Extensions of some classical methods in change point analysis

A common goal in modeling and data mining is to determine, based on sample data, whether or not a change of some sort has occurred in a quantity of interest. The study of statistical problems of this nature is typically referred to as change point analysis. Though change point analysis originated nearly 70 years ago, it is still an active area of research and much effort has been put forth to develop new methodology and discover new applications to address modern statistical questions. In this paper we survey some classical results in change point analysis and recent extensions to time series, multivariate, panel and functional data. We also present real data examples which illustrate the utility of the surveyed results.     

Effect of aggregation on estimators in AR(1) sequence

We consider the least squares estimator of the classical AR(1) process when the underlying variables are the aggregated sums of independent random coefficient AR(1) models. We establish the asymptotics of the corresponding statistics and show that this estimator, in general, is not a consistent estimator of the expected value of autoregressive parameter when the sample size, or number of aggregating terms, or both tend to infinity. We propose a modified bias-corrected form leading to a consistent estimator.     

A graphical editor and process visualization system for man-machine interfaces of dynamic systems

The process visualization system of a manmachine interface is presented. It allows human operator(s) to interact with a dynamic technical system, here a thermal power plant. Also, a graphical editor for designing dynamic pictures of the process visualization system is explained. Both new systems have a common architecture and are based on the computer graphics standard PHIGS-2D with extensions for handling non-graphical and graphical information. The hierarchical information structures are manipulated with lists and pointers in a dynamic visual database. The two menu-driven interfaces for designers and for operators are described with their multi-window display layouts. The software of both systems is highly portable to different hardware and to other application domains.     

The CRF1 receptor mediates the excitatory actions of corticotropin releasing factor (CRF) in the developing rat brain: in vivo evidence using a novel, selective, non-peptide CRF receptor antagonist

One of two groups of sheep was immunosuppressed with the glucocorticoid, dexamethasone, at the time of the first but not of the second of two booster vaccinations with tetanus toxoid given at an interval of 28 days. Treatment with dexamethasone decisively reduced the anti-tetanus antibody response to the first booster vaccination and affected both IgM and IgG1 antibody. However, antibody titres increased after the second booster vaccination in the treated sheep and were similar in size to those in the untreated sheep which rose in stepwise fashion after each booster vaccination. The differences in response imply that processes involved in displaying an anamnestic response and recalling previously established memory are sensitive to glucocorticoids. Accordingly, they can be separated from the glucocorticoid-resistant processes that lead to the expansion of immunological memory following multiple exposures to an antigen.     

Application of the Maillard,Strecker and modified Strecker (P–Mannich) reactions for the chemical modifications of wool

The application of the Maillard, Strecker and modified Strecker reactions in the chemical modification of wool are described. A practical method for improving reactive or acid dye pick–up under milder conditions of wool dyeing was the aim of the present work. This can be achieved by means of chemical bonding of selected carbohydrates with wool.     

Troglitazone increases system A amino acid transport in 3T3-L1 cells

System A is one of the most highly regulated transport systems for transport of neutral amino acids into mammalian cells. Stimulation of uptake of alpha-[3H]methylaminoisobutyric acid (MeAIB), a nonmetabolizable system A substrate, by a novel insulin-sensitizing agent, troglitazone, in 3T3-L1 adipocytes was investigated. Treating adipocytes with troglitazone alone resulted in a time- and dose-dependent increase in the uptake of MeAIB. The peak stimulation appeared about 24 h after troglitazone addition. Both troglitazone- and insulin-stimulated transport activities increased markedly after the induction of differentiation of preadipocytes into adipocytes, and declined to a steady state level in adipocytes. The stimulated MeAIB uptake exhibited substrate specificity typical of system A and was mediated by a single component as determined by Eadie-Hofstee plots. The stimulation by troglitazone and that by insulin were similarly sensitive to actinomycin D and cycloheximide, suggesting that both agents may induce de novo synthesis of the same type of system A transport. Apart from the insulin-independent effect, troglitazone also showed an insulin-dependent action characterized by enhanced sensitivity to insulin. The synergistic stimulation of MeAIB uptake by coadministration of insulin and troglitazone was most prominent at the early stages of adipocyte differentiation. Pretreating cells with troglitazone during the differentiation attenuated the sensitivity of insulin to inhibition by actinomycin D, suggesting that troglitazone may enhance the insulin action by stabilizing messenger RNA involved in system A function.     

Modeling the effect of oxygen on the amperometric response of immobilized organoselenium-based S-nitrosothiol sensors

Amperometric detection of S-nitrosothiols (RSNOs) at submicromolar levels in blood samples is of potential importance for monitoring endothelial function and other disease states that involve changes in physiological nitric oxide (NO) production. It is shown here that the elimination of dissolved oxygen from samples is critical when covalently attached diselenocystamine-based amperometric RSNO sensors are used for practical RSNO measurements. The newest generation of RSNO sensors utilizes an amperometric NO gas sensor with a thin organoselenium modified dialysis membrane mounted at the distal sensing tip. Sample RSNOs are catalytically reduced to NO within the dialysis membrane by the immobilized organoselenium species. In the presence of oxygen, the sensitivity of these sensors for measuring low levels of RSNOs (<μM) is greatly reduced. It is demonstrated that the main scavenger of the generated nitric oxide is not the dissolved oxygen but rather superoxide anion radical generated from the reaction of the reduced organoselenium species (the reactive species in the catalytic redox cycle) and dissolved oxygen. Computer simulations of the response of the RSNO sensor using rate constants and diffusion coefficients for the reactions involved, known from the literature or estimated from fitting to the observed amperometric response curves, as well as the specific geometric dimensions of the RSNO sensor, further support that nitric oxide and superoxide anion radical quickly react resulting in near zero sensor sensitivity toward RSNO concentrations in the submicromolar concentration range. Elimination of oxygen from samples helps improve sensor detection limits to ca. 10 nM levels of RSNOs.     

Editorial: Recent Advances in IoT as a Service (IoTaas 2017)

Mobile Networks and Applications -     

Iterative signal reconstruction of deliberately clipped SMT signals

Staggered MultiTone(SMT)is a modulation technique showing significantly reduced Adjacent Channel Leakage Ratio(ACLR)resulting in a more compact Power Spectrum Density(PSD)for the transmitted signal,than the well-known and already widely adopted Orthogonal Frequency Division Multiple Access(OFDMA)scheme.However,the unique spectral properties of an SMT signal could be degraded by a non-linear element(e.g.a Power Amplifier(PA))in the transmitter.Deliberate baseband clipping can be applied to the transmitted signal,reducing the notable high Peak-to-Average Power Ratio(PAPR).The objective of this paper is to give a brief introduction to the SMT scheme,with a special emphasis on deliberate clipping efects and their compensation.The paper introduces two receiver-oriented iterative methods aiming at the restoration of the baseband Bit Error Rate(BER)performance of a non-clipped signal.The methods are evaluated and compared based on numerical simulations.The paper concludes with the selection of a possible candidate for use in systems applying deliberately clipped SMT signals.