Cyclone Codes

We introduce Cyclone codes which are rateless erasure resilient codes. They combine Pair codes with Luby Transform (LT) codes by computing a code symbol from a random set of data symbols using bitwise XOR and cyclic shift operations. The number of data symbols is chosen according to the Robust Soliton distribution. XOR and cyclic shift operations establish a unitary commutative ring if data symbols have a length of $p-1$ bits, for some prime number $p$. We consider the graph given by code symbols combining two data symbols. If $n/2$ such random pairs are given for $n$ data symbols, then a giant component appears, which can be resolved in linear time. We can extend Cyclone codes to data symbols of arbitrary even length, provided the Goldbach conjecture holds. Applying results for this giant component, it follows that Cyclone codes have the same encoding and decoding time complexity as LT codes, while the overhead is upper-bounded by those of LT codes. Simulations indicate that Cyclone codes significantly decreases the overhead of extra coding symbols

Bargaining in vertical relationships and suppliers' R&D profitability

This paper explores the effect of bargaining in vertical relationships on the profitability of suppliers’ R&D investments. Studies on the relationship between R&D and firm profitability mostly concentrate on the impact of horizontal market structure and neglect vertical interac-tions. Building on theoretical and empirical evidence about the effects of bargaining in vertical relationships, the crucial determinants of a supplier’s bargaining power are identified as the market position and the degree of concentration in the buyer portfolio. With respect to R&D profitability the latter is expected to diminish returns from R&D, while the former is expected to increase it. The hypotheses are tested using a sample of 472 German manufacturing firms. The empirical findings support all hypotheses and highlight the importance of tak-ing a supplier’s bargaining power into account when estimating R&D profitability. The estimated effects are considerable: for an average R&D performing supplier an increase of R&D intensity in 2010 by a percentage point would reduce profits by about 14 % in 2012 given the supplier depends completely on the largest three buyers and does hold an average market share. Contrastingly, a monopolist R&D performing supplier with average buyer concentra-tion would experience a profit increase by 10 % in 2012

Buyer power and suppliers' incentives to innovate

Buyer power is widely considered to decrease innovation incentives of suppliers. However, there is little empirical evidence for this statement. Our paper analyses how buyer power influences innovation incentives of upstream firms while taking into account the type of competition in the downstream market, namely price and technology. We explore this relationship empirically for a unique dataset containing 1,129 observations of German firms from manufacturing and service sectors including information on the economic dependency of firms from their buyers. Using a generalised Tobit model, we find a negative effect of buyer power on a supplier’s likelihood to start R&D activities. This negative effect is mitigated if the supplier faces powerful buyers operating under strong price competition. There is also weak evidence for a negative effect of buyer power on suppliers’ R&D intensity if the powerful buyer operates under strong technology competition

Innovationen, Anlageinvestitionen und immaterielle Investitionen

Dieser Beitrag untersucht die Beziehung verschiedener Konzepte von investiven Ausgaben in Unternehmen, ihre Verbindung zu Innovationen und die Faktoren, die Innovations- und Investitionsentscheidungen von Unternehmen beeinflussen. Neben dem traditionellen Investitionsbegriff, der sich überwiegend auf Sachanlageinvestitionen bezieht, werden die Konzepte der Innovationsausgaben und der immateriellen Investitionen vorgestellt. Auf Basis von Daten der deutschen Innovationserhebung wird abgeschätzt, welche Bedeutung diese unterschiedlichen Formen von Investitionen für einzelne Branchen haben und in welchem Umfang sich Innovationsausgaben und Investitionen überschneiden. Multivariate Analysen zu den Innovations- und Investitionsentscheidungen der Unternehmen zeigen, dass auf Seiten des Marktumfelds ein intensiver Technologiewettbewerb und kurze Produktzyklen Investitionen in neues Wissen, Humankapital und innovative Anlagen befördern, während ein starker Preiswettbewerb und niedrige Marktzutrittsbarrieren zu niedrigeren Investitionen in FuE beitragen

Towards Sentinel 2 based environmental contamination monitoring

Supporting environmental monitoring with remote sensing data considerably increases cost effectiveness and reliability of traditional, manual solutions. Additionally, by means of automation, it bears the potential to prevent contaminations or disasters through the availability of timely and spatially dense data. To this end, we investigate the possibility to monitor gas and oil pipelines of a storage cavern by using optical, multi spectral data from the Copernicus Sentinel 2 satellites. Due to a lack of known disasters/contaminations, we resort to a monitoring approach based on statistical outliers. First results demonstrate the general capability of our approach to detect contaminations and generate warnings

Directionality of THz emission from photoinduced gas plasmas

Forward and backward THz emission by ionizing two-color laser pulses in gas is investigated by means of a simple semi-analytical model based on Jefimenko's equation and rigorous Maxwell simulations in one and two dimensions. We find the emission in backward direction having a much smaller spectral bandwidth than in forward direction and explain this by interference effects. Forward THz radiation is generated predominantly at the ionization front and thus almost not affected by the opacity of the plasma, in excellent agreement with results obtained from a unidirectional pulse propagation model

A matrix representation of the CPM/PDD approach as a means for change impact analysis

Engineering changes occur in every life cycle phase of a product and in every step of the product development process. Today, the importance of engineering change management as a part of product development is constantly rising. Reasons besides the globalisation are that customers are interested in more customised products at the price of a mass product - a phenomenon [Eckert et al. 2003] call mass customisation -, failures in design and changes in customer wishes that can not entirely be prevented. According to Lindemann and Reichwald [Lindemann et. al. 1998] engineering change management consumes 30 to 50 %, sometimes even up to 70 % of the capacity in product development. According to Wildemann [Wildemann 2006] the average cost of one engineering change is about 1.400 EUR (working hours, scrapping and tooling cost, but no organisational cost). Multiplied with 425 changes per month in average, identified by Deubzer et. al. [Deubzer 2005], that results in 7.1 million EUR change cost per year for an average company in the automobile manufacturing industry. According to the rule of ten [VDI2247], engineering changes become more expensive and time consuming the later they occur in the product life. Hence, it is advantageous to perform changes as early as possible [Lindemann et al. 1998]. But on the other hand, today\u27;s markets and customer wishes change so quickly that a frontloading of engineering changes hinders the technological development of a company and endangers competitive advantages through innovation and customisation. Additionally, again according to Lindemann and Reichwald [Lindemann et. al. 1998], about 40 % of changes are recognised only after the completion of the production tools. That is supported by Wildemann [Wildemann 2006] who states that 50 % of the design-related changes happen in the preseries and series phase of the product development process. Approaches like Design for Changeability help to reduce change cost but even can not foresee all possible changes. Therefore, (engineering) change management is still an important task in product development. Thereof, especially the area of change impact analysis is the most significant part

Innovative lightweight aircraft design : a student competition

Education in engineering design is a challenging task. On the one hand the students have to get a broad theoretical basis and engineering expertise, on the other hand they have to learn how to apply their knowledge and how to face real technical problems [Pulko, 2004]. Since time in University is limited (in Germany a engineering degree at university level takes about 5 years to complete) often an emphasis is put on a sound theoretical education at the expense of practical experience. This paper presents a student competition between four German universities, which provides a practical team-work project for engineering (design) students that nearly spans the whole life-cycle from brainstorming for product ideas to manufacturing and usage of the product. The development task is an aircraft or flight device totally made of steel. Aim of the project is to apply the theoretical knowledge at a practical task