255 research outputs found
IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica
No full text20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)The recent observation by the IceCube neutrino observatory of an astrophysical flux of neutrinos represents the "first light" in the nascent field of neutrino astronomy. The observed diffuse neutrino flux seems to suggest a much larger level of hadronic activity in the non-thermal universe than previously thought and suggests a rich discovery potential for a larger neutrino observatory. This document presents a vision for an substantial expansion of the current IceCube detector, IceCube-Gen2, including the aim of instrumenting a volume of clear glacial ice at the South Pole to deliver substantial increases in the astrophysical neutrino sample for all flavors. A detector of this size would have a rich physics program with the goal to resolve the sources of these astrophysical neutrinos, discover GZK neutrinos, and be a leading observatory in future multi-messenger astronomy programs
Grade subjektiver Sicherheit: Verarbeitung und Repräsentation
No full textCONTENTS
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1 ZUSAMMENFASSUNG
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4 ABSTRACT
..................................................................................................................
6 LIST OF ORIGINAL RESEARCH ARTICLES
............................................................. 7 1\. GENERAL
OVERVIEW
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8 a. Origins and current state of the experimental investigation of confidence
........... 9 b. Two types of confidence
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11 2\. THE MEASUREMENT OF CONFIDENCE
............................................................ 12 a. Implicit
measures
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12 b. Explicit measures
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14 3\. PROCESS MODELS OF CONFIDENCE
.............................................................. 14 4\.
CONFIDENCE AND THE BRAIN
.......................................................................... 16
a. Humans
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17 b. Animals
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18 5\. RESEARCH QUESTIONS
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19 6\. GENERAL METHODOLOGY
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20 a. Tasks and stimuli
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20 b. Variables controlled for (quantities held constant)
............................................. 21 c. Subject-specific stimulus
calibration
................................................................... 22 d.
Measures
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22 1\. Behavioral
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22 2\. Functional Magnetic Resonance Imaging
...................................................... 23 7\. STUDY SUMMARIES
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24 a. Study 1
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24 b. Study 2
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26 c. Study 3
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28 8\. GENERAL DISCUSSION
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30 a. Representation of confidence
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31 1\. Task-independence
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31 2\. Redundant representation of confidence
........................................................ 32 b. Confidence:
epistemic belief or metacognition?
................................................. 33 c. Asking for confidence
does not influence decisions ........................................... 34 d.
Second-stage processing of both confidence and choice
.................................. 36 e. Rating confidence does not require
implicit choice ............................................ 37 f. Are
confidence ratings decisions?
...................................................................... 37 g.
What is the purpose of computing confidence?
................................................. 39 h. Implication of task-
independent confidence for subjective probability ............... 39 j.
Implications of this dissertation for current process models of confidence and
choice
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40 k. Limitations and outlook
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41 9\. GENERAL CONCLUSION
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42 REFERENCES
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44 EIDESSTATTLICHE ERKLÄRUNG
........................................................................... 50
RESEARCH ARTICLES
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51Am I really sure? This is a question we ask ourselves practically every day.
But when you ask yourself how confident you are, do you ask yourself before or
after you make a choice? Most likely you have experienced both and in fact
there is good evidence for both pre- and postdecision confidence processing.
It remains unclear, however, whether and how these processes differ from each
other. More generally, it is an open question how exactly the processing of
confidence and choice relate to each other. Finally, it is an open question in
which format confidence is represented on the neural level. In the three
studies constituting this thesis, I address these issues of representation and
processing. In study one, by combining two perceptual decision tasks with
functional Magnetic Resonance Imaging (fMRI), I provide neural evidence for a
task-independent representation of degrees of subjective certainty (i.e., a
neural representation of subjective certainty prior to choice that remains
constant across tasks). The results indicate that confidence is represented in
an abstract format, i.e. independent of its referent." In study two, I use a
perceptual decision task to show that confidence in incorrect trials is higher
prior to choice than after choice. At the same time, confidence in correct
trials remains unaffected by variation of the response order. This indicates
that in contrast to pre decision confidence, post decision confidence is
informed by metacognitive error detection. While the former is based on
incoming evidence and best viewed as degree of epistemic belief, the latter
additionally draws on higher order metacognitive monitoring of the decision
process. Therefore, confidence understood as degree of epistemic belief prior
to choice is not associated with metacognition, while after choice it is." In
study three, I show second stage processing, i.e. continued processing after
the first response, of both confidence and choice. In addition, I show that
confidence and choice differ in their computational demands, as indicated by
longer response times in ratings than decisions. Finally, my results suggest
that confidence and choice processing are largely decoupled." Taken together,
the present thesis provides novel insights into the representational format of
confidence, a conceptual clarification of confidence as degree of belief and
an empirical dissociation from related concepts, such as metacognition.
