Raw Series Data Research Articles

An astroclimatological study of candidate sites to host an imaging atmospheric Cherenkov telescope in Romania

We come out in this paper with an astroclimatological study of meteorological data on relative humidity, dew point temperature, air temperature, wind speed, barometric air pressure, and sky cloudiness recorded at four Romanian locations (Baisoara, Rosia Montana, Semenic, Ceahlau) and Nordic Optical Telescope (NOT) located at Observatorio del Roque de Los Muchachos, in the Canary Islands. Long term trends of microclimates have been compared in order to identify the site-to-site variations. We have performed this analysis as part of a site testing campaign aimed at finding the best location for the establishment of a small Cherenkov telescope in Romania. The conditions at the Romanian sites have been compared to those of the Canary Islands considered as a reference. A statistical approach has been used for data analysis. Monthly and annual samples have been extracted from series of raw data for nighttime, daytime and entire day intervals. Percentage distributions of meteorological parameters, whose values exceed certain limits, have been derived. Significant differences have been found between the Romanian sites and the NOT site. The comparison of the Romanian locations indicates Baisoara to be the best site for the establishment of the telescope, closely followed by Rosia Montana. As these two sites are both located in the Apuseni Mountains, we consider this area as the optimal place for performing astronomical observations in Romania.

A web application for follow-up of results from a mobile device test battery for Parkinson's disease patients

This paper describes a web-based system for enabling remote monitoring of patients with Parkinson's disease (PD) and supporting clinicians in treating their patients. The system consists of a patient node for subjective and objective data collection based on a handheld computer, a service node for data storage and processing, and a web application for data presentation. Using statistical and machine learning methods, time series of raw data are summarized into scores for conceptual symptom dimensions and an “overall test score” providing a comprehensive profile of patient's health during a test period of about one week. The handheld unit was used quarterly or biannually by 65 patients with advanced PD for up to four years at nine clinics in Sweden. The IBM Computer System Usability Questionnaire was administered to assess nurses’ satisfaction with the web application. Results showed that a majority of the nurses were quite satisfied with the usability although a sizeable minority were not. Our findings support that this system can become an efficient tool to easily access relevant symptom information from the home environment of PD patients.

Statistical inference for noisy nonlinear ecological dynamic systems

Chaotic ecological dynamic systems defy conventional statistical analysis. Systems with near-chaotic dynamics are little better. Such systems are almost invariably driven by endogenous dynamic processes plus demographic and environmental process noise, and are only observable with error. Their sensitivity to history means that minute changes in the driving noise realization, or the system parameters, will cause drastic changes in the system trajectory. This sensitivity is inherited and amplified by the joint probability density of the observable data and the process noise, rendering it useless as the basis for obtaining measures of statistical fit. Because the joint density is the basis for the fit measures used by all conventional statistical methods, this is a major theoretical shortcoming. The inability to make well-founded statistical inferences about biological dynamic models in the chaotic and near-chaotic regimes, other than on an ad hoc basis, leaves dynamic theory without the methods of quantitative validation that are essential tools in the rest of biological science. Here I show that this impasse can be resolved in a simple and general manner, using a method that requires only the ability to simulate the observed data on a system from the dynamic model about which inferences are required. The raw data series are reduced to phase-insensitive summary statistics, quantifying local dynamic structure and the distribution of observations. Simulation is used to obtain the mean and the covariance matrix of the statistics, given model parameters, allowing the construction of a 'synthetic likelihood' that assesses model fit. This likelihood can be explored using a straightforward Markov chain Monte Carlo sampler, but one further post-processing step returns pure likelihood-based inference. I apply the method to establish the dynamic nature of the fluctuations in Nicholson's classic blowfly experiments.

What Caused the Korean Currency Crisis in 1997?*: Weak Fundamentals or Self‐fulfilling Expectations*

The present paper investigates which factor is primarily responsible for the sharp depreciation of the Korean won against the US dollar in 1997, using a bivariate vector autoregressive model of real and nominal exchange rates. In the present study, we directly identify the relative importance of fundamental and non‐fundamental factors from the raw data series on exchange rates. This approach is different from most previous studies on the Korean currency crisis, which use proxy variables to represent the two factors. The empirical results show that the collapse of the Korean currency in 1997 appears to be mostly a result of the weakened macroeconomic fundamentals of the economy with, to a limited extent, some non‐fundamental factors.

A Bit Level Representation for Time Series Data Mining with Shape Based Similarity

Clipping is the process of transforming a real valued series into a sequence of bits representing whether each data is above or below the average. In this paper, we argue that clipping is a useful and flexible transformation for the exploratory analysis of large time dependent data sets. We demonstrate how time series stored as bits can be very efficiently compressed and manipulated and that, under some assumptions, the discriminatory power with clipped series is asymptotically equivalent to that achieved with the raw data. Unlike other transformations, clipped series can be compared directly to the raw data series. We show that this means we can form a tight lower bounding metric for Euclidean and Dynamic Time Warping distance and hence efficiently query by content. Clipped data can be used in conjunction with a host of algorithms and statistical tests that naturally follow from the binary nature of the data. A series of experiments illustrate how clipped series can be used in increasingly complex ways to achieve better results than other popular representations. The usefulness of the proposed representation is demonstrated by the fact that the results with clipped data are consistently better than those achieved with a Wavelet or Discrete Fourier Transformation at the same compression ratio for both clustering and query by content. The flexibility of the representation is shown by the fact that we can take advantage of a variable Run Length Encoding of clipped series to define an approximation of the Kolmogorov complexity and hence perform Kolmogorov based clustering.

