Jan Holub | Czech Technical University in Prague (original) (raw)

Papers by Jan Holub

Measurement: Sensors, Dec 1, 2021

Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

AHFE international, 2023

Perceiving the transmitted speech is a task that puts certain amount of cognitive load on the hum... more Perceiving the transmitted speech is a task that puts certain amount of cognitive load on the human brain. The degree of this load depends on several factors, e.g., the loudness of the perceived speech, the type and intensity of background noise, the quality and accent of the speech, familiarity with the topic of the message, etc. This load also varies between the native and non-native language (of the listener). Different levels of such load are manifested in longer duration workloads (e.g., during a work shift) by different levels of overall fatigue, which affects the decrease in the worker's action or decision error rate when performing other concurrent tasks (the so-called parallel-task paradigm). For technologies used in speech transmission or synthesis, e.g., in telecommunications, radio communications, and machine to human communications, the above implies a strong need to optimize the coding of human (or synthetic) voice to minimize listening effort during communication. Listening effort (LE) can be assessed by subjective tests following, e.g., ITU-T P.800 Recommendation, along with listening quality (LQ) as specified in P.800. A natural (but nowhere explicitely mentioned) requirement is that male and female voices are transferred with similar LQ and LE parameters; in other words, the transmission technology, including coding algorithms, frequency filters, or sampling rates, should not privilege one gender over the other to maintain similar working conditions and opportunities for all.The subjective test laboratory has performed gender analysis for all subjective test projects since 2018 to see how (mis)balanced the transmission quality between male and female speakers is. The identified misbalance can affect many professionals that deploy distant voice communication in their daily duties – think of female airport approach control dispatchers or other professionals (policewomen) who are principally handicapped by technological aspects of their job - worse voice transmission quality means higher listening effort is needed and may lead to consequent (subconscious) discomfort of their communication partners, or even intelligibility issues. Of course, this fact is not surprising for narrow-band or even old analog AM transmissions (as still used in AIRCOM). It can only be used as an argument to upgrade communication means to a suitable digital format. Unfortunately, some contemporary wide-band or even full-band digital communications also show statistically significant differences between quality of transferred male and female voices. The detailed results will be presented, including interesting systematic language dependencies (English, German, Mandarin).In the conclusions, suggestions for future codec designs considering the human-centric gender-balanced requirements are proposed. These include the minimum frequency response of the future coders, granularity of the perceptual frequency scaling, etc. Also, suggestions for gender neutrality of original (studio quality) recordings used to prepare the speech samples for the subjective tests are included.

IEEE Transactions on Instrumentation and Measurement, 2023

To automatically detect dangerous situations in public areas, systems based on visual detection a... more To automatically detect dangerous situations in public areas, systems based on visual detection are the most commonly used. In certain situations, to detect a source of danger, an automatic acoustic detection system may be preferable. This paper presents a smart acoustic sensor system, which automatically detects acoustic pulse events, such as gunshots, in public places, and localizes the position of the acoustic source. Tested firearms are 9 mm short gun, 6.35 mm short gun,. 22 short gun with various subsonic and supersonic ammunition. Various sounds like door slams, human screams, etc. represent false alarms.

Journal of physics, Nov 1, 2016

This paper deals with textual emotion classification which gained attention in recent years. Emot... more This paper deals with textual emotion classification which gained attention in recent years. Emotion classification is used in user experience, product evaluation, national security, and tutoring applications. It attempts to detect the emotional content in the input text and based on different approaches establish what kind of emotional content is present, if any. Textual emotion classification is the most difficult to handle, since it relies mainly on linguistic resources and it introduces many challenges to assignment of text to emotion represented by a proper model. A crucial part of each emotion detector is emotion model. Focus of this paper is to introduce emotion models used for classification. Categorical and dimensional models of emotion are explained and some more advanced approaches are mentioned.

