North Atlantic Current in model and observations: Transport variability, flow paths and hydrography

The North Atlantic Current (NAC) is subject to variability on multiannual to decadal time scales, influencing the transport of volume, heat and freshwater from the subtropical to the eastern subpolar North Atlantic (NA). Current observational time series are either too short or too episodic to comprehensively study the processes involved, therefore models are used to complement the observations. For this study, moored and ship-based observations from three sections along the NAC pathway, satellite altimetry data and 1/20 degree hindcast VIKING20 model configuration (1960-2008) output are used. They are investigated and compared to describe hydrography, flow field and transport time series. The flow into and out of the NA is monitored at 47 degree N, the flow from the western into the eastern basin of the NA is captured by a section at the western flank of the Mid-Atlantic Ridge (MAR), and the distribution in the eastern basin of the NA is observed at the OVIDE line. These three sections thus provide an extensive picture of the flow

Competition among High-Frequency Traders, and Market Quality

We study empirically how competition among high-frequency traders (HFTs) affects their trading behavior and market quality. Our analysis exploits a unique dataset, which allows us to compare environments with and without high-frequency competition, and contains an exogenous event - a tick size reform - which we use to disentangle the effects of the rising share of high-frequency trading in the market from the effects of high-frequency competition. We find that when HFTs compete, their speculative trading increases. As a result, market liquidity deteriorates and short-term volatility rises. Our findings hold for a variety of market quality and high-frequency trading behavior measures

Competition between high-frequency traders, and market quality

This is the first empirical evidence on the competition between high-frequency traders (HFTs) and its influence on market quality. We exploit the first entries of international HFTs into the Swedish equity market in 2009 and conduct a difference-in-differences analysis using trade-by-trade data. To further identify the effect, we use the Federation of European Securities Exchanges (FESE) tick size harmonization as an exogenous event that caused HFTs to start trading in stocks. When HFTs compete for trades their liquidity consumption increases. As a result, liquidity deteriorates significantly and short-term volatility rises

Von persönlicher Schutzbekleidung zum mobilen Schutzassistenzsystem

Miniaturized and embedded computers open new prospects for Personal Protective Equipment (PPE). PPE will recognize context and react on environmental hazards in an autonomous way in the future. Networked components may predict dangerous situations. These complex systems demand a new participatory design process because the new protective functions have to adjust between user and automated technique for practical use. This PhD thesis deals with the user-oriented development process for these new ambient assisted protection systems. A specific workflow follows the process-oriented and networked character of the new mobile protection system. In addition designated design attributes motivate the need of clothing related solutions

Competition between high-frequency traders, and market quality

This is the first empirical evidence on the competition between high-frequency traders (HFTs) and its influence on market quality. We exploit the first entries of international HFTs into the Swedish equity market in 2009 and conduct a difference-in-differences analysis using trade-by-trade data. To further identify the effect, we use the Federation of European Securities Exchanges (FESE) tick size harmonization as an exogenous event that caused HFTs to start trading in stocks. When HFTs compete for trades their liquidity consumption increases. As a result, liquidity deteriorates significantly and short-term volatility rises

Competition between high-frequency traders, and market quality

This is the first empirical evidence on the competition between high-frequency traders (HFTs) and its influence on market quality. We exploit the first entries of international HFTs into the Swedish equity market in 2009 and conduct a difference-in-differences analysis using trade-by-trade data. To further identify the effect, we use the Federation of European Securities Exchanges (FESE) tick size harmonization as an exogenous event that caused HFTs to start trading in stocks. When HFTs compete for trades their liquidity consumption increases. As a result, liquidity deteriorates significantly and short-term volatility rises

Competition among High-Frequency Traders, and Market Quality

We study empirically how competition among high-frequency traders (HFTs) affects their trading behavior and market quality. Our analysis exploits a unique dataset, which allows us to compare environments with and without high-frequency competition, and contains an exogenous event - a tick size reform - which we use to disentangle the effects of the rising share of high-frequency trading in the market from the effects of high-frequency competition. We find that when HFTs compete, their speculative trading increases. As a result, market liquidity deteriorates and short-term volatility rises. Our findings hold for a variety of market quality and high-frequency trading behavior measures