Butterworth Low-Pass Filter for Processing Inertial Navigation System Raw Data

This article tries to apply the Butterworth low-pass filter to inertial navigation system (INS) data processing. A set of INS heading data of a practical example has been calculated and the filtering tested. This filtering method is used to examine the correction of the results made by Guo and Wang. Based on the discrete Fourier transformation and the digital filter design technique, a Butterworth low-pass digital filter has been designed and performed to process INS heading raw data. The design of a special Butterworth filter includes determination of the technical specification of the filter and of the response function in the time domain or the frequency domain (determination of the order and cutoff frequency of the digital filter). For the high-frequency noise of INS raw data, a Butterworth low-pass filter has been designed to obtain a more accurate INS heading. The choice of the parameters and orders of the filter is also discussed in the paper. Finally, an example of INS heading data calculation is presented. The signal-processing TOOLBOX of MATLAB software is used for calculating and mapping the results. The result (RMS) is at the level of 0.01 degrees. The method described here is simpler than Kalman filtering or the smoothing method and has sufficient accuracy for INS processing. It also provides ideas for some other series of raw data with high-frequency noise.

Streamed data - A source of insight and improvement for time domain airborne EM

The capacity to record streamed data, a time series of raw data from the transmitter current monitor and the electromagnetic sensors, was introduced to the QUESTEM 450 airborne EM system by the partners of the Airborne EM Systems Program at the CRC AMET during 1997. This has provided the opportunity to replay, analyse and reprocess data from any survey flown with the system. Much has been learnt about the various elements that contribute to the recorded response, and improvements have been made to the way in which the ground response is isolated from other unwanted influences.QUESTEM 450 is a time domain airborne EM system. A waveform with half-sine current pulses of alternating polarity is fed into a large horizontal transmitter loop slung around an aircraft. A three-component receiver coil set is towed in a bird behind the aircraft. Signals are sent from the bird to a receiver unit in the aircraft, where they are processed and recorded. Streamed data represents the most fundamental level of recorded data.The strongest contribution to the overall response is a combination of the voltage induced in the receiver coils from changes in the magnetic field associated with currents flowing in the transmitter loop and signals related to secondary currents induced in the metal frame of the aircraft. These two signals are never separated, and together make up the response termed the “primary”. The amplitude and shape of the primary varies as the transmitter to receiver loop geometry changes. Streamed data can reveal the effects of these changes in great detail.Another element of the response is related to the movement of the coil in the Earth’s magnetic field and is termed “coil motion noise”. This voltage will be induced under two circumstances; when the coil rotates with respect to the Earth’s field, and when the strength of the field varies at a rate within the pass band of the system. Computer-intensive processing methods applied post-flight to streamed data achieve higher levels of suppression of this form of noise than do methods traditionally applied onboard in real time.“Sferic” signals are the result of lightning strokes. Streamed data reveal that only the high amplitude, high frequency components of these signals are significant in the context of the present QUESTEM 450 system. A study of the character of these signals in streamed data resulted in an improvement to the method of suppression applied in real time on-board the aircraft.Powerlines radiate strong, time-varying magnetic fields which are visible in streamed data over very broad areas. The principal means of suppression for this element of the measured signal is a combination of careful choice of base frequency and stacking of the response. In the vicinity of a powerline, the amplitude of the response and/or the spatial variation in the field can significantly impair the ability to extract the ground response from the total response.

Consideration of the cephalometric data analysis applied to the Fourier Series (author's transl)

The purpose of this study was to examine the usefulness of the application of the Fourier Series for the morphological analysis in orthodontics.The sample consisted of serial cephalograms of 50 Japanese children taken at 7, 11 and 15 years of age. The shape of the mandible was expressed by the length and the angle from the midpoint of Me.-Ar. to each point along the lower border of the mandible. In order to eliminate the size factor, each mandible was standardized by using Me.-Ar.The suitability of the application of the Fourier Series for the analysis of the cephalometric data was proven to be effective from the following standpoint;1) Screening of the amount of information of the raw data series by using minimal coefficients.2) Statistically obtaining a mean curve representing a certain age, sex or type of occulusion, etc.. It can be a great advantage in making a comparative study.3) Classification of several different patterns with the pentagon diagram composed of five independent minimal coefficients.

Oscillatory Growth in Three Nations

Abstract Both the definition of economic activity and the definition of periodicity seem to determine whether there are long tides in economic affairs. Spectral analysis of growth rates finds no long waves in the U.S., U.K., and Sweden, but this is consistent with the appearance of long classical (upcross) swings in the deviations from trend of several raw data series. These upcross oscillations may not be independent components of economic evolution but merely distorted reflections of trend growth processes.