Alongside the rapid development of globalization, the post-Cold War era has witnessed the expansion of various forms of regional cooperation in many areas of the world. Regionalism, therefore—both in reference to the construction of a regional identity (“soft regionalism”) and the building of regional cooperative institutions (“hard regionalism”) —has become a salient ongoing process worldwide, involving the participation of both states and non-state actors as a response to globalization. Different from the “old regionalism” that arose immediately after World War II, which underscored the economic and security dimensions of regional integration and the dominant role of external power or even hegemony in it, the “new regionalism” that is increasingly widespread nowadays emphasizes spontaneous regional cooperation in a variety of areas, including politics, economy, security, culture, etc. For Central Asia (a region consisting of Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Turkmenistan), however, the “new regionalism” wave has not yet arrived. Instead, a pattern of great power-sponsored regionalism has dominated the development of structures of regional cooperation. Although the dissolution of the USSR and the following independence of the five Central Asian states once generated opportunities to form self-sustaining regional cooperation frameworks based on common interests that could lead to a functioning regionalism, the disagreements among the states caused by water resource disputes, border issues, and other conflicts of interest impeded them from making substantial moves. In addition, since the newly independent states in Central Asia are quite concerned with their hard-won sovereignty and are still hampered by their relatively poor economic performance, the political will and national capabilities to promote usually binding regional cooperation projects are inevitably inadequate. A good instance of such challenges is the failure of the Central Asian Cooperation Organization (CACO), a spontaneously initiated regional project consisting of all the five Central Asian states.

Comparative study of various approaches to stochastic elastic wave propagation

Three approaches to the problem of 1-D wave propagation in media with random elastic and mass properties are studied: (i) method of integral spectral decomposition, (ii) the Fokker-Plank-Kolmogorov equation, and (iii) the Dyson integral equation. Merits and shortcomings of each approach are discussed. It is shown that the approaches cover actually all possible problems of the harmonic wave propagation in heterogeneous or stochastic media, hence, by means of a preliminary analysis of a particular problem and bearing in mind the strong and weak sides of each approach, one can choose an appropriate solution strategy.

A comparative study of various approaches for ctod toughness evaluation

A comparative assessment of various methods proposed for CTOD toughness evaluation has been made on two structural steels. CTOD values are obtained from experimental CMOD data by direct extrapolation as given by Wells' method, BS5762 etc. On the other hand the toughness values based on R- curves (multiple specimen method) are also obtained using various proposed blunting lines. An attempt is made in the present work to find a more realistic blunting line from stretch zone width measurement. Two specific geometries, namely compact tension (CT) and three point bending are considered, besides studying the thickness effects on CTOD. The conventional methods (BS5762 etc.) are found to yield more conservative values, while the R- curve approach considered with a blunting line provides a more realistic estimation of toughness. No clear and systematic dependency of thickness could be observed. However, the CT geometry results in higher CTOD toughness than bend geometry apparently because of a lower constraint factor.

Correlations between topological features and physicochemical properties of molecules

The article reviews in brief, thede novo group additivity approach and, at length, the different topological approaches to obtain predictive and internally consistent correlations between various properties and structural features of molecules. The stress has mainly been on the molecular connectivity method. A new rational scheme for nomenclature of connectivity indices of different orders and types is introduced. The concept of the perturbation connectivity parameter developed by us recently has been applied to obtain correlations for molar refraction, boiling point, molar volume, heat of atomisation, heat of combustion, heat of vaporisation, magnetic susceptibility and critical constants of alkanes, alcohols and alkylbenzenes. A comparative study of various approaches reveals that the present perturbation topological approach has an edge over other similar methods.