The paper describes the Equivalent-Time Sampling (ETS) in Software-Defined Instruments (SDI)-typi... more The paper describes the Equivalent-Time Sampling (ETS) in Software-Defined Instruments (SDI)-typically oscilloscopes. It introduces a possible solution of the microcontrollers drawback caused by the maximal sampling frequency and its limitations in digitizing quick transient responses. The principle of ETS used in microcontrollers is explained, and the jitter effect is taken into account. Analog-to-digital converter input model and real properties of softwaredefined oscilloscope from ETS point of view are introduced and explained. In the system for circuit behavior analysis as a step response, where a microcontroller with internal peripherals (pulse-width modulation and analog-to-digital converter) is used for a test signal generation and data digitization, the use of ETS may increase the equivalent sampling rate of the internal analog-to-digital converter up to tens of MSa/s.

Journal of physics, Nov 1, 2016

A numerous techniques and algorithms are dedicated to extract emotions from input data. In our in... more A numerous techniques and algorithms are dedicated to extract emotions from input data. In our investigation it was stated that emotion-detection approaches can be classified into 3 following types: Keyword based / lexical-based, learning based, and hybrid. The most commonly used techniques, such as keyword-spotting method, Support Vector Machines, Naive Bayes Classifier, Hidden Markov Model and hybrid algorithms, have impressive results in this sphere and can reach more than 90% determining accuracy.

IEEE Access, 2021

This work involved human subjects in its research. Approval of all ethical and experimental proce... more This work involved human subjects in its research. Approval of all ethical and experimental procedures and protocols was granted by the Advisory Committee of the

Journal of The Audio Engineering Society, May 12, 2020

This article deals with subjective tests of speech intelligibility. A set of samples in Czechlang... more This article deals with subjective tests of speech intelligibility. A set of samples in Czechlanguage, recorded by four different narrators, was distorted with different noise levels andencoded by a low bit-rate encoder. The subjective test consisted of two parts. The first part(45 participants) proceeded according to the ITU-T Recommendation P.807 - Subjective testmethodology for assessing speech intelligibility. The second part (70 participants) included anadditional (parallel) psychomotor task deploying a laser-shooting simulator, where subjectshad the roles of “shooters” and “counters”. The purpose of the parallel task is to bring thetesting closer to the real use of technology. Significant differences have been found in theresults of the intelligibility of samples from different speakers. There were also differences inevaluation with and without a parallel task. Samples from male narrators have a significantlyhigher intelligibility score in the standard laboratory test, but also show a greater decrease inintelligibility after engaging a parallel task

Measurement: Sensors, Aug 1, 2022

IEEE Transactions on Instrumentation and Measurement, Oct 1, 2020

The distribution of indoor illuminance affects the health and the performance of humans and is, t... more The distribution of indoor illuminance affects the health and the performance of humans and is, therefore, subject to audits. Audits are performed after each modification of the light sources, and the currently adopted approach uses a human operator to perform measurements manually. This process is time-consuming, and we, therefore, aim to automate it with a mobile platform. In order to automate the process, we propose an online algorithm for selecting the control points. The algorithm is iterative, and it takes previous measurements into account in order to select the control points adaptively. We show how the proposed method can be combined with a mobile platform to perform the audit autonomously. Initially, the mobile platform, equipped with a laser range finder, is used to build the floor plan of the room. This floor plan is then used to restrict the area within which the control points can be selected. The whole measurement process is then executed without the presence or the intervention of a human operator, and this reduces the time needed for the audit. We have performed simulated and real experiments to demonstrate the performance of the proposed approach.

Transmission delays are unwanted effects of every day telecommunication systems. These effects in... more Transmission delays are unwanted effects of every day telecommunication systems. These effects influence the overall quality of a telephony connection as perceived by end users. This article summarizes known subjective experiments testing the influence of delays on the perceived quality. In order to find a possible explanation for the differences in the results of those experiments a new conversational test

The subject of the Industrial Electronics and Sensors Laboratory has been designed to be focused ... more The subject of the Industrial Electronics and Sensors Laboratory has been designed to be focused on the practical part of the teaching. Here we describe its concept, used equipment and task examples. Experience gathered during subject first run is reported, including final students' feedback.