Thereby, this thesis adds basic conditions to future theorizing about degrees
of belief.Bin ich mir wirklich sicher? Diese Frage stellen wir uns wohl täglich. Aber
wenn wir uns fragen, wie sicher wir uns sind, machen wir das bevor oder
nachdem wir uns entscheiden? Mit ziemlicher Sicherheit hat man schon beides
getan und tatsächlich gibt es empirische Evidenz für die Verarbeitung
subjektiver Sicherheit bevor und nachdem wir uns entscheiden. Bislang ist
jedoch unklar, ob, und wenn ja, wie, die entsprechenden Prozesse sich
voneinander unterscheiden. Darüber hinaus ist auch noch unbekannt, wie genau
sich die Berechnung subjektiver Sicherheit und der Entscheidungsprozess
zueinander verhalten. Ebenfalls unklar ist, in welchem Format subjektive
Sicherheit auf neuronaler Ebene repräsentiert ist. In den drei dieser Arbeit
zugrundeliegenden Studien untersuche ich diese Fragen zu Repräsentation und
Verarbeitung von Graden subjektiver Sicherheit. In Studie 1 habe ich zwei
perzeptuelle Entscheidungsaufgaben mit funktioneller Magnet Resonanz
Tomographie (fMRT) kombiniert und gezeigt, dass Grade subjektiver Sicherheit
auf neuronaler Ebene in aufgabenunabhängiger Weise repräsentiert sind. Das
heißt, ich habe eine neuronale Repräsentation subjektiver Sicherheit gefunden,
die über Aufgaben hinweg konstant ist. Dies deutet darauf hin, dass Grade
subjektiver Sicherheit in einem abstrakten Format repräsentiert sind, also
unabhängig von ihrem Gegenstand." In Studie 2 habe ich mit einer perzeptuellen
Entscheidungsaufgabe gezeigt, dass subjektive Sicherheit in Fehlertrials vor
Entscheidungen höher ist als nach Entscheidungen. Gleichzeitig bleibt aber
subjektive Sicherheit in korrekten Trials unberührt vom Zeitpunkt des
Ratings. Dies deutet darauf hin, dass im Gegensatz zu subjektiver Sicherheit
vor Entscheidungen, Sicherheit nach Entscheidungen zusätzlich auf
metakognitive Fehlerentdeckungsmechanismen zurückgreift. Somit weist
subjektive Sicherheit nach Entscheidungen ein metakognitives Element auf, was
für subjektive Sicherheit vor Entscheidungen nicht der Fall ist. In Studie 3
zeige ich, dass Verarbeitung auf einer zweiten Ebene, also nach Verarbeitung
der ersten Antwort (Sicherheitsrating oder Entscheidung), sowohl für
subjektive Sicherheit als auch für Entscheidungen stattfindet. Weiterhin
zeige ich, dass die Verarbeitung von subjektiver Sicherheit mehr Rechenaufwand
erfordert als die von Entscheidungen. Abschließend legen meine Ergebnisse
nahe, dass Sicherheits- und Entscheidungsverarbeitung weitgehend entkoppelt
sind. Insgesamt liefert die vorliegende Arbeit neuartige Einsichten in das
repräsentationale Format subjektiver Sicherheit, eine konzeptuelle Klärung von
subjektiver Sicherheit als Sicherheit in der persönlichen Einschätzung eines
Sachverhaltes und eine empirische Abgrenzung zu Nachbarkonzepten wie
Metakognition. Dadurch setzt sie Rahmenbedingungen für die weitere
Theorienbildung zu Graden subjektiver Sicherheit
“All humans are cast into battle:” Ephrem the Syrian’s Theology of Spiritual Struggle and Ascetic Heroism
No full textEphrem the Syrian (306–307 CE) is widely celebrated as one of the greatest Christian poets. Previous scholarship has shown that symbolic language is for him a matter of theological necessity. Symbols and metaphors are the idiom of Revelation—they must also be the idiom of theology, of human language about God. If this is true, the study of Ephrem’s use of metaphors should cast into relief theological patterns embedded in his poetry, patterns so subtle and unthematized that they can easily remain undetected (chap. 1).This dissertation examines one specific set of metaphors in the hymns (madrashe) and sermons (memre) of Ephrem: the images of warfare and athletic competition. Agonistic language, it appears, serves Ephrem primarily to describe the ascetic dimension of human existence. The struggle (aguna) into which all humans are cast is the birthright of human freedom, situated between good and evil. A fascinating pattern emerges from Ephrem’s construal of ascetic practices: even as he highlights human agency, he forestalls any potential lapse into voluntarism. Spiritual warfare and ascetic efforts, to Ephrem’s mind, are not a matter of the strong and the elite, but the domain of the weak (chap. 2).Bringing “aguna” as hermeneutical key to biblical stories, often in dialogue with rabbinic traditions, Ephrem highlights such aspects of the patriarchs’ struggles as are applicable to all Christians, showing the extraordinary nature of the seemingly inconspicuous (chaps. 3 and 4). The “Memra on Jonah and the Repentance of Nineveh,” read against the backdrop of ancient epic literature, reveals that Ephrem seeks to create a Christian ideal in which repentance, construed as a battle, is the epitome of heroism (chap. 5).These findings force us to reexamine our understanding of Ephrem as an ascetic author. He has been wrongly characterized as largely uninterested in the concerns of lay life. With his constant emphasis on the heroic nature of ordinary struggles and his insistence on the prominent place of the weak in Christ’s army, Ephrem should instead be seen as an early proponent of an ascetic spirituality for the lay.</p
