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The binary asymmetric channel (BAC) is a model for the error characterization of multi-level cell (MLC) flash memories. This contribution presents a joint channel and source coding approach improving the reliability of MLC flash memories. The objective of the data compression algorithm is to reduce the amount of user data such that the redundancy of the error correction coding can be increased in order to improve the reliability of the data storage system. Moreover, data compression can be utilized to exploit the asymmetry of the channel to reduce the error probability. With MLC flash memories data compression has to be performed on block level considering short data blocks. We present a coding scheme suitable for blocks of 1 kilobyte of data.
This work proposes a lossless data compression algorithm for short data blocks. The proposed compression scheme combines a modified move-to-front algorithm with Huffman coding. This algorithm is applicable in storage systems where the data compression is performed on block level with short block sizes, in particular, in non-volatile memories. For block sizes in the range of 1(Formula presented.)kB, it provides a compression gain comparable to the Lempel–Ziv–Welch algorithm. Moreover, encoder and decoder architectures are proposed that have low memory requirements and provide fast data encoding and decoding.
One major realm of Condition Based Maintenance is finding features that reflect the current health state of the asset or component under observation. Most of the existing approaches are accompanied with high computational costs during the different feature processing phases making them infeasible in a real-world scenario. In this paper a feature generation method is evaluated compensating for two problems: (1) storing and handling large amounts of data and (2) computational complexity. Both aforementioned problems are existent e.g. when electromagnetic solenoids are artificially aged and health indicators have to be extracted or when multiple identical solenoids have to be monitored. To overcome those problems, Compressed Sensing (CS), a new research field that keeps constantly emerging into new applications, is employed. CS is a data compression technique allowing original signal reconstruction with far fewer samples than Shannon-Nyquist dictates, when some criteria are met. By applying this method to measured solenoid coil current, raw data vectors can be reduced to a way smaller set of samples that yet contain enough information for proper reconstruction. The obtained CS vector is also assumed to contain enough relevant information about solenoid degradation and faults, allowing CS samples to be used as input to fault detection or remaining useful life estimation routines. The paper gives some results demonstrating compression and reconstruction of coil current measurements and outlines the application of CS samples as condition monitoring data by determining deterioration and fault related features. Nevertheless, some unresolved issues regarding information loss during the compression stage, the design of the compression method itself and its influence on diagnostic/prognostic methods exist.
This work proposes a decoder implementation for high-rate generalized concatenated (GC) codes. The proposed codes are well suited for error correction in flash memories for high reliability data storage. The GC codes are constructed from inner extended binary Bose-Chaudhuri-Hocquenghem (BCH) codes and outer Reed-Solomon (RS) codes. The extended BCH codes enable high-rate GC codes. Moreover, the decoder can take advantage of soft information. For the first three levels of inner codes we propose an optional Chase soft decoder. In this work, the code construction is explained and a decoder architecture is presented. Furthermore, area and throughput results are discussed.
A flight-like absolute optical frequency reference based on iodine for laser systems at 1064 nm
(2017)
We present an absolute optical frequency reference based on precision spectroscopy of hyperfine transitions in molecular iodine 127I2 for laser systems operating at 1064 nm. A quasi-monolithic spectroscopy setup was developed, integrated, and tested with respect to potential deployment in space missions that require frequency stable laser systems. We report on environmental tests of the setup and its frequency stability and reproducibility before and after each test. Furthermore, we report on the first measurements of the frequency stability of the iodine reference with an unsaturated absorption cell which will greatly simplify its application in space missions. Our frequency reference fulfills the requirements on the frequency stability for planned space missions such as LISA or NGGM.
In several organizations, business workgroups autonomously implement information technology (IT) outside the purview of the IT department. Shadow IT, evolving as a type of workaround from nontransparent and unapproved end-user computing (EUC), is a term used to refer to this phenomenon, which challenges norms relative to IT controllability. This report describes shadow IT based on case studies of three companies and investigates its management. In 62% of cases, companies decided to reengineer detected instances or reallocate related subtasks to their IT department. Considerations of risks and transaction cost economics with regard to specificity, uncertainty, and scope explain these actions and the resulting coordination of IT responsibilities between the business workgroups and IT departments. This turns shadow IT into controlled business-managed IT activities and enhances EUC management. The results contribute to the governance of IT task responsibilities and provide a way to formalize the role of workarounds in business workgroups.