Platform F0-Lab including LEO (Little Embedded Oscilloscope) was designed and developed to substi... more Platform F0-Lab including LEO (Little Embedded Oscilloscope) was designed and developed to substitute a professional set of instruments in experiments concerning electronics, measurement, and instrumentation. It is based on a microcontroller, which includes the sufficiently fast ADC. It enables to realize (in connection with PC) a simple DC voltmeter, a digitizing oscilloscope, a waveform recorder, and a PWM signal generator. The microcontroller can be placed in a solderless breadboard where the student realizes experimental circuits. The PC controls this virtual instrument, displaying results and supplying the power of the entire set using USB. F0-Lab is successfully used for three years and more than 300 various implementations have been already realized.

IEEE Access, 2018

This article reports subjective test results of two different test sets: one without and one with... more This article reports subjective test results of two different test sets: one without and one with a parallel task. The subjective listening tests were performed according to ITU-P.800 Recommendation. Regarding the parallel tasks, there were two categories: a parallel task that requires visual/motor coordination, and another that requires the use of taste perception. Specifically, in the first experiment, subjects were asked to drive a car simulator, while in the second they were asked to sort a variety of samples by taste. In both situations, the subjects performed the parallel task while assessing audio quality. The results obtained in the experiments with a parallel task showed considerable differences from the standard P.800 test. Nevertheless, similar features were observed in the results of both parallel task tests. Based on those results, an objective estimator of speech quality assessed with a parallel task was developed, which was based on an enhanced ITU-T P.863 (POLQA) algorithm. The improved estimator provides a more accurate prediction of subjective tests with a parallel task than the original POLQA algorithm, as shown also in the results.

Acta IMEKO, Dec 19, 2022

This article depicts how COVID-19 affected practical teaching at Czech Technical University in Pr... more This article depicts how COVID-19 affected practical teaching at Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Measurement. It introduces the subject of Electrical Measurement and its hands-on laboratory classes. The course applies to more than 100 undergraduate students per semester. Since COVID-19 mainly affected the teaching of the hands-on laboratory courses, the article narrates how the COVID-19 lockdown has changed classes. An experience with the rapid transformation of lectures during the lockdown focusing on the hands-on laboratory classes is discussed, and the improvements that have been done to preserve its objectives, but also to adapt them to another possible lockdown, and the need to switch to the distance teaching, is revealed. The changes have been inspired by the results of a survey carried out among more than 250 students. The outline of the laboratory tasks transformation with an emphasis on the possibility of switching the real face-to-face measurement to the distance teaching remote lectures is described. The change includes reducing the number of laboratory tasks taught while preserving most of the objectives. All 11 new laboratory tasks are described in detail, and it is discussed how the possible change from hands-on to remote classes will affect every task.

International Journal of Speech Technology, 2016

This article reports on a multi-lab subjective listening experiment aiming at inter-lab and intra... more This article reports on a multi-lab subjective listening experiment aiming at inter-lab and intra-lab test results repeatability verification. An identical set of speech samples corresponding to contemporary networks has been tested by three independent labs deploying ITU-T P.835 methodology. The tests results have been compared regarding Pearson correlation, RMSE, RMSE* and numbers of opposite pair-wise comparisons. The results show the level of inter-lab and intra-lab repeatability in the case of identical test speech samples utilization and thus confirm the subjective tests are highly repeatable in case they follow recommendation requirements strictly. The tests also show differences in results in case subject expectations are set differently using a wider set of test speech samples (as presented in one of the labs).