Zum Problem des diagnostischen und therapeutischen Vorgehens im Rahmen des Hüftgelenkscreenings
No full textAnalysis of 802.11 OFDM in high multipath environments
No full textThe performance loss of 802.11 OFDM systems due to propagation delay spread has been analyzed as a function of OFDM parameters for a wide range of reverberation times. This analysis gives physical insight and solutions for the OFDM design to suppress the performance degradation
Performance degradation due to multipath noise for narrowband OFDM systems: channel-based analysis and experimental determination
No full textThe performance of OFDM systems over a multipath channel can strongly degrade due to the propagation delay spread. The distortion of the received signal over the fast Fourier transform window is referred to as multipath noise. This work aims to analytically determine the performance loss due to multipath noise as a function of OFDM and channel parameters for narrowband OFDM systems. First, it is investigated whether it is possible to describe the multipath noise, varying over different OFDM packets due to the temporal variation of the channel, by an effective noise factor F-delay, from which the loss factor is directly determined. Second, the theory of room electromagnetics is applied to develop a closed-form expression for F-delay as a function of the OFDM and reverberation parameters. This analytical method is validated with excellent agreement. Finally, the loss factor is determined for IEEE 802.11 based on channel measurements in two large conference rooms, providing values up to 19 dB for an 800 ns cyclic prefix length
Development of path loss model for 802.11n in large conference rooms
No full textIn this paper, a path loss (PL) model for 802.11n in large conference rooms is determined, based on PL measurements. The PL can be described accurately by a one-slope model with one standard deviation. PL exponents varying from 1.2 to 1.7 are found. Based on this PL model, the effect of frequency (2.4 vs 5 GHz), configuration (SISO vs MIMO (spatial diversity)), bandwidth (20 vs 40 MHz) and transmit power on number of access points, total power consumption and possible (physical) throughputs is investigated. According to the determined PL model, a higher range (by tuning the transmit power) requires less access points, as well as a lower total power consumption, due to a PL exponent lower than 2
Make and Sell or Buy of Web Services a Real Option Approach
No full textThe emergence of the web service market in the last years offers more and more the opportunity for companies to buy web services from external service providers as an alternative to develop them internally. Such considerations are well-known in IS literature and discussed in the context of IT outsourcing and make-orbuy decision making regarding IT applications. However, characteristics of web services like loose coupling or highly standardized interfaces open the door for a further opportunity to companies: If a company decides to internally develop a web service (make decision), it has additionally the right (but not the obligation) to sell it on the electronic web service market. The present paper examines how such a sell option can be modeled to enhance traditional make-or-buy approaches to a make-and-sell or buy approach for web services. To evaluate the sell option, we draw on real option analysis which is frequently used in valuating IT assets like IT applications. Furthermore, we apply our approach in a real world example of a financial service provider to demonstrate its applicability and practical benefits. By doing so we illustrate that the option to sell a web service may have considerable impact on traditional make-or-buy decisions
Ermittlung der Ursachen von Fehlbeurteilungen angeborener Hueftgelenksveraenderungen zur Operationalisierung optimaler Screeningstrategien
No full textSIGLEAvailable from TIB Hannover: RO 9717(1991,1) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman
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