Search results

1

Settling Time Testing of Fast DACs

100%

Kvedaras R., Kvedaras V., Ustinavicius T.

Acta Physica Polonica A

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2011

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vol. 119

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issue 4

521-527

EN

New specialized sampling converter for signal timescale transformation and algorithm of digital signal processing for automated measurement of settling times of fast digital-to-analogue converters is represented. The new sampling device with numerically controlled oscillators allows us realization of different types of the timescale transformation. Usage of ΣΔ analogue-to-digital converter and first-in first-out memory allows us significant simplification of the device. The equations of timescale transformation ratio and sampling step are presented. A method using a brick-wall comb filter in frequency domain to filter measurement signal has been developed. It is shown that such filtering allows us significant reduction of noise of measurement signal. A new method and algorithm using a brick-wall comb filter and averaging of filtered signal has been developed. Results of the research of developed digital signal processing algorithm are submitted.

2

Statistical Analysis of Emotions and Opinions at Digg Website

100%

Pohorecki P., Sienkiewicz J., Mitrović M., Paltoglou G., Hołyst J.

Acta Physica Polonica A

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2013

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vol. 123

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issue 3

604-615

EN

We performed statistical analysis on data from the Digg.com website, which enables its users to express their opinion on news stories by taking part in forum-like discussions as well as to directly evaluate previous posts and stories by assigning so called "diggs". Owing to fact that the content of each post has been annotated with its emotional value, apart from the strictly structural properties, the study also includes an analysis of the average emotional response of the comments about the main story. While analysing correlations at the story level, an interesting relationship between the number of diggs and the number of comments that a story received was found. The correlation between the two quantities is high for data where small threads dominate and consistently decreases for longer threads. However, while the correlation of the number of diggs and the average emotional response tends to grow for longer threads, correlations between numbers of comments and the average emotional response are almost zero. We also suggest presence of two different mechanisms governing the evolution of the discussion and, consequently, its length.

3

Stability and Performance Characteristics of a Digital Positron Lifetime Spectrometer

100%

Aavikko R., Rytsölä K., Nissilä J., Saarinen K.

Acta Physica Polonica A

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2005

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vol. 107

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issue 4

592-597

EN

We summarize the setup and performance tests of a digital positron lifetime spectrometer presently in routine use at HUT/Laboratory of Physics. The performance of the spectrometer is found to be equal to or better than that of an analog spectrometer with similar detectors. We present also results on measuring the stability of the system, which is found to be similar to that of analog spectrometers: variation in the time-zero of the spectrometer is found to be ≈10 ps/week. We suggest that the remaining instabilities of the spectrometers originate primarily from the detectors.

4

Emotional Analysis of Blogs and Forums Data

100%

Weroński P., Sienkiewicz J., Paltoglou G., Buckley K., Thelwall M., Hołyst J.

Acta Physica Polonica A

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2012

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vol. 121

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issue 2B

B-128-B-132

EN

We perform a statistical analysis of emotionally annotated comments in two large online datasets, examining chains of consecutive posts in the discussions. Using comparisons with randomised data we show that there is a high level of correlation for the emotional content of messages.

5

The Role of Emotional Variables in the Classification and Prediction of Collective Social Dynamics

100%

Chołoniewski J., Sienkiewicz J., Hołyst J., Thelwall M.

Acta Physica Polonica A

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2015

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vol. 127

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issue 3A

A-21-A-28

EN

We demonstrate the power of data mining techniques for the analysis of collective social dynamics within British Tweets during the Olympic Games 2012. The classification accuracy of online activities related to the successes of British athletes significantly improved when emotional components of tweets were taken into account, but employing emotional variables for activity prediction decreased the classifiers' quality. The approach could be easily adopted for any prediction or classification study with a set of problem-specific variables.

6

Analysis of EGNOS-Augmented GPS Receiver Positioning Accuracy

100%

Skorkowski A., Topór-Kamiński T.

Acta Physica Polonica A

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2012

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vol. 122

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issue 5

821-824

EN

This study presents the operation basis of GPS global positioning system and augmentation systems used to increase positioning accuracy. Furthermore, selected measurement results for an EGNOS-augmented GPS receiver positioning are included along with an analysis of GIS measurements accuracy, performed using differential corrections. This analysis takes into consideration the impact of the number of measurement series and satellite constellation on the accuracy of positioning achieved in praxis using the EGNOS system.

7

Design of a Single Line Half Duplex Protocol for Mechanical Rotary Table Systems

88%

Ozkan S., Atali G., Boru B., Karayel D.

Acta Physica Polonica A

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2017

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vol. 132

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issue 3

749-752

EN

In this study, a new communication protocol, which addresses the rotary table, has been designed. Developed system works over a single line and is using slip rings. The designed communication protocol ensures the half duplex communication for multiple stations over a single cable. During the protocol design, media access methods, coding techniques and multi-node synchronization techniques were examined. These techniques have been adapted, updated and combined for the study, during the formation of the communication protocol. The designed protocol was tested and verified in the simulation environment with original software, on the microcontrollers. The protocol is aimed to be open source, flexible, easily applicable and a new solution for the distributed control problems in the field of automation and for the rotary table systems in particular.

8

Selected Methods of Measuring the Delay in Data Transmission Systems with Wireless Network Interfaces

88%

Topor-Kaminski T., Żurkowski R., Grygiel M.

Acta Physica Polonica A

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2011

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vol. 120

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issue 4

748-754

EN

The article presents the concept of creating model of delays occurring in telecommunication system taking into account all sources of delays generated during data transmission between the source and destination nodes. Proposed model takes into account the existence of intermediary network devices that play a significant role in the general delay budget. The paper presents two measurement systems used to measure delays in 802.11 g based wireless networks and ones using ZigBee standard. Both systems were built based on the authors' concepts of hardware and software allowing measurement of delays by using additional connection for the synchronization of internal clocks. Described measurement systems selected amount of experiments was performed for varied network structures.

Refine search results

Settling Time Testing of Fast DACs

Statistical Analysis of Emotions and Opinions at Digg Website

Stability and Performance Characteristics of a Digital Positron Lifetime Spectrometer

Emotional Analysis of Blogs and Forums Data

The Role of Emotional Variables in the Classification and Prediction of Collective Social Dynamics

Analysis of EGNOS-Augmented GPS Receiver Positioning Accuracy

Design of a Single Line Half Duplex Protocol for Mechanical Rotary Table Systems

Selected Methods of Measuring the Delay in Data Transmission Systems with Wireless Network Interfaces