2 resultados para automatic music analysis
em Duke University
Resumo:
Contrary Voices examines composer Hanns Eisler’s settings of nineteenth-century poetry under changing political pressures from 1925 to 1962. The poets’ ideologically fraught reception histories, both under Nazism and in East Germany, led Eisler to intervene in this reception and voice dissent by radically fragmenting the texts. His musical settings both absorb and disturb the charisma of nineteenth-century sound materials, through formal parody, dissonance, and interruption. Eisler’s montage-like work foregrounds the difficult position of a modernist artist speaking both to and against political demands placed on art. Often the very charisma the composer seeks to expose for its power to sway the body politic exerts a force of its own. At the same time, his text-settings resist ideological rigidity in their polyphonic play. A dialogic approach to musical adaptation shows that, as Eisler seeks to resignify Heine’s problematic status in the Weimar Republic, Hölderlin’s appropriation under Nazism, and Goethe’s status as a nationalist symbol in the nascent German Democratic Republic, his music invests these poetic voices with surprising fragility and multivalence. It also destabilizes received gender tropes, in the masculine vulnerability of Eisler’s Heine choruses from 1925 and in the androgynous voices of his 1940s Hölderlin exile songs and later Goethe settings. Cross-reading the texts after hearing such musical treatment illuminates faultlines and complexities less obvious in text-only analysis. Ultimately Eisler’s music translates canonical material into a form as paradoxically faithful as it is violently fragmented.
Resumo:
Knowledge-based radiation treatment is an emerging concept in radiotherapy. It
mainly refers to the technique that can guide or automate treatment planning in
clinic by learning from prior knowledge. Dierent models are developed to realize
it, one of which is proposed by Yuan et al. at Duke for lung IMRT planning. This
model can automatically determine both beam conguration and optimization ob-
jectives with non-coplanar beams based on patient-specic anatomical information.
Although plans automatically generated by this model demonstrate equivalent or
better dosimetric quality compared to clinical approved plans, its validity and gener-
ality are limited due to the empirical assignment to a coecient called angle spread
constraint dened in the beam eciency index used for beam ranking. To eliminate
these limitations, a systematic study on this coecient is needed to acquire evidences
for its optimal value.
To achieve this purpose, eleven lung cancer patients with complex tumor shape
with non-coplanar beams adopted in clinical approved plans were retrospectively
studied in the frame of the automatic lung IMRT treatment algorithm. The primary
and boost plans used in three patients were treated as dierent cases due to the
dierent target size and shape. A total of 14 lung cases, thus, were re-planned using
the knowledge-based automatic lung IMRT planning algorithm by varying angle
spread constraint from 0 to 1 with increment of 0.2. A modied beam angle eciency
index used for navigate the beam selection was adopted. Great eorts were made to assure the quality of plans associated to every angle spread constraint as good
as possible. Important dosimetric parameters for PTV and OARs, quantitatively
re
ecting the plan quality, were extracted from the DVHs and analyzed as a function
of angle spread constraint for each case. Comparisons of these parameters between
clinical plans and model-based plans were evaluated by two-sampled Students t-tests,
and regression analysis on a composite index built on the percentage errors between
dosimetric parameters in the model-based plans and those in the clinical plans as a
function of angle spread constraint was performed.
Results show that model-based plans generally have equivalent or better quality
than clinical approved plans, qualitatively and quantitatively. All dosimetric param-
eters except those for lungs in the automatically generated plans are statistically
better or comparable to those in the clinical plans. On average, more than 15% re-
duction on conformity index and homogeneity index for PTV and V40, V60 for heart
while an 8% and 3% increase on V5, V20 for lungs, respectively, are observed. The
intra-plan comparison among model-based plans demonstrates that plan quality does
not change much with angle spread constraint larger than 0.4. Further examination
on the variation curve of the composite index as a function of angle spread constraint
shows that 0.6 is the optimal value that can result in statistically the best achievable
plans.