112,426 research outputs found
SIMO DC-DC Converter for Automotive Audio Amplifier
No full textModern auto industry is ubiquitously deploying electronic systems for several applications like control, infotainment and security among others in the vehicles. Automotive infotainment is a key segment for the growth of automotive electronics as the vehicles, both light and heavy, require radio, video, navigation-assistance and telematics systems for both entertainment and networking.
Like any battery-operated systems, the automotive infotainment systems are required to provide high efficiency. One major constituent of in-vehicle infotainment being the radio, improving the overall efficiency of a car radio system is emphasized by the industry. In the state-of-the-art, the automotive audio amplifiers severely lack efficiency offering <40% in the mute condition. This research targets to improve the overall efficiency of an audio amplifier in a car radio by power supplying efficiently.
A Single Inductor Multiple Output dc-dc converter is explored as a supply voltage generator for an automotive audio amplifier in a car radio. The presence of line and load fluctuations, together with wide range of operating temperatures, in the automotive environment pose major challenge to the voltage regulation. A systematic feasibility study and analysis of specifications brought out the equivalence between the target SIMO converter and a non-inverting buck-boost SISO converter. Based on the equivalence, equilibrium and small signal models for the SIMO converter are developed. A voltage-mode, error-based controller is designed to control the dynamics of the converter. A novel power switching stage is conceived to generate the supplies required in a multi-channel class-D power amplifier. The switch
configuration is critical due the absence of a well-defined reference to one of the regulated outputs and the effect of package parasitics at high switching frequencies. The converter is charged synchronously and discharged quasi-synchronously to the loads. The switches are configured and driven optimally based on extensive simulations in the presence of package models to suppress the switching noise. In order to reduce the EM interference in the AM band of interest, the SIMO converter is switched at permissible high frequencies based on the EMI mask.
The automotive-class SIMO dc-dc converter is designed and integrated with a state-of-the-art class-D audio amplifier using 110nm BCD process technology offered by STMicroelectronics. The SIMO converter provides a battery tracking boost and a ground referred buck outputs for driving the class-D power stage. A unique feature of the converter is the generation of a floating voltage across half battery to supply the DSP core of the amplifier. The converter starts-up as boost converter alone followed entering boost-assisted SIMO converter mode. The active area occupied is 2.5mm2. The switching frequency is 2-2.4MHz. The converter has a load capability to drive up to 4 channels of a class-D power stage with peak efficiency of 86% and peak output power of 2.8W. The ripple voltage on the regulated outputs is below 25mV. The SIMO converter is able to sustain the automotive battery crank and dump conditions across the battery variation range of 4.5-27V. A line regulation of 6.3-16.2mV/V and a load regulation of 0.16mV/mA are provided by the SIMO converter. In the presence of wide range of battery variations, the SIMO converter incorporates all the necessary protections circuits and under/over voltage interrupts through I2C communication.Modern auto industry is ubiquitously deploying electronic systems for several applications like control, infotainment and security among others in the vehicles. Automotive infotainment is a key segment for the growth of automotive electronics as the vehicles, both light and heavy, require radio, video, navigation-assistance and telematics systems for both entertainment and networking.
Like any battery-operated systems, the automotive infotainment systems are required to provide high efficiency. One major constituent of in-vehicle infotainment being the radio, improving the overall efficiency of a car radio system is emphasized by the industry. In the state-of-the-art, the automotive audio amplifiers severely lack efficiency offering <40% in the mute condition. This research targets to improve the overall efficiency of an audio amplifier in a car radio by power supplying efficiently.
A Single Inductor Multiple Output dc-dc converter is explored as a supply voltage generator for an automotive audio amplifier in a car radio. The presence of line and load fluctuations, together with wide range of operating temperatures, in the automotive environment pose major challenge to the voltage regulation. A systematic feasibility study and analysis of specifications brought out the equivalence between the target SIMO converter and a non-inverting buck-boost SISO converter. Based on the equivalence, equilibrium and small signal models for the SIMO converter are developed. A voltage-mode, error-based controller is designed to control the dynamics of the converter. A novel power switching stage is conceived to generate the supplies required in a multi-channel class-D power amplifier. The switch
configuration is critical due the absence of a well-defined reference to one of the regulated outputs and the effect of package parasitics at high switching frequencies. The converter is charged synchronously and discharged quasi-synchronously to the loads. The switches are configured and driven optimally based on extensive simulations in the presence of package models to suppress the switching noise. In order to reduce the EM interference in the AM band of interest, the SIMO converter is switched at permissible high frequencies based on the EMI mask.
The automotive-class SIMO dc-dc converter is designed and integrated with a state-of-the-art class-D audio amplifier using 110nm BCD process technology offered by STMicroelectronics. The SIMO converter provides a battery tracking boost and a ground referred buck outputs for driving the class-D power stage. A unique feature of the converter is the generation of a floating voltage across half battery to supply the DSP core of the amplifier. The converter starts-up as boost converter alone followed entering boost-assisted SIMO converter mode. The active area occupied is 2.5mm2. The switching frequency is 2-2.4MHz. The converter has a load capability to drive up to 4 channels of a class-D power stage with peak efficiency of 86% and peak output power of 2.8W. The ripple voltage on the regulated outputs is below 25mV. The SIMO converter is able to sustain the automotive battery crank and dump conditions across the battery variation range of 4.5-27V. A line regulation of 6.3-16.2mV/V and a load regulation of 0.16mV/mA are provided by the SIMO converter. In the presence of wide range of battery variations, the SIMO converter incorporates all the necessary protections circuits and under/over voltage interrupts through I2C communication
author-bios-SRD-19-0063.R1 – Supplemental material for The Network Structure of Police Misconduct
No full textSupplemental material, author-bios-SRD-19-0063.R1 for The Network Structure of Police Misconduct by George Wood, Daria Roithmayr and Andrew V. Papachristos in Socius</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
No full text“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Intrasellar tuberculoma presenting as pituitary apoplexy
No full textThe combination of apoplectic symptoms and a sellar mass most often points to a diagnosis of a pituitary adenoma. Sellar tuberculomas are not considered as a cause of 'pituitary apoplexy' and there has been no radiological documentation of haemorrhage associated with them. We report a 27 years old man who presented with 3 previous episodes of pituitary apoplexy. CT scan showed evidence of a sellar mass with haemorrhage. Transsphenoidal biopsy of the intrasellar mass was reported as 'tuberculoma'. The patient had marked reduction in the size of the lesion following antituberculous therapy with no recurrence of symptoms. Intrasellar tuberculomas must be considered as one of the differential diagnosis when patients present with a pituitary apoplexy
Využití sociálních médií v B2B prodeji
No full textTato diplomová práce se zabývá tím, jak mohou B2B obchodníci využívat sociální média v prodeji. Na základě systematické rešerše literatury, autor zjistil, že akademici, zkoumající danou problematiku, navrhují další výzkum, a to: v kterých konkrétních krocích se dají využít sociální média v prodeji (Salo, 2017). Autor se na základě toho rozhodl zjistit, jaké sociální sítě, různé technologie a pluginy se dají využít v B2B prodeji - tzv. social sellingu. Social selling se v této práci týká primárně procesu akvizice a okrajově péčí o stávající zákazníky. Autor si vybral kvalitativní průzkum pomocí 10 hloubkových polo-strukturovaných rozhovorů, aby odhalil jak, která sociální média to jsou, tak i motivaci prodejců, proč tato média používat/nepoužívat. Aby autor dodržel správnost vyhodnocení výsledků, data byla analyzována pomocí Tématické analýzy, která v této studii vykrystalizovala 2 hlavní strategické přístupy v social sellingu. Tyto přístupy (tzv. Push a Pull strategie) obsahují praktické příklady a konkrétní aktivity, které mohou prodejci využívat v každodenní praxi. Tyto výsledky jsou prezentovány s důrazem na praktičnost a jednoduchost implementace. Tvoří proto hlavní přínos autorovo výzkumu. V poslední části autor zmiňuje výzvy a manažerská doporučení, které mohou obchodníci využít v každodenním pracovním životě.This diploma thesis focuses on social media usage in B2B sales. Based on the systematic literature review conducted by the author, he has found out that recent researchers (Salo, 2017) suggest further research in the area of how and in which sales phase should various social networking sites, technologies and plugins used. To further fill this research gap, author decided to identify these social media and their usage among B2B salespeople in the so-called social selling process. The social selling process in this thesis applies mainly to acquiring new prospects and tangentially to taking care of existing clients (follow-up step). Author