31 research outputs found
A Sequential Monte Carlo Approach for Online Stock Market Prediction Using Hidden Markov Models
A sequential Monte Carlo (SMC) algorithm prediction approach is developed based on joint probability distribution in hidden Markov Models (HMM). SMC methods, a general class of Monte Carlo methods, are typically used for sampling from sequences of distributions and simple examples of these algorithms are found extensively throughout the tracking and signal processing literature. Recent developments indicate that these techniques have much more general applicability and can be applied very effectively to statistical inference problems. Due to the problem involved in estimating the parameter of HMM, the HMM is represented in a state space model and the sequential Monte Carlo (SMC) method is used. Predictions are made using the SMC method in HMM and the corresponding on-line algorithm is developed. Daily stock price data from the banking sector of the Nigerian Stock Exchange (NSE) (price index between the years 1 January 2005 to 31 December 2008) are analyzed; experimental results reveal that the method proposed is effective
Comparing Two Examination Results using Means of Sample Means and Control Charts
Some examination candidates submit their scripts first, sometimes, for recognition as being brilliant, and some do for not knowing what to write. However, some equally submit last because they want to dot iâs and cross tâs. The objective of this research is to compare the results of both the earliest and latest submissions with the aim of finding out whether or not there is a significant difference between the two. The examination results of students of the Departments of Accounting, Business Administration and Industrial Relations and Personnel Management of the Faculty of Business Administration and the Department of Mathematics, Faculty of Science, University of Lagos were compared using means of sample means and two statistical quality control charts. The results showed that, generally, the early submissions seemed to be an indication of being more brilliant than the last submissions in the Faculty of Business Administration. In the Mathematics Department, however, the last to submit appeared to be more brilliant. Keywords:measures of brilliance, statistical quality control, two-sample test, ordered-data-control charts, time sequence of exam-script submission, competition assessmen
Subjective and objective measures
One of the greatest challenges in the study of emotions and emotional states is their measurement. The techniques used to measure emotions depend essentially on the authorsâ definition of the concept of emotion. Currently, two types of measures are used: subjective and objective. While subjective measures focus on assessing the conscious recognition of oneâs own emotions, objective measures allow researchers to quantify and assess the conscious and unconscious emotional processes. In this sense, when the objective is to evaluate the emotional experience from the subjective point of view of an individual in relation to a given event, then subjective measures such as self-report should be used. In addition to this, when the objective is to evaluate the emotional experience at the most unconscious level of processes such as the physiological response, objective measures should be used. There are no better or worse measures, only measures that allow access to the same phenomenon from different points of view. The chapterâs main objective is to make a survey of the main measures of evaluation of the emotions and emotional states more relevant in the current scientific panorama.info:eu-repo/semantics/acceptedVersio
Platelet-Rich Plasma Promotes the Proliferation of Human Muscle Derived Progenitor Cells and Maintains Their Stemness
Human muscle-derived progenitor cells (hMDPCs) offer great promise for muscle cell-based regenerative medicine; however, prolonged ex-vivo expansion using animal sera is necessary to acquire sufficient cells for transplantation. Due to the risks associated with the use of animal sera, the development of a strategy for the ex vivo expansion of hMDPCs is required. The purpose of this study was to investigate the efficacy of using platelet-rich plasma (PRP) for the ex-vivo expansion of hMDPCs. Pre-plated MDPCs, myoendothelial cells, and pericytes are three populations of hMDPCs that we isolated by the modified pre-plate technique and Fluorescence Activated Cell Sorting (FACS), respectively. Pooled allogeneic human PRP was obtained from a local blood bank, and the effect that thrombin-activated PRP-releasate supplemented media had on the ex-vivo expansion of the hMDPCs was tested against FBS supplemented media, both in vitro and in vivo. PRP significantly enhanced short and long-term cell proliferation, with or without FBS supplementation. Antibody-neutralization of PDGF significantly blocked the mitogenic/proliferative effects that PRP had on the hMDPCs. A more stable and sustained expression of markers associated with stemness, and a decreased expression of lineage specific markers was observed in the PRP-expanded cells when compared with the FBS-expanded cells. The in vitro osteogenic, chondrogenic, and myogenic differentiation capacities of the hMDPCs were not altered when expanded in media supplemented with PRP. All populations of hMDPCs that were expanded in PRP supplemented media retained their ability to regenerate myofibers in vivo. Our data demonstrated that PRP promoted the proliferation and maintained the multi-differentiation capacities of the hMDPCs during ex-vivo expansion by maintaining the cells in an undifferentiated state. Moreover, PDGF appears to be a key contributing factor to the beneficial effect that PRP has on the proliferation of hMDPCs. © 2013 Li et al