Possibilities and limits of virtual and augmented reality in the purchase decision process for clothing

This paper examines the influence of virtual and augmented reality on the purchasing decision-making process for clothing. The aim of the study is to gain well-founded insights into the possibilities and limitations of using virtual and augmented reality (VR and AR) techniques in that process. It can be shown that VR and AR applications as interactive systems can offer valuable support in the purchasing decision-making process. New chances and possibilities arise for future shopping in virtual or augmented realities, in which customers are supported in their decision-making. So far, the simulation of visual properties, the limited range of offered pieces, the lack of customer acceptance as well as high barriers to entry and expensive hardware solutions have weakened the full exploitation of potential

Flow paths and variability of the North Atlantic Current: A comparison of observations and a high-resolution model

The North Atlantic Current (NAC) is subject to variability on multiannual to decadal time scales, influencing the transport of volume, heat, and freshwater from the subtropical to the eastern subpolar North Atlantic (NA). Current observational time series are either too short or too episodic to study the processes involved. Here we compare the observed continuous NAC transport time series at the western flank of the Mid-Atlantic Ridge (MAR) and repeat hydrographic measurements at the OVIDE line in the eastern Atlantic with the NAC transport and circulation in the high-resolution (1/20°) ocean model configuration VIKING20 (1960–2008). The modeled baroclinic NAC transport relative to 3400 m (24.5 ± 7.1 Sv) at the MAR is only slightly lower than the observed baroclinic mean of 27.4 ± 4.7 Sv from 1993 to 2008, and extends further north by about 0.5°. In the eastern Atlantic, the western NAC (WNAC) carries the bulk of the transport in the model, while transport estimates based on hydrographic measurements from five repeated sections point to a preference for the eastern NAC (ENAC). The model is able to simulate the main features of the subpolar NA, providing confidence to use the model output to analyze the influence of the North Atlantic Oscillation (NAO). Model based velocity composites reveal an enhanced NAC transport across the MAR of up to 6.7 Sv during positive NAO phases. Most of that signal (5.4 Sv) is added to the ENAC transport, while the transport of the WNAC was independent of the NAO

Thermodynamic qualification of knitted spacer fabrics for use as insulation box insert in the context of refrigerated transport containers in the logistics sector

Temperature-sensitive products such as refrigerated and frozen goods pose particular challenges for logistics. Against the background of the mobility shift towards electric vehicles and the current challenges of temperature-stable transport in the field of pharmaceutical, esp. vaccine logistics in the context of the SARS-CoV-2 pandemic, new, energy-efficient vehicle equipment is needed to maintain cold chains. Known refrigeration concepts are designed to cool the entire cargo hold. In addition, the goods cannot be removed from the vehicle while maintaining the cold chain. An insulating effect of containers is typically achieved by using foamed polystyrene (Styrofoam). On the one hand, these structures have a very good insulating effect, but on the other hand, they cannot be reduced in volume during recirculation and are problematic with regard to recycling. The aim of the research presented here is therefore to develop a knitted box that is designed as a volume-reducible, rigid but foldable box. This can be used as a supplement to existing transport container systems and therefore can be inserted in the transport container. The knitted box performs as insulation when the transported goods are actively cooled inside the box, which is more sustainable and flexible than recent insulation solutions. Knitted fabrics, especially spacer fabrics, have advantageous thermo-physical properties for this application due to their structural design. In the course of a research project, various spacer fabrics were tested for their thermo-physical suitability as insulation materials. It was found that knitted predetermined folding lines represent an insulation gap. Based on this, a new structure was developed which, due to its structural design, compensates for cold or thermal bridges at vertices and edges of the box. The results show that the knitted corrugated structure insulates better than the knitted spacer fabrics with predetermined folding lines. A thermal imaging camera was used to identify critical points for heat transfer