2008 Wireless Telecommunications Symposium, 2008

Measurement: Sensors, Dec 1, 2021

Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on ... more Elsevier has created a COVID-19 resource centre with free information in English and Mandarin on the novel coronavirus COVID-19. The COVID-19 resource centre is hosted on Elsevier Connect, the company's public news and information website. Elsevier hereby grants permission to make all its COVID-19-related research that is available on the COVID-19 resource centre-including this research content-immediately available in PubMed Central and other publicly funded repositories, such as the WHO COVID database with rights for unrestricted research re-use and analyses in any form or by any means with acknowledgement of the original source. These permissions are granted for free by Elsevier for as long as the COVID-19 resource centre remains active.

AHFE international, 2023

Perceiving the transmitted speech is a task that puts certain amount of cognitive load on the hum... more Perceiving the transmitted speech is a task that puts certain amount of cognitive load on the human brain. The degree of this load depends on several factors, e.g., the loudness of the perceived speech, the type and intensity of background noise, the quality and accent of the speech, familiarity with the topic of the message, etc. This load also varies between the native and non-native language (of the listener). Different levels of such load are manifested in longer duration workloads (e.g., during a work shift) by different levels of overall fatigue, which affects the decrease in the worker's action or decision error rate when performing other concurrent tasks (the so-called parallel-task paradigm). For technologies used in speech transmission or synthesis, e.g., in telecommunications, radio communications, and machine to human communications, the above implies a strong need to optimize the coding of human (or synthetic) voice to minimize listening effort during communication. Listening effort (LE) can be assessed by subjective tests following, e.g., ITU-T P.800 Recommendation, along with listening quality (LQ) as specified in P.800. A natural (but nowhere explicitely mentioned) requirement is that male and female voices are transferred with similar LQ and LE parameters; in other words, the transmission technology, including coding algorithms, frequency filters, or sampling rates, should not privilege one gender over the other to maintain similar working conditions and opportunities for all.The subjective test laboratory has performed gender analysis for all subjective test projects since 2018 to see how (mis)balanced the transmission quality between male and female speakers is. The identified misbalance can affect many professionals that deploy distant voice communication in their daily duties – think of female airport approach control dispatchers or other professionals (policewomen) who are principally handicapped by technological aspects of their job - worse voice transmission quality means higher listening effort is needed and may lead to consequent (subconscious) discomfort of their communication partners, or even intelligibility issues. Of course, this fact is not surprising for narrow-band or even old analog AM transmissions (as still used in AIRCOM). It can only be used as an argument to upgrade communication means to a suitable digital format. Unfortunately, some contemporary wide-band or even full-band digital communications also show statistically significant differences between quality of transferred male and female voices. The detailed results will be presented, including interesting systematic language dependencies (English, German, Mandarin).In the conclusions, suggestions for future codec designs considering the human-centric gender-balanced requirements are proposed. These include the minimum frequency response of the future coders, granularity of the perceptual frequency scaling, etc. Also, suggestions for gender neutrality of original (studio quality) recordings used to prepare the speech samples for the subjective tests are included.

IEEE Transactions on Instrumentation and Measurement, 2023

To automatically detect dangerous situations in public areas, systems based on visual detection a... more To automatically detect dangerous situations in public areas, systems based on visual detection are the most commonly used. In certain situations, to detect a source of danger, an automatic acoustic detection system may be preferable. This paper presents a smart acoustic sensor system, which automatically detects acoustic pulse events, such as gunshots, in public places, and localizes the position of the acoustic source. Tested firearms are 9 mm short gun, 6.35 mm short gun,. 22 short gun with various subsonic and supersonic ammunition. Various sounds like door slams, human screams, etc. represent false alarms.

Journal of physics, Nov 1, 2016

This paper deals with textual emotion classification which gained attention in recent years. Emot... more This paper deals with textual emotion classification which gained attention in recent years. Emotion classification is used in user experience, product evaluation, national security, and tutoring applications. It attempts to detect the emotional content in the input text and based on different approaches establish what kind of emotional content is present, if any. Textual emotion classification is the most difficult to handle, since it relies mainly on linguistic resources and it introduces many challenges to assignment of text to emotion represented by a proper model. A crucial part of each emotion detector is emotion model. Focus of this paper is to introduce emotion models used for classification. Categorical and dimensional models of emotion are explained and some more advanced approaches are mentioned.