Social media marketing strategy: definition, conceptualization, taxonomy, validation, and future agenda
Although social media use is gaining increasing importance as a component of firmsâ portfolio of strategies, scant research has systematically consolidated and extended knowledge on social media marketing strategies (SMMSs). To fill this research gap, we first define SMMS, using social media and marketing strategy dimensions. This is followed by a conceptualization of the developmental process of SMMSs, which comprises four major components, namely drivers, inputs, throughputs, and outputs. Next, we propose a taxonomy that classifies SMMSs into four types according to their strategic maturity level: social commerce strategy, social content strategy, social monitoring strategy, and social CRM strategy. We subsequently validate this taxonomy of SMMSs using information derived from prior empirical studies, as well with data collected from in-depth interviews and a quantitive survey among social media marketing managers. Finally, we suggest fruitful directions for future research based on input received from scholars specializing in the field
Aridity trend and response to vegetation restoration in the loess hilly region of northern Shaanxi Province
Hybrid instrumental means of predictive analysis of the dynamics of natural and economic processes
The purpose of the presented research is the development and
adaptation of mathematical and instrumental methods of analysis and risk
management through the forecasting of both economic and natural time series
with memory based on the application of new mathematical methods of
investigation. The paper poses the problem of developing a constructive method
for predictive analysis of time series in the framework of the currently emerging
trend of using so-called âgraphical testsâ in the process of time seriesâ modeling
using nonlinear dynamics methods. The main purpose of using graphical tests is
to identify both stable and unstable quasiperiodic cycles (quasi-cycles), the
whole set of which includes a strange attractor (if one exists). New computer
technologies that made it possible to study complex phenomena and processes
âon a display screenâ were used as instrumentation for the implementation of
methods of non-linear dynamics. The proposed approach differs from classical
methods of forecasting by new implementation of accounting trends (the evolution
of centers and sizes of dimensional rectangles), and appears to be a new
tool for identifying cyclic components of the time series in question. As a result,
the person, that is making decision has more detailed information, which is
impossible to obtain by the methods of classical statistics.The work was supported by Russian Foundation for Basic Research (Grants â 17-06-00354 A).info:eu-repo/semantics/publishedVersio
The Effect of Cinnamon Extract on Spermatogenesis and
Genotypes of Iranian Zel sheep for Calpastatin (CAST) locus were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) methods and for Calpain (CAPN) locus by PCR-SSCP. Blood samples were collected from 200 purebred Zel sheep of Zel Breeding Station located in Golestan province in northeast of Iran. Extraction of genomic DNA was based on modified salting out method. The digestion of PCR products of CAST gene by MspI and NcoI restriction enzymes revealed two alleles M and N, with frequencies 85.5 and 14.5%, respectively. Frequencies were 75, 21 and 4% for MM, MN and NN genotypes, respectively. Alternatively, using PCR-SSCP method, four genotypes including AA, AB, BB and AC with frequencies of 71, 21, 4 and 4%, respectively, were observed in this population. Analyzing CAPN gene by the PCR-SSCP method, revealed two different conformational patterns (AA and AB) with frequencies of 69 and 31% for AA and AB, respectively. Average heterozygosity for both loci was low (0.28 and 0.25% for CAST using PCR-SSCP and PCR-RFLP, and 0.26% for CAPN). Yearling weights (YW) were analyzed by a statistical model comprising PCR-SSCP and as a result CAPN genotypes had significant effect (P<0.01) on YW. A Chi-square test confirmed Hardy-Weinberg (H-W) equilibrium for the CAST locus using PCR-SSCP method but not for PRC-RFLP method and CAPN locus. Totally, the investigated herd had little genetic diversity and different factors disturb H-W equilibrium and PCR-RFLP and PCR-SSCP might be used successfully in these studies