Observer-based self sensing for digital (on–off) single-coil solenoid valves is investigated. Self sensing refers to the case where merely the driving signals used to energize the actuator (voltage and coil current) are available to obtain estimates of both the position and velocity. A novel observer approach for estimating the position and velocity from the driving signals is presented, where the dynamics of the mechanical subsystem can be neglected in the model. Both the effect of eddy currents and saturation effects are taken into account in the observer model. Practical experimental results are shown and the new method is compared with a full-order sliding mode observer.
Sleep quality and in general, behavior in bed can be detected using a sleep state analysis. These results can help a subject to regulate sleep and recognize different sleeping disorders. In this work, a sensor grid for pressure and movement detection supporting sleep phase analysis is proposed. In comparison to the leading standard measuring system, which is Polysomnography (PSG), the system proposed in this project is a non-invasive sleep monitoring device. For continuous analysis or home use, the PSG or wearable Actigraphy devices tends to be uncomfortable. Besides this fact, they are also very expensive. The system represented in this work classifies respiration and body movement with only one type of sensor and also in a non-invasive way. The sensor used is a pressure sensor. This sensor is low cost and can be used for commercial proposes. The system was tested by carrying out an experiment that recorded the sleep process of a subject. These recordings showed the potential for classification of breathing rate and body movements. Although previous researches show the use of pressure sensors in recognizing posture and breathing, they have been mostly used by positioning the sensors between the mattress and bedsheet. This project however, shows an innovative way to position the sensors under the mattress.
ABCdarium of a journey
(2017)
Successful project management (PM), as one of the most important key competences in the western-oriented working world, is mainly influenced by experience and social skills. As a direct impact on PM training, the degree of practice and reality is crucial for the application of lessons learned in a challenging everyday work life. This work presents a recursive approach that adapts well-known principles of PM itself for PM training. Over three years, we have developed a concept and an integrated software system that support our PM university courses. Stepwise, it transfers theoretical PM knowledge into realistic project phases by automatically adjusting to the individual learning progress. Our study reveals predictors such as degrees of collaboration or weekend work as vital aspects in the PM training progress. The chosen granularity of project phases with variances in different dimensions makes our model a canonical incarnation of seamless learning.
Business models (BM) are the logic of a firm on how to create, deliver and capture value. Business model innovation (BMI) is essential to organisations for keeping competitive advantage. However, the existence of barriers to BMI can impact the success of a corporate strategic alignment. Previous research has examined the internal barriers to business model innovation, however there is a lack of research on the potential external barriers that could potentially inhibit business model innovation. Drawn from an in-depth case study in a German medium size engineering company in the equestrian sports industry, we explore both internal and external barriers to business model innovation. BMI is defined as any change in one or more of the nine building blocks of the Business Model Canvas; customer segment, value propositions, channels, customer relation, revenue streams, key resources, key activities, key partners, cost structure [1]. Our results show that barriers to business model innovation can be overcome by the deployment of organisational learning mechanisms and the development of an open network capability.
The Universal Serial Bus (USB) is a worldwide standard for communication between peripherals. Nowadays USB interfaces are integrated in almost every device. It will be used to connect peripherals and computers. USB devices communicate between pieces of hardware, i.e., cable, plug and socket. Thus, there exists different standardized communication protocols depending on the application. In case of different communication protocols, it is necessary to verify them, that devices, no matter of country, can communicate to each other.
The verifying process is very important in order that companies can sell products with such interfaces and their designated logo, to guaranty a certain standard, which is provided all over the world. Devices have to complete various test procedures to get certified. Otherwise a company is not allowed to use logos ore designations, i.e., USB or information about data rates, i.e., SuperSpeed. Furthermore, successfully completed test procedures prove that a device works properly based on a professional method.
