44 research outputs found
Anwendung von maschinellem Lernen in der optischen NachrichtenĂŒbertragungstechnik
Aufgrund des zunehmenden Datenverkehrs wird erwartet, dass die optischen Netze zukĂŒnftig mit höheren SystemkapazitĂ€ten betrieben werden. Dazu wird bspw. die kohĂ€rente Ăbertragung eingesetzt, bei der das Modulationsformat erhöht werden kann, erforder jedoch ein gröĂeres SNR. Um dies zu erreichen, wird die optische Signalleistung erhöht, wodurch die DatenĂŒbertragung durch die nichtlinearen BeeintrĂ€chtigungen gestört wird. Der Schwerpunkt dieser Arbeit liegt auf der Entwicklung von Modellen des maschinellen Lernens, die auf diese nichtlineare Signalverschlechterung reagieren. Es wird die Support-Vector-Machine (SVM) implementiert und als klassifizierende Entscheidungsmaschine verwendet. Die Ergebnisse zeigen, dass die SVM eine verbesserte Kompensation sowohl der nichtlinearen Fasereffekte als auch der Verzerrungen der optischen Systemkomponenten ermöglicht. Das Prinzip von EONs bietet eine Technologie zur effizienten Nutzung der verfĂŒgbaren Ressourcen, die von der optischen Faser bereitgestellt werden. Ein SchlĂŒsselelement der Technologie ist der bandbreitenvariable Transponder, der bspw. die Anpassung des Modulationsformats oder des Codierungsschemas an die aktuellen Verbindungsbedingungen ermöglicht. Um eine optimale Ressourcenauslastung zu gewĂ€hrleisten wird der Einsatz von Algorithmen des Reinforcement Learnings untersucht. Die Ergebnisse zeigen, dass der RL-Algorithmus in der Lage ist, sich an unbekannte Link-Bedingungen anzupassen, wĂ€hrend vergleichbare heuristische AnsĂ€tze wie der genetische Algorithmus fĂŒr jedes Szenario neu trainiert werden mĂŒssen
Exact Thermodynamics and Transport in the Classical Sine-Gordon Model
We revisit the exact thermodynamic description of the classical sine-Gordon
field theory, a notorious integrable model. We found that existing results in
the literature based on the soliton-gas picture did not correctly take into
account light, but extended, solitons and thus led to incorrect results. This
issue is regularized upon requantization: we derive the correct thermodynamics
by taking the semiclassical limit of the quantum model. Our results are then
extended to transport settings by means of Generalized Hydrodynamics.Comment: 33 pages, 4 figure
Mitigation of Nonlinear Impairments by Using Support Vector Machine and Nonlinear Volterra Equalizer
A support vector machine (SVM) based detection is applied to different equalization
schemes for a data center interconnect link using coherent 64 GBd 64-QAM over 100 km standard
single mode ïŹber (SSMF). Without any prior knowledge or heuristic assumptions, the SVM is able
to learn and capture the transmission characteristics from only a short training data set. We show
that, with the use of suitable kernel functions, the SVM can create nonlinear decision thresholds
and reduce the errors caused by nonlinear phase noise (NLPN), laser phase noise, I/Q imbalances
and so forth. In order to apply the SVM to 64-QAM we introduce a binary coding SVM, which
provides a binary multiclass classiïŹcation with reduced complexity. We investigate the performance
of this SVM and show how it can improve the bit-error rate (BER) of the entire system. After
100 km the ïŹber-induced nonlinear penalty is reduced by 2 dB at a BER of 3.7 Ă 10
â3
. Furthermore,
we apply a nonlinear Volterra equalizer (NLVE), which is based on the nonlinear Volterra theory,
as another method for mitigating nonlinear effects. The combination of SVM and NLVE reduces
the large computational complexity of the NLVE and allows more accurate compensation of nonlinear
transmission impairments
Tofacitinib Loaded Squalenyl Nanoparticles for Targeted Follicular Delivery in Inflammatory Skin Diseases
Tofacitinib (TFB), a Janus kinase inhibitor, has shown excellent success off-label in treating various dermatological diseases, especially alopecia areata (AA). However, TFBâs safe and targeted delivery into hair follicles (HFs) is highly desirable due to its systemic adverse effects. Nanoparticles (NPs) can enhance targeted follicular drug delivery and minimize interfollicular permeation and thereby reduce systemic drug exposure. In this study, we report a facile method to assemble the stable and uniform 240 nm TFB loaded squalenyl derivative (SqD) nanoparticles (TFB SqD NPs) in aqueous solution, which allowed an excellent loading capacity (LC) of 20%. The SqD NPs showed an enhanced TFB delivery into HFs compared to the aqueous formulations of plain drug in an ex vivo pig ear model. Furthermore, the therapeutic efficacy of the TFB SqD NPs was studied in a mouse model of allergic dermatitis by ear swelling reduction and compared to TFB dissolved in a non-aqueous mixture of acetone and DMSO (7:1 v/v). Whereas such formulation would not be acceptable for use in the clinic, the TFB SqD NPs dispersed in water illustrated a better reduction in inflammatory effects than plain TFBâs aqueous formulation, implying both encouraging good in vivo efficacy and safety. These findings support the potential of TFB SqD NPs for developing a long-term topical therapy of AA
Coherence onset in PT-symmetric organic microcavities: towards directional propagation of light
For the investigation of non-Hermitian effects and physics under parity-time (PT) symmetry, photonic systems are ideal model systems for both experimental and theoretical research. We investigate a fundamental building block of a potential photonic device, consisting of coupled organic microcavities. The coupled system contains cavities with gain and loss and respects parity-time symmetry, leading to non-Hermitian terms in the corresponding Hamiltonian. Experimentally, two coupled cavities are realized and driven optically using pulsed laser excitation up to the lasing regime. We show that above the lasing threshold, when coherence evolves, the coupled-cavity system starts to operate asymmetrically, generating more light on one side of the device, being characteristic of non-Hermitian PT-symmetric systems. Calculations and simulations on a SuâSchriefferâHeeger (SSH) chain composed of these PT-symmetric unit cells show the emergence of non-trivial topological features
A New PqsR Inverse Agonist Potentiates Tobramycin Efficacy to Eradicate Pseudomonas aeruginosa Biofilms
Pseudomonas aeruginosa (PA) infections can be notoriously difficult to treat and are often accompanied by the development of antimicrobial resistance (AMR). Quorum sensing inhibitors (QSI) acting on PqsR (MvfR) â a crucial transcriptional regulator serving major functions in PA virulence â can enhance antibiotic efficacy and eventually prevent the AMR. An integrated drug discovery campaign including design, medicinal chemistry-driven hit-to-lead optimization and in-depth biological profiling of a new QSI generation is reported. The QSI possess excellent activity in inhibiting pyocyanin production and PqsR reporter-gene with IC50 values as low as 200 and 11Â Ă 10â9 m, respectively. Drug metabolism and pharmacokinetics (DMPK) as well as safety pharmacology studies especially highlight the promising translational properties of the lead QSI for pulmonary applications. Moreover, target engagement of the lead QSI is shown in a PA mucoid lung infection mouse model. Beyond that, a significant synergistic effect of a QSI-tobramycin (Tob) combination against PA biofilms using a tailor-made squalene-derived nanoparticle (NP) formulation, which enhance the minimum biofilm eradicating concentration (MBEC) of Tob more than 32-fold is demonstrated. The novel lead QSI and the accompanying NP formulation highlight the potential of adjunctive pathoblocker-mediated therapy against PA infections opening up avenues for preclinical development
Berufliche StabilitÀts- und FlexibilitÀtsorientierungen in Ostdeutschland: Ergebnisse eines Forschungspraktikums
Das im folgenden vorgestellte Projekt StabilitĂ€ts- und FlexibilitĂ€tsorientierungen in ostdeutschen LebensverlĂ€ufen wurde am Institut fĂŒr Soziologie der UniversitĂ€t Leipzig im Rahmen eines Lehrpraktikums durchgefĂŒhrt. In dem Projekt wurden berufliche StabilitĂ€ts- und FlexibilitĂ€tsorientierungen ostdeutscher BeschĂ€ftigter vor dem Hintergrund individueller Ressourcen und Gelegenheitsstrukturen untersucht. Anhand von 68 biographischen Interviews Ă€lterer und jĂŒngerer Kohorten sollte gezeigt werden, in welchem MaĂe individuelle Merkmale sowie familiĂ€re, arbeitsmarktliche, sozialpolitische und betriebliche Gelegenheitsstrukturen die individuellen Handlungsorientierungen beeinflussen. Vor dem Hintergrund der \"Entstandardisierung\" von Lebenslaufmustern und der \"Flexibilisierung\" von ErwerbsverlĂ€ufen wurde dabei nach den Ursachen und VerĂ€nderungen kohortenspezifischer Unterscheidungen berufsbiographischer EntwĂŒrfe gefragt.:Vorbemerkung; StabilitĂ€t und FlexibilitĂ€t im Lebensverlauf; Analytisches Modell und methodisches Vorgehen; Ergebnisse; BewĂ€ltigungsstrategien â Eine Zusammenfassung; Literatur, Anhan
Exact thermodynamics and transport in the classical Sine-Gordon model
We revisit the exact thermodynamic description of the classical sine-Gordon field theory, a well-known integrable model. We found that existing results in the literature based on the soliton-gas picture did not correctly take into account light, but extended, solitons and thus led to incorrect results. This issue is regularized upon requantization: we derive the correct thermodynamics by taking the semiclassical limit of the quantum model. Our results are then extended to transport settings by means of Generalized Hydrodynamics