The split attention problem and its implications for the design of e-Learning material have been ... more The split attention problem and its implications for the design of e-Learning material have been subject to a large number of empirical studies. How results of these studies can be applied to the design of web lecture interfaces is, however, still an issue of debate. Findings are at first glance contradictory and it seems that it is impossible to establish
ICM'99. Proceedings. Eleventh International Conference on Microelectronics (IEEE Cat. No.99EX388), 2000
The purpose of this paper is twofold. Firstly, it presents a concise overview of the benefits to ... more The purpose of this paper is twofold. Firstly, it presents a concise overview of the benefits to be expected from the development of a thin-film crystalline Si solar cell technology on a low-cost substrate as well as the technical and physical challenges encountered. It becomes clear that a large number of options are open in terms of substrate, deposition technology
The propagation delay T of an Emitter-Coupled-Logic (ECL) gate is studied as a function of the di... more The propagation delay T of an Emitter-Coupled-Logic (ECL) gate is studied as a function of the different device aind circuit. parameters involved. It is found that the delay in the response of the switching transistor is the dominant delay component. The propagation delay is highly sensitive to the change in the cut-off frequency and the magnitude of the current source.
In this work the bandgap narrowing due to heavy doping in SiGe alloys is calculated using first-o... more In this work the bandgap narrowing due to heavy doping in SiGe alloys is calculated using first-order models at T=OK. A detailed overview of the way we have proceeded is given as well as a clarification of the different assumptions. Results are presented for n and p type doping, indicating that the values for the bandgap narrowing are approximately the
Proceedings of the 1988 Bipolar Circuits and Technology Meeting,, 1988
The effect of heavy doping on the capacitance-voltage relation of abrupt and linearly-graded p-n ... more The effect of heavy doping on the capacitance-voltage relation of abrupt and linearly-graded p-n junctions is studied by computer simulations. An estimate of bandgap narrowing in compensated silicon is given for linearly-graded junctions. Capacitance-voltage curves of abrupt p-n GaAs junctions grown by MBE are investigated and compared to the theoretical curves
Proceedings of the 30th European Solid-State Circuits Conference (IEEE Cat. No.04EX850), 2004
Band-gap narrowing (BGN) is determined in heavily doped n-type GaAs and n-type Ga0.5In0.5P from e... more Band-gap narrowing (BGN) is determined in heavily doped n-type GaAs and n-type Ga0.5In0.5P from experimental pn junction solar cell performance. A BGN of 82 meV and of 17 meV is determined in GaAs with an n-type doping concentration of 2×1018/cm3 and 1017/cm3, respectively, and an average 95 meV BGN is determined in Ga0.5In0.5P with an n-type doping concentration of 3×1018/cm3.
An analogy is made between silicon thin film splitting from porous silicon annealed in hydrogen a... more An analogy is made between silicon thin film splitting from porous silicon annealed in hydrogen at temperature around or higher than 1000oC, and silicon film splitting (exfoliation) due to defects induced deep in the substrate by hydrogenation (hydrogen induced defects, HID) and annealed in the temperature range 650oC to 900oC. The minimum density of hydrogen gas molecules needed to drive the HID to a crack is in the range 1016 /cm2 which is likely to occur during annealing in hydrogen at high temperature. The physical/mechanical and chemical roles of hydrogen in favoring the splitting process in both cases are examined theoretically and supported by reported experimental observations. Hydrogen supersaturation is declared responsible for exfoliation and promoting silicon film splitting during porous silicon annealing. It is shown that hydrogen has a dual role in favoring film splitting and exfoliation since 1) it favors void growth as it helps reducing the surface energy by replacin...
We report on the fabrication and characterization of solar blind Metal-Semiconductor-Metal (MSM) ... more We report on the fabrication and characterization of solar blind Metal-Semiconductor-Metal (MSM) based photodetectors for use in the extreme ultraviolet (EUV) wavelength range. The devices were fabricated in the AlGaN-on- Si material system, with Aluminum Gallium Nitride (AlGaN) epitaxial layers grown on Si(111) by means of Molecular Beam Epitaxy. The detectors' IV characteristics and photoresponse were measured between 200 and
E-Learning plays an increasingly important role in modern university teaching. One fast and easy ... more E-Learning plays an increasingly important role in modern university teaching. One fast and easy way to produce high-quality content for selected E-Learning scenarios is broadcasting and recording lectures and seminars. Due to cost-efficiency in courses shared by two or more universities and the possibility to communicate with experts from far-away locations, broadcasting technologies such as video-/audio-conferencing provide an attractive addition to live courses. For conventional lectures, recordings have proven to be valuable as they make it possible to repeat important parts of the lecture for students, who were unable to attend or for those who did not grasp specific topics during the lecture. For most lecturers however, these new technologies are hard to use since they require constant attention and specialised technical knowledge. It is thus crucially important to reduce technology-interaction during recording and broadcasting in order to facilitate the use of these promising...
Given the exponential growth of videos published on the Internet, mechanisms for clustering, sear... more Given the exponential growth of videos published on the Internet, mechanisms for clustering, searching, and browsing large numbers of videos have become a major research area. More importantly, there is a demand for event detectors that go beyond the simple finding of objects but rather detect more abstract concepts, such as "feeding an animal" or a "wedding ceremony". This article presents an approach for event classification that enables searching for arbitrary events, including more abstract concepts, in found video collections based on the analysis of the audio track. The approach does not rely on speech processing, and is language-indepent, instead it generates models for a set of example query videos using a mixture of two types of audio features: Linear-Frequency Cepstral Coefficients and Modulation Spectrogram Features. This approach can be used in complement with video analysis and requires no domain specific tagging. Application of the approach to the T...
Recently, audio concepts emerged as a useful building block in multimodal video retrieval systems... more Recently, audio concepts emerged as a useful building block in multimodal video retrieval systems. Information like "this file contains laughter", "this file contains engine sounds" or "this file contains slow music" can significantly improve purely visual based retrieval. The weak point of current approaches to audio concept detection is that they heavily rely on human annotators. In most approaches, audio material is manually inspected to identify relevant concepts. Then instances that contain examples of relevant concepts are selected -- again manually -- and used to train concept detectors. This approach comes with two major disadvantages: (1) it leads to rather abstract audio concepts that hardly cover the audio domain at hand and (2) the way human annotators identify audio concepts likely differs from the way a computer algorithm clusters audio data -- introducing additional noise in training data. This paper explores whether unsupervized audio se...
Acoustics, Speech, and Signal Processing, 1988. ICASSP-88., 1988 International Conference on
This paper presents a system that uses symbolic representa-tions of audio concepts as words for t... more This paper presents a system that uses symbolic representa-tions of audio concepts as words for the descriptions of au-dio tracks, that enable it to go beyond the state of the art, which is audio event classification of a small number of au-dio classes in constrained settings, to large-scale classifica-tion in the wild. These audio words might be less mean-ingful for an annotator but they are descriptive for computer algorithms. We devise a random-forest vocabulary learning method with an audio word weighting scheme based on TF-IDF and TD-IDD, so as to combine the computational sim-plicity and accurate multi-class classification of the random forest with the data-driven discriminative power of the TF-IDF/TD-IDD methods. The proposed random forest cluster-ing with text-retrieval methods significantly outperforms two state-of-the-art methods on the dry-run set and the full set of the TRECVID MED 2010 dataset.
The split attention problem and its implications for the design of e-Learning material have been ... more The split attention problem and its implications for the design of e-Learning material have been subject to a large number of empirical studies. How results of these studies can be applied to the design of web lecture interfaces is, however, still an issue of debate. Findings are at first glance contradictory and it seems that it is impossible to establish
ICM'99. Proceedings. Eleventh International Conference on Microelectronics (IEEE Cat. No.99EX388), 2000
The purpose of this paper is twofold. Firstly, it presents a concise overview of the benefits to ... more The purpose of this paper is twofold. Firstly, it presents a concise overview of the benefits to be expected from the development of a thin-film crystalline Si solar cell technology on a low-cost substrate as well as the technical and physical challenges encountered. It becomes clear that a large number of options are open in terms of substrate, deposition technology
The propagation delay T of an Emitter-Coupled-Logic (ECL) gate is studied as a function of the di... more The propagation delay T of an Emitter-Coupled-Logic (ECL) gate is studied as a function of the different device aind circuit. parameters involved. It is found that the delay in the response of the switching transistor is the dominant delay component. The propagation delay is highly sensitive to the change in the cut-off frequency and the magnitude of the current source.
In this work the bandgap narrowing due to heavy doping in SiGe alloys is calculated using first-o... more In this work the bandgap narrowing due to heavy doping in SiGe alloys is calculated using first-order models at T=OK. A detailed overview of the way we have proceeded is given as well as a clarification of the different assumptions. Results are presented for n and p type doping, indicating that the values for the bandgap narrowing are approximately the
Proceedings of the 1988 Bipolar Circuits and Technology Meeting,, 1988
The effect of heavy doping on the capacitance-voltage relation of abrupt and linearly-graded p-n ... more The effect of heavy doping on the capacitance-voltage relation of abrupt and linearly-graded p-n junctions is studied by computer simulations. An estimate of bandgap narrowing in compensated silicon is given for linearly-graded junctions. Capacitance-voltage curves of abrupt p-n GaAs junctions grown by MBE are investigated and compared to the theoretical curves
Proceedings of the 30th European Solid-State Circuits Conference (IEEE Cat. No.04EX850), 2004
Band-gap narrowing (BGN) is determined in heavily doped n-type GaAs and n-type Ga0.5In0.5P from e... more Band-gap narrowing (BGN) is determined in heavily doped n-type GaAs and n-type Ga0.5In0.5P from experimental pn junction solar cell performance. A BGN of 82 meV and of 17 meV is determined in GaAs with an n-type doping concentration of 2×1018/cm3 and 1017/cm3, respectively, and an average 95 meV BGN is determined in Ga0.5In0.5P with an n-type doping concentration of 3×1018/cm3.