The Human-Machine-Interface (HMI) device family from the company Marquardt Verwaltungs GmbH, is using the USB interface for service and data exchange purposes. The service application is realized through a Virtual COM Port (VCP), based on the Communication Device Class (CDC) of USB. On the other side they want to use the Media Transfer Protocol (MTP) based on the Still Image Capture Device class for data exchange between the HMI device and a computer. Of course, the integrated circuit, which implements the USB interface on the circuit board of the HMI device has to be verified, too. The verification will be performed through an external company. In contrast, the communication protocols do not need a verification but must be examined. The identification of an USB class in an operating system does neither guaranty a proper functionality nor comply with a professional scientific method.
To accelerate the development of a project as well as to reduce the production costs, it is a significant advantage to own a test environment. Microsoft provides the possibility to verify devices on Windows operating systems. Therefor they invented the Windows Certification Program, which contains software that can be used for verification purposes. One of them is the Windows Hardware Certification Kit (HCK) we want to set up and set the HMI device under test, to examine the implementation of MTP.
Thus, it is possible to use the HCK test setup during a development process to examine a current implementation without a big effort, i.e., cooperation with an external company or similarly approaches, which delays the whole development process by far.
Validity of the business model is a key indicator for buying into ventures in the early-stage. Business models of early-stage ventures decrease in validity when developing the business over the progressing stages of the business life-cycle. By doing so, the ventures are validating their business model when building transaction relationships to the surrounding value network. In prior research, we developed a research design based on existing business innovation proposals (onepager, pitch decks, business plans) that is assumed to evaluate the status of business model validation. The core hypothesis of the research design is that transaction relations represent a strong anchor between the business model and the business reality, thus providing information on the business model validity. In this research, we test this hypothesis by designing and analyzing a survey that was directed to founders taking part in a business plan competition. We compared the relationships described in the submitted business plans to the relations explicitely stated in the follow-up questionnaire. We identified that the described relations to customers, investors, and people (human resources) match the relationships expressed in questionnaires quite well. A significant disagreement, however, exists in the relationships to suppliers. We conclude that there is still a theoretical and empirical gap that leads to disagreement between business plans and reality in the group of suppliers.
Corporate entrepreneurship (CE) supports the strategic renewal of established companies. Corporate venturing represents one key concept of CE that supports companies to strengthen their innovation capabilities. For the successful implementation of corporate ventures dual structures are recommended. The question, how the interface should be designed, plays a crucial role. Although it seems to be an important factor, this aspect requires further attention. One relevant element of the interface design are the different roles of the individuals that are interacting within the interface. This study is based on nine interviews that are representing six internal corporate ventures within one large German corporate from the ICT sector. The results that were mirrored with short case studies of 25 additional companies of the data sample, contribute to a better understanding of the interface design by adding insights about roles in corporate entrepreneurship. This deeper understanding about roles allows to draw conclusions on the interface design from a structural point of view.
As a result of increasing needs and shrinking resources, aquaculture is gaining progressively significance in the recent years. Ecological issues such as negative effects on the ecological system due to the high fish density in the farms, the use of copper as antifouling strategy etc. are very present, particularly regarding the increasing number of fish going to be produced in farms in the future. Current trends focus on larger farms operated offshore. To make these farms working safe and economical, reliability has to be improved and maintenance costs need to be reduced. Also, alternatives with higher mechanical strength compared to current textile net materials as well as common metal wires might be necessary. In the last years, a new net system made of high strength duplex stainless steel wires with environmentally friendly antifouling properties suitable for offshore applications was developed. The first nets are operating for one year now as predator protection (i.e. seals) for fish farms and show a good performance in cleaning capability and predator protection. But in the real usage, some corrosion effects in the contact points of the net made of duplex stainless steel 1.4362 occur which were not observed in preliminary tests in laboratory and at different test sites around the world. These corrosion effects endanger the sustainable success of the net system. In this work, the observed corrosion effects are investigated. A laboratory test, which simulates the movement in the contact points of the net, was developed. Two pieces of wire are bent in the middle and get stucked into each other. One wire is fixed at both ends and the second wire is fixed on one end. On the other end, a circular movement with 1-2 rps and a 1 cm displacement is applied. The movement generates friction between the wires and the passive layer will be locally damaged. When the movement stops, a repassivation starts. The passivity breakdown and the repassivation were measured with electrochemical techniques. During the friction phase, when the surface will be activated, the open circuit potential breaks down. When the friction stops, the OCP increases. Between the movement phases, measurements of critical pitting potential were done. Thereby the quality of repassivation was investigated. The tests were done in a 3% sodium chloride solution. Different temperatures were tested as well as the influence of air saturation and low oxygen content.