The paper describes the Equivalent-Time Sampling (ETS) in Software-Defined Instruments (SDI)-typi... more The paper describes the Equivalent-Time Sampling (ETS) in Software-Defined Instruments (SDI)-typically oscilloscopes. It introduces a possible solution of the microcontrollers drawback caused by the maximal sampling frequency and its limitations in digitizing quick transient responses. The principle of ETS used in microcontrollers is explained, and the jitter effect is taken into account. Analog-to-digital converter input model and real properties of softwaredefined oscilloscope from ETS point of view are introduced and explained. In the system for circuit behavior analysis as a step response, where a microcontroller with internal peripherals (pulse-width modulation and analog-to-digital converter) is used for a test signal generation and data digitization, the use of ETS may increase the equivalent sampling rate of the internal analog-to-digital converter up to tens of MSa/s.

Journal of physics, Nov 1, 2016

A numerous techniques and algorithms are dedicated to extract emotions from input data. In our in... more A numerous techniques and algorithms are dedicated to extract emotions from input data. In our investigation it was stated that emotion-detection approaches can be classified into 3 following types: Keyword based / lexical-based, learning based, and hybrid. The most commonly used techniques, such as keyword-spotting method, Support Vector Machines, Naive Bayes Classifier, Hidden Markov Model and hybrid algorithms, have impressive results in this sphere and can reach more than 90% determining accuracy.

IEEE Access, 2021

This work involved human subjects in its research. Approval of all ethical and experimental proce... more This work involved human subjects in its research. Approval of all ethical and experimental procedures and protocols was granted by the Advisory Committee of the

Journal of The Audio Engineering Society, May 12, 2020

This article deals with subjective tests of speech intelligibility. A set of samples in Czechlang... more This article deals with subjective tests of speech intelligibility. A set of samples in Czechlanguage, recorded by four different narrators, was distorted with different noise levels andencoded by a low bit-rate encoder. The subjective test consisted of two parts. The first part(45 participants) proceeded according to the ITU-T Recommendation P.807 - Subjective testmethodology for assessing speech intelligibility. The second part (70 participants) included anadditional (parallel) psychomotor task deploying a laser-shooting simulator, where subjectshad the roles of “shooters” and “counters”. The purpose of the parallel task is to bring thetesting closer to the real use of technology. Significant differences have been found in theresults of the intelligibility of samples from different speakers. There were also differences inevaluation with and without a parallel task. Samples from male narrators have a significantlyhigher intelligibility score in the standard laboratory test, but also show a greater decrease inintelligibility after engaging a parallel task

Measurement: Sensors, Aug 1, 2022

IEEE Transactions on Instrumentation and Measurement, Oct 1, 2020

The distribution of indoor illuminance affects the health and the performance of humans and is, t... more The distribution of indoor illuminance affects the health and the performance of humans and is, therefore, subject to audits. Audits are performed after each modification of the light sources, and the currently adopted approach uses a human operator to perform measurements manually. This process is time-consuming, and we, therefore, aim to automate it with a mobile platform. In order to automate the process, we propose an online algorithm for selecting the control points. The algorithm is iterative, and it takes previous measurements into account in order to select the control points adaptively. We show how the proposed method can be combined with a mobile platform to perform the audit autonomously. Initially, the mobile platform, equipped with a laser range finder, is used to build the floor plan of the room. This floor plan is then used to restrict the area within which the control points can be selected. The whole measurement process is then executed without the presence or the intervention of a human operator, and this reduces the time needed for the audit. We have performed simulated and real experiments to demonstrate the performance of the proposed approach.