An analogy is made between silicon thin film splitting from porous silicon annealed in hydrogen a... more An analogy is made between silicon thin film splitting from porous silicon annealed in hydrogen at temperature around or higher than 1000oC, and silicon film splitting (exfoliation) due to defects induced deep in the substrate by hydrogenation (hydrogen induced defects, HID) and annealed in the temperature range 650oC to 900oC. The minimum density of hydrogen gas molecules needed to drive the HID to a crack is in the range 1016 /cm2 which is likely to occur during annealing in hydrogen at high temperature. The physical/mechanical and chemical roles of hydrogen in favoring the splitting process in both cases are examined theoretically and supported by reported experimental observations. Hydrogen supersaturation is declared responsible for exfoliation and promoting silicon film splitting during porous silicon annealing. It is shown that hydrogen has a dual role in favoring film splitting and exfoliation since 1) it favors void growth as it helps reducing the surface energy by replacin...
We report on the fabrication and characterization of solar blind Metal-Semiconductor-Metal (MSM) ... more We report on the fabrication and characterization of solar blind Metal-Semiconductor-Metal (MSM) based photodetectors for use in the extreme ultraviolet (EUV) wavelength range. The devices were fabricated in the AlGaN-on- Si material system, with Aluminum Gallium Nitride (AlGaN) epitaxial layers grown on Si(111) by means of Molecular Beam Epitaxy. The detectors' IV characteristics and photoresponse were measured between 200 and
E-Learning plays an increasingly important role in modern university teaching. One fast and easy ... more E-Learning plays an increasingly important role in modern university teaching. One fast and easy way to produce high-quality content for selected E-Learning scenarios is broadcasting and recording lectures and seminars. Due to cost-efficiency in courses shared by two or more universities and the possibility to communicate with experts from far-away locations, broadcasting technologies such as video-/audio-conferencing provide an attractive addition to live courses. For conventional lectures, recordings have proven to be valuable as they make it possible to repeat important parts of the lecture for students, who were unable to attend or for those who did not grasp specific topics during the lecture. For most lecturers however, these new technologies are hard to use since they require constant attention and specialised technical knowledge. It is thus crucially important to reduce technology-interaction during recording and broadcasting in order to facilitate the use of these promising...
Given the exponential growth of videos published on the Internet, mechanisms for clustering, sear... more Given the exponential growth of videos published on the Internet, mechanisms for clustering, searching, and browsing large numbers of videos have become a major research area. More importantly, there is a demand for event detectors that go beyond the simple finding of objects but rather detect more abstract concepts, such as "feeding an animal" or a "wedding ceremony". This article presents an approach for event classification that enables searching for arbitrary events, including more abstract concepts, in found video collections based on the analysis of the audio track. The approach does not rely on speech processing, and is language-indepent, instead it generates models for a set of example query videos using a mixture of two types of audio features: Linear-Frequency Cepstral Coefficients and Modulation Spectrogram Features. This approach can be used in complement with video analysis and requires no domain specific tagging. Application of the approach to the T...
Recently, audio concepts emerged as a useful building block in multimodal video retrieval systems... more Recently, audio concepts emerged as a useful building block in multimodal video retrieval systems. Information like "this file contains laughter", "this file contains engine sounds" or "this file contains slow music" can significantly improve purely visual based retrieval. The weak point of current approaches to audio concept detection is that they heavily rely on human annotators. In most approaches, audio material is manually inspected to identify relevant concepts. Then instances that contain examples of relevant concepts are selected -- again manually -- and used to train concept detectors. This approach comes with two major disadvantages: (1) it leads to rather abstract audio concepts that hardly cover the audio domain at hand and (2) the way human annotators identify audio concepts likely differs from the way a computer algorithm clusters audio data -- introducing additional noise in training data. This paper explores whether unsupervized audio se...
Acoustics, Speech, and Signal Processing, 1988. ICASSP-88., 1988 International Conference on
This paper presents a system that uses symbolic representa-tions of audio concepts as words for t... more This paper presents a system that uses symbolic representa-tions of audio concepts as words for the descriptions of au-dio tracks, that enable it to go beyond the state of the art, which is audio event classification of a small number of au-dio classes in constrained settings, to large-scale classifica-tion in the wild. These audio words might be less mean-ingful for an annotator but they are descriptive for computer algorithms. We devise a random-forest vocabulary learning method with an audio word weighting scheme based on TF-IDF and TD-IDD, so as to combine the computational sim-plicity and accurate multi-class classification of the random forest with the data-driven discriminative power of the TF-IDF/TD-IDD methods. The proposed random forest cluster-ing with text-retrieval methods significantly outperforms two state-of-the-art methods on the dry-run set and the full set of the TRECVID MED 2010 dataset.
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Papers by Robert Mertens