Deep 3D
(2017)
Vortrag
Design of tension components
(2017)
The paper gives an introduction as well as background information on proposed changes and amendments in EN 1993-1-11 “Design of structures with tension components”, implemented during the ongoing revision. Due to some deficits in the currently applicable standard this revision is not only limited to some restructuring and editorial changes, but includes also major technical changes in the following fields: safety concept and structural analysis, actions and loads, robustness and rep-arability, design of tension components and design of clamps and saddles.
We present an analysis of how to determine security requirements for software that controls routing decisions in the distribution of discrete physical goods. Requirements are derived from stakeholder interests and threat scenarios. Three deployment scenarios are discussed: cloud and hybrid deployment as well as on-premise installation for legacy sites.
Poster
Earthquake engineering
(2017)
Vortrag
Efficient privacy-preserving configurationless service discovery supporting multi-link networks
(2017)
Data is the pollution problem of the information age, and protecting privacy is the environmental challenge — this quotation from Bruce Schneier laconically illustrates the importance of protecting privacy. Protecting privacy — as well as protecting our planet — is fundamental for humankind. Privacy is a basic human right, stated in the 12th article of the United Nations’ Universal Declaration of Human Rights. The necessity to protect human rights is unquestionable. Nothing ever threatened privacy on a scale comparable to today’s interconnected computers. Ranging from small sensors over smart phones and notebooks to large compute clusters, they collect, generate and evaluate vast amounts of data. Often, this data is distributed via the network, not only rendering it accessible to addressees, but also — if not properly secured — to malevolent parties. Like a toxic gas, this data billows through networks and suffocates privacy. This thesis takes on the challenge of protecting privacy in the area of configurationless service discovery. Configurationless service discovery is a basis for user-friendly applications. It brings great benefits, allowing the configurationless network setup for various kinds of applications; e.g. for communicating, sharing documents and collaborating, or using infrastructure devices like printers. However, while today’s various protocols provide some means of privacy protection, typical configurationless service discovery solutions do not even consider privacy. As configurationless service discovery solutions are ubiquitous and run on almost every smart device, their privacy problems affect almost everyone. The quotation aligns very well with configurationless service discovery. Typically, configurationless service discovery solutions realize configurationlessness by using cleartext multicast messages literally polluting the local network and suffocating privacy. Messages containing private cleartext data are sent to everyone, even if they are only relevant for a few users. The typical means for mitigating the network pollution problem caused by multicast per se, regardless of the privacy aspects, is confining multicast messages to a single network link or to the access network of a WiFi access point; institutions often even completely deactivate multicast. While this mitigates the privacy problem, it also strongly scales configurationless service discovery down, either confining it or rendering it completely unusable. In this thesis, we provide an efficient configurationless service discovery framework that protects the users’ privacy. It further reduces the network pollution by reducing the number of necessary multicast messages and offers a mode of operation that is completely independent of multicast. Introducing a multicast independent mode of operation, we also address the problem of the limited range in which services are discoverable. Our framework comprises components for device pairing, privacy-preserving service discovery, and multi-link scaling. These components are independent and — while usable in a completely separated way — are meant to be used as an integrated framework as they work seamlessly together. Based on our device pairing and privacy-preserving service discovery components, we published IETF Internet drafts specifying a privacy extension for DNS service discovery over multicast DNS, a wildly used protocol stack for configurationless service discovery. As our drafts have already been adopted by the dnssd working group, they are likely to become standards.