has chosen a qualitative research method via conducting 10 in-depth semi-structured interviews to reveal these instruments as well as motivation of a sales person on why to use social media in the selling process. The collected data was analyzed using Thematic analysis to ensure the right procedure and to identify main themes which crystalized into 2 main strategic approaches in social selling. These approaches (Push and Pull) include practical examples of concrete activities which sales people can use in their daily jobs and are presented with focus on practicality and ease of implementation. These also form the main contribution of author`s research. In the last part, author mentions challenges in social selling and recommended managerial implications for salesforce
TeX v jednoduchém unixovém prostředí
No full textsummary:Při ladění TeXového dokumentu potřebujeme mnohokrát opakovaně pouštět TeX, podívat se, jak dopadl výsledek v prohlížeči DVI nebo PDF souboru, mrknout na výpis TeXu na terminálu, podívat se případně do logu a celou činnost opakovat. V tomto článku je ukázáno, jak tuto práci dělá autor článku. Proces "editor-TeX-kuk" je zde podporován jednoduchými unixovými nástroji: bashovým skriptem texloop, který si autor pro tyto účely vytvořil, dále terminálem Xterm a jednoduchým editorem, který umí navázat na klávesovou zkratku spuštění příkazu v systému. Čtenář se zde může inspirovat a přizpůsobit tyto nástroje svým vlastním potřebám. V článku je popsána funkce skriptu texloop, dále je neformálně rozveden dlouholetý vývoj autorova vztahu k textovým editorům a konečně je zde uvedena konfigurace terminálu Xterm, aby vyhovoval českému prostředí jak v kódování ISO-8859-2, tak v kódování UTF-8. Pro kódování UTF-8 si v závěru článku vygenerujeme TeXový formát csplain.summary:By debugging a TeX document it is necessary many times repeatedly to run TeX, to look for the result in DVI or PDF file, to gander the TeX output on the terminal, or eventually to have a look in the log-file, and all that action to repeat. In the paper it is show, how this work is made by author. The process '‘'editor-TeX-look' is supported by simple Unix tools: bash script texloop, created by author for these purposes, Xterm terminal and a simple editor, which is able to link to the shortcut key the activation of a system command. The reader could be inspired with the solution and to adapt these tools to his/her own needs. In the paper the function of the texloop script is described, and further the longstanding evolution of the author's relation to text editors is informal elaborated and finally a configuration of Xterm terminal, suitable for the czech environment with both ISO-8859-2 and UTF-8 encoding is introduced. For UTF-8 encoding the TeX format csplain is generated at the end of the paper
High cervical and lumbar canal stenosis of varied etiology: a case report
No full textDevelopmental stenosis without any significant spondylotic changes frequently occurs at C3 vertebra or below, and typically extends to C6-C7. However, high cervical focal canal stenosis is unusual. A case of cervical canal segmental stenosis at C2-3 level in addition to a developmental stenosis of the lumbar region, in a 45 year old male, has been presented in this article. The dynamics of the spinal canal in relation to the likely pathology of such conditions are reviewed. We speculate that focal segmental stenosis in the high cervical region may be due to a possible premature fusion of the neurocentral synchondrosis of the cartilage, or due to an abnormal rotary biomechanics which can result in facetal hypertrophy
High cervical and lumbar canal stenosis of varied etiology: a case report
No full textDevelopmental stenosis without any significant spondylotic changes frequently occurs at C3 vertebra or below, and typically extends to C6-C7. However, high cervical focal canal stenosis is unusual. A case of cervical canal segmental stenosis at C2-3 level in addition to a developmental stenosis of the lumbar region, in a 45 year old male, has been presented in this article. The dynamics of the spinal canal in relation to the likely pathology of such conditions are reviewed. We speculate that focal segmental stenosis in the high cervical region may be due to a possible premature fusion of the neurocentral synchondrosis of the cartilage, or due to an abnormal rotary biomechanics which can result in facetal hypertrophy
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