Transmission delays are unwanted effects of every day telecommunication systems. These effects in... more Transmission delays are unwanted effects of every day telecommunication systems. These effects influence the overall quality of a telephony connection as perceived by end users. This article summarizes known subjective experiments testing the influence of delays on the perceived quality. In order to find a possible explanation for the differences in the results of those experiments a new conversational test

The subject of the Industrial Electronics and Sensors Laboratory has been designed to be focused ... more The subject of the Industrial Electronics and Sensors Laboratory has been designed to be focused on the practical part of the teaching. Here we describe its concept, used equipment and task examples. Experience gathered during subject first run is reported, including final students' feedback.

Platform F0-Lab including LEO (Little Embedded Oscilloscope) was designed and developed to substi... more Platform F0-Lab including LEO (Little Embedded Oscilloscope) was designed and developed to substitute a professional set of instruments in experiments concerning electronics, measurement, and instrumentation. It is based on a microcontroller, which includes the sufficiently fast ADC. It enables to realize (in connection with PC) a simple DC voltmeter, a digitizing oscilloscope, a waveform recorder, and a PWM signal generator. The microcontroller can be placed in a solderless breadboard where the student realizes experimental circuits. The PC controls this virtual instrument, displaying results and supplying the power of the entire set using USB. F0-Lab is successfully used for three years and more than 300 various implementations have been already realized.

IEEE Access, 2018

This article reports subjective test results of two different test sets: one without and one with... more This article reports subjective test results of two different test sets: one without and one with a parallel task. The subjective listening tests were performed according to ITU-P.800 Recommendation. Regarding the parallel tasks, there were two categories: a parallel task that requires visual/motor coordination, and another that requires the use of taste perception. Specifically, in the first experiment, subjects were asked to drive a car simulator, while in the second they were asked to sort a variety of samples by taste. In both situations, the subjects performed the parallel task while assessing audio quality. The results obtained in the experiments with a parallel task showed considerable differences from the standard P.800 test. Nevertheless, similar features were observed in the results of both parallel task tests. Based on those results, an objective estimator of speech quality assessed with a parallel task was developed, which was based on an enhanced ITU-T P.863 (POLQA) algorithm. The improved estimator provides a more accurate prediction of subjective tests with a parallel task than the original POLQA algorithm, as shown also in the results.

Acta IMEKO, Dec 19, 2022

This article depicts how COVID-19 affected practical teaching at Czech Technical University in Pr... more This article depicts how COVID-19 affected practical teaching at Czech Technical University in Prague, Faculty of Electrical Engineering, Department of Measurement. It introduces the subject of Electrical Measurement and its hands-on laboratory classes. The course applies to more than 100 undergraduate students per semester. Since COVID-19 mainly affected the teaching of the hands-on laboratory courses, the article narrates how the COVID-19 lockdown has changed classes. An experience with the rapid transformation of lectures during the lockdown focusing on the hands-on laboratory classes is discussed, and the improvements that have been done to preserve its objectives, but also to adapt them to another possible lockdown, and the need to switch to the distance teaching, is revealed. The changes have been inspired by the results of a survey carried out among more than 250 students. The outline of the laboratory tasks transformation with an emphasis on the possibility of switching the real face-to-face measurement to the distance teaching remote lectures is described. The change includes reducing the number of laboratory tasks taught while preserving most of the objectives. All 11 new laboratory tasks are described in detail, and it is discussed how the possible change from hands-on to remote classes will affect every task.

International Journal of Speech Technology, 2016

This article reports on a multi-lab subjective listening experiment aiming at inter-lab and intra... more This article reports on a multi-lab subjective listening experiment aiming at inter-lab and intra-lab test results repeatability verification. An identical set of speech samples corresponding to contemporary networks has been tested by three independent labs deploying ITU-T P.835 methodology. The tests results have been compared regarding Pearson correlation, RMSE, RMSE* and numbers of opposite pair-wise comparisons. The results show the level of inter-lab and intra-lab repeatability in the case of identical test speech samples utilization and thus confirm the subjective tests are highly repeatable in case they follow recommendation requirements strictly. The tests also show differences in results in case subject expectations are set differently using a wider set of test speech samples (as presented in one of the labs).

2008 Wireless Telecommunications Symposium, 2008