Koreferat zum Vortrag
The electrochemical behavior for different surface conditions and different degrees of deformation of metastable austenitic stainless steel AISI 304 UNS S30400 were studied using critical pitting potential and electrochemical noise measurements. The influence on corrosion resistance by using different abrasives (silicon carbide and corundum) for surface finish by grinding is illustrated. For the characterization of local defects and surface topography, scanning electron microscopy (SEM) and tactile measurements were used. An inverse correlation between occurrence of local defects on the surface and critical pitting potential was found by using image processing. Therefore, gray scale values of different surfaces were compared. The influence of mass content of α'-martensite on the corrosion resistance is shown by comparing different qualities of surface finish. For smooth machined surfaces it can be shown that an increasing numbers of strain induced martensite is decreasing the corrosion resistance lightly. For low abrasive machining an inverse correlation between the critical pitting potential and surface roughness is given. However, for higher abrasive machining parameters, this correlation could not be found.
Error correction coding based on soft-input decoding can significantly improve the reliability of flash memories. Such soft-input decoding algorithms require reliability information about the state of the memory cell. This work proposes a channel model for soft-input decoding that considers the asymmetric error characteristic of multi-level cell (MLC) and triple-level cell (TLC) memories. Based on this model, an estimation method for the channel state information is devised which avoids additional pilot data for channel estimation. Furthermore, the proposed method supports page-wise read operations.
The estimation of the holding periods of financial products has to be done in a dynamic process in which the size of the observation time interval influences the result. Small intervals will produce smaller average holding periods than bigger ones. The approach developed in this paper offers the possibility of estimating this average independently of the size of this time interval. This method is demonstrated on the example of two distributions, based on the exponential and the geometric probability functions. The estimation will be found by maximizing the likelihood function.
In the reverse engineering process one has to classify parts of point clouds with the correct type of geometric primitive. Features based on different geometric properties like point relations, normals, and curvature information can be used, to train classifiers like Support Vector Machines (SVM). These geometric features are estimated in the local neighborhood of a point of the point cloud. The multitude of different features makes an in-depth comparison necessary. In this work we evaluate 23 features for the classification of geometric primitives in point clouds. Their performance is evaluated on SVMs when used to classify geometric primitives in simulated and real laser scanned point clouds. We also introduce a normalization of point cloud density to improve classification generalization.
Tests for speeding up the determination of the Bernstein enclosure of the range of a multivariate polynomial and a rational function over a box and a simplex are presented. In the polynomial case, this enclosure is the interval spanned by the minimum and the maximum of the Bernstein coefficients which are the coefficients of the polynomial with respect to the tensorial or simplicial Bernstein basis. The methods exploit monotonicity properties of the Bernstein coefficients of monomials as well as a recently developed matrix method for the computation of the Bernstein coefficients of a polynomial over a box.
Growth is a key indicator of the prosperity of an economy. In today's Germany the " Gründerzeit " still describes a period of enormous economic growth. Factors that lead to growth haven't been investigated in the context of the different life cycle stages of early-stage technology ventures so far. This paper proposes a model of early-stage ventures' growth based on factors. From a theoretical angle, we look at the business from the market-based view (MBV) and the resource-based view (RBV) on strategy in the longitudinal perspective of the business life cycle. With this view we get to know what are the stage specific needs and processes of new technology based ventures in order to provide appropriate support. We tested different potential growth indicators for the model with a questionnaire-based survey which was answered by 68 high-tech entrepreneurs. The results suggest that growth factors are stage specific in their relevance. While leading to growth in one stage, certain factors evince no or even negative influence on growth in other stages. Moreover, RBV factors as seen more relevant for the growth than the MBV factors. Further research requires a large and representative population to validate the results. Keywords:-growth factors, early-stage ventures, market-based view, resources based view.
To evaluate the quality of sleep, it is important to determine how much time was spent in each sleep stage during the night. The gold standard in this domain is an overnight polysomnography (PSG). But the recording of the necessary electrophysiological signals is extensive and complex and the environment of the sleep laboratory, which is unfamiliar to the patient, might lead to distorted results. In this paper, a sleep stage detection algorithm is proposed that uses only the heart rate signal, derived from electrocardiogram (ECG), