Ján Šaliga

Bio: Ján Šaliga is an academic researcher from Technical University of Košice. The author has contributed to research in topics: Signal & Compressed sensing. The author has an hindex of 11, co-authored 50 publications receiving 398 citations.

Combined spectral and histogram analysis for fast ADC testing

Abstract: The integral nonlinearity (INL) of analog-to-digital converters (ADCs) can be described by a behavioral error model expressed as one-dimensional image in the code domain. This image consists of low and high code frequency components which allow describing the ADC performance with a small number of parameters. This paper presents new methods for low code frequency and high code frequency testing. The identification of the low code frequency components is performed by multiharmonic sine fitting in the time domain. The high code frequency components are estimated in the statistical domain by a narrow band histogram test using a triangular stimulus signal. The performance of the proposed method is assessed for various ADC devices.

DNL ADC testing by the exponential shaped voltage

Abstract: Testing of ADC differential nonlinearity by the histogram method requires a signal generator with extremely low distortion and high stability. In this paper, the new type of stimulus signal is proposed, which simplifies the task. The testing signal has an exponential form and can be generated simply by discharging the capacitor across the resistance. The resulting digital samples from the output of the tested ADC allow estimation of the best fitted exponential signal by the proper three-parameter method. The histograms from the data record and from the best fitted exponential approximation allow calculation of the differential nonlinearity.

Volterra filtering for integrating ADC error correction, based on an a priori error model

Abstract: Dynamic nonlinear effects contribute significantly to analog-to-digital converters (ADCs) distortion. Volterra filtering can present an effective method for modeling and compensation of these phenomena. Considering an a priori error model of ADC allows us to find an efficient inverse Volterra model for error correction. The method's effectiveness is demonstrated by experimental measurements.

Remote patient monitoring: a comprehensive study

Abstract: Healthcare is a field that is rapidly developing in technology and services. A recent development in this area is remote monitoring of patients which has many advantages in a fast aging world population with increasing health complications. With relatively simple applications to monitor patients inside hospital rooms, the technology has developed to the extent that the patient can be allowed normal daily activities at home while still being monitored with the use of modern communication and sensor technologies. Sensors for monitoring essential vital signs such as electrocardiogram reading, heart rate, respiration rate, blood pressure, temperature, blood glucose levels and neural system activity are available today. Range of remote healthcare varies from monitoring chronically ill patients, elders, premature children to victims of accidents. These new technologies can monitor patients based on the illness or based on the situation. The technology varies from sensors attached to body to ambient sensors attached to the environment and new breakthroughs show contactless monitoring which requires only the patient to be present within a few meters from the sensor. Fall detection systems and applications to monitor chronical ill patients have already become familiar to many. This study provides a review of the recent advances in remote healthcare and monitoring in both with-contact and contactless methods. With the review, the authors discuss some issues available in most systems. The paper also includes some directions for future research.

Laser trackers for large-scale dimensional metrology: A review

Abstract: Thirty years since their invention, laser trackers are now recognized as the measurement tool of choice in the manufacture and assembly of large components. The general design of laser trackers, i.e., a ranging unit on a two-axis gimbal, has not changed significantly over the years. However, innovations in ranging technology, for example, the emergence of increasingly accurate absolute distance meters (ADMs), are providing users with an alternative to interferometers (IFMs). Hand-held accessories such as touch probes and line scanners are expanding the scope and applicability of laser trackers. In this paper, we survey the literature in all areas of laser trackers as applied to large-scale dimensional metrology (LSDM), with emphasis on error modeling, measurement uncertainty, performance evaluation and standardization.

A state of the art on ADC error compensation methods

Abstract: Analog-to-digital converters (ADCs) are critical components of signal-processing systems. ADC errors can compromise the overall accuracy and the effectiveness of the whole system. This leads researchers to direct increasing attention to error correction topics. In this paper, some ADC error compensation methods are briefly introduced according to a classification criterion based on the main research trends.

Effects of soiling on photovoltaic (PV) modules in the Atacama Desert.

Abstract: Soiling by dry deposition affects the power output of photovoltaic (PV) modules, especially under dry and arid conditions that favor natural atmospheric aerosols (wind-blown dust) In this paper, we report on measurements of the soiling effect on the energy yield of grid-connected crystalline silicon PV modules deployed in five cities across a north-south transect of approximately 1300 km in the Atacama Desert ranging from latitude 18°S to latitude 30°S Energy losses were assessed by comparing side-by-side outputs of four co-planar PV modules Two of the PV modules of the array were kept clean as a control, while we allowed the other two to naturally accumulate soiling for 12 months (from January 2017 to January 2018) We found that the combination of high deposition rates and infrequent rainfalls led to annual energy losses that peaked at 39% in the northern coastal part of the desert In contrast, annual energy losses of 3% or less were measured at relatively high-altitude sites and also at locations in the southern part of the desert For comparison, soiling-induced annual energy losses of about 7% were measured in Santiago, Chile (33°S), a major city with higher rainfall frequency but where urban pollution plays a significant role

An evaluation and selection problems of OSS-LMS packages.

Abstract: The evaluation and selection of inappropriate open source software in learning management system (OSS-LMS) packages adversely affect the business processes and functions of an organization. Thus, comprehensive insights into the evaluation and selection of OSS-LMS packages are presented in this paper on the basis of three directions. First, available OSS-LMSs are ascertained from published papers. Second, the criteria for evaluating OSS-LMS packages are specified.according to two aspects: the criteria are identified and established, followed by a crossover between them to highlight the gaps between the evaluation criteria for OSS-LMS packages and the selection problems. Third, the abilities of selection methods that appear fit to solve the problems of OSS-LMS packages based on the multi-criteria evaluation and selection problem are discussed to select the best OSS-LMS packages. Results indicate the following: (1) a list of active OSS-LMS packages; (2) the gaps on the evaluation criteria used for LMS and other problems (consisting of main groups with sub-criteria); (3) use of multi-attribute or multi-criteria decision-making (MADM/MCDM) techniques in the framework of the evaluation and selection of the OSS in education as recommended solutions.