A Cost-effective Shuffling Method against DDoS Attacks using Moving Target Defense

Moving Target Defense (MTD) has emerged as a newcomer into the asymmetric field of attack and defense, and shuffling-based MTD has been regarded as one of the most effective ways to mitigate DDoS attacks. However, previous work does not acknowledge that frequent shuffles would significantly intensify the overhead. MTD requires a quantitative measure to compare the cost and effectiveness of available adaptations and explore the best trade-off between them. In this paper, therefore, we propose a new cost-effective shuffling method against DDoS attacks using MTD. By exploiting Multi-Objective Markov Decision Processes to model the interaction between the attacker and the defender, and designing a cost-effective shuffling algorithm, we study the best trade-off between the effectiveness and cost of shuffling in a given shuffling scenario. Finally, simulation and experimentation on an experimental software defined network (SDN) indicate that our approach imposes an acceptable shuffling overload and is effective in mitigating DDoS attacks

Multi-level Fusion of Wav2vec 2.0 and BERT for Multimodal Emotion Recognition

The research and applications of multimodal emotion recognition have become increasingly popular recently. However, multimodal emotion recognition faces the challenge of lack of data. To solve this problem, we propose to use transfer learning which leverages state-of-the-art pre-trained models including wav2vec 2.0 and BERT for this task. Multi-level fusion approaches including coattention-based early fusion and late fusion with the models trained on both embeddings are explored. Also, a multi-granularity framework which extracts not only frame-level speech embeddings but also segment-level embeddings including phone, syllable and word-level speech embeddings is proposed to further boost the performance. By combining our coattention-based early fusion model and late fusion model with the multi-granularity feature extraction framework, we obtain result that outperforms best baseline approaches by 1.3% unweighted accuracy (UA) on the IEMOCAP dataset.Comment: Accepted to INTERSPEECH 202

Hans Christian Andersen HOUSE OF FAIRYTALES - Design Proposal Based On Experienceable Architectural Space

This master's thesis is based on Hans Christian Andersen House of Fairytales Ideas Competition which was held in the winter 2013/2014 in Odense, Denmark. The purpose of the competition was to find a design for a new Hans Christian Andersen House of Fairytales with a fairytale garden which should be a must-see attraction of international standing, where both architecture and content are clearly rooted in the fairytales and the history of the site. The competition has been used as practical framework of the thesis providing program and a defined site for examination. However, this thesis does not provide a competition entry, but rather shifts the focus on the design of experienceable architectural space. The thesis consists of two main parts, background research related to the competition contents and the design proposal. Background research is divided into three chapters: background and introduction, site studies and the objective of the design, which give basic information about the author, the city and the site as well as analysis diagrams that demonstrating the previous studies. The design proposal is the main part of this thesis, aiming to test a solution for a building project which is in need of experienceable architectural space

Testing gene-environment interactions for rare and/or common variants in sequencing association studies.

The risk of many complex diseases is determined by a complex interplay of genetic and environmental factors. Advanced next generation sequencing technology makes identification of gene-environment (GE) interactions for both common and rare variants possible. However, most existing methods focus on testing the main effects of common and/or rare genetic variants. There are limited methods developed to test the effects of GE interactions for rare variants only or rare and common variants simultaneously. In this study, we develop novel approaches to test the effects of GE interactions of rare and/or common risk, and/or protective variants in sequencing association studies. We propose two approaches: 1) testing the effects of an optimally weighted combination of GE interactions for rare variants (TOW-GE); 2) testing the effects of a weighted combination of GE interactions for both rare and common variants (variable weight TOW-GE, VW-TOW-GE). Extensive simulation studies based on the Genetic Analysis Workshop 17 data show that the type I error rates of the proposed methods are well controlled. Compared to the existing interaction sequence kernel association test (ISKAT), TOW-GE is more powerful when there are GE interactions\u27 effects for rare risk and/or protective variants; VW-TOW-GE is more powerful when there are GE interactions\u27 effects for both rare and common risk and protective variants. Both TOW-GE and VW-TOW-GE are robust to the directions of effects of causal GE interactions. We demonstrate the applications of TOW-GE and VW-TOW-GE using an imputed data from the COPDGene Study

Breathing dissipative solitons in mode-locked fiber lasers

Dissipative solitons are self-localized coherent structures arising from the balance between energy supply and dissipation. Besides stationary dissipative solitons, there are dynamical ones exhibiting oscillatory behavior, known as breathing dissipative solitons. Substantial interest in breathing dissipative solitons is driven by both their fundamental importance in nonlinear science and their practical applications, such as in spectroscopy. Yet, the observation of breathers has been mainly restricted to microresonator platforms. Here, we generate breathers in a mode-locked fiber laser. They exist in the laser cavity under the pump threshold of stationary mode locking. Using fast detection, we are able to observe the temporal and spectral evolutions of the breathers in real time. Breathing soliton molecules are also observed. Breathers introduce a new regime of mode locking into ultrafast lasers. Our findings may contribute to the design of advanced laser sources and open up new possibilities of generating breathers in various dissipative systems

Striking nonlinear dynamics of mode-locked fibre lasers

We report on the real-time observation of various remarkable nonlinear phenomena in mode-locked fibre lasers. These include the build-up of dissipative solitons and soliton molecules, collision-induced soliton explosions, and the excitation and dynamics of breathing dissipative solitons and breather molecular complexes. Numerical simulations of the laser model support our experimental findings

Excitation of breather solitons in a mode-locked fibre laser

We report on the generation and study of breathing dissipative solitons in a mode-locked fibre laser. Breathers exist in the laser cavity under the pump threshold of stationary mode locking. For the first time to our knowledge, breathing soliton molecules are also observed. Numerical simulations of the laser model support our experimental findings

Breathing soliton dynamics in mode-locked fibre lasers

Dissipative solitons (DSs) in a nonlinear medium are localised coherent structures that result from the composite balance between conservative effects (nonlinearity and dispersion/diffraction) and dissipative ones (gain and loss). In addition to parameter-invariant stationary DSs, numerous nonlinear systems support breathing (pulsating) DSs, the energy of which is localised in space but oscillates in time, or vice versa. Such nonlinear waves are attracting considerable research interest in optics owing to their strong connection with the Fermi-Pasta-Ulam paradox, formation of rogue waves, turbulence and modulation instability phenomena. Apart from their fundamental importance in nonlinear science, breathing solitons are also attractive because of their potential for practical applications, such as in spectroscopy. Yet, the observation of these breathers has been mainly restricted to optical microresonator platforms. In this talk, I will report on the generation and study of breathing DSs in passively mode-locked fibre lasers. Breathing solitons feature periodic spectral and temporal evolutions over cavity round trips. Experimentally, we capture such fast dynamics spectrally and temporally in real time using time-stretch dispersive Fourier transform based single-shot spectral measurements and spatio-temporal intensity measurements. Remarkably, in the normal-dispersion regime of the laser cavity, breathers are excited in the laser under the pump threshold for stationary DS mode locking. For the first time in experiments with mode-locked fibre lasers, breathing soliton pair molecules are also generated in the cavity, which represent double-breather bound states with a close intra-pulse separation. The universal nature of the breather formation is indicated by our observation in a varying-length cavity, and further confirmed by numerical simulations of the laser model described by the complex cubic-quintic Ginzburg-Landau equation (CQGLE). When the laser has an average anomalous cavity dispersion, we observe a regime of operation where the laser oscillator generates multiple pulsating solitons with extreme ratios of maximal to minimal intensities in each period of pulsations. The soliton spectra also experience large periodic broadening and compression. These observations are, to the best of our knowledge, the first of their kind in a laser system. Breathers introduce a new regime of mode locking into ultrafast lasers. These findings not only carry importance from an application perspective, but also contribute more broadly to the fundamental understanding of dissipative soliton physics. Our observations further demonstrate that mode-locked fibre lasers are an ideal test bed for the study of complex nonlinear wave dynamics relevant to a large variety of physical systems. More generally, the complex CQGLE is the most common mathematical implementation of a dissipative system, describing many different nonlinear effects in physics, such as nonlinear waves, superconductivity, superfluidity, Bose-Einstein condensates, liquid crystals, plasmas, and numerous other phenomena. Therefore, it is reasonable to assume that the breathing DS dynamics found in this work are not limited to optical systems and will also be discovered in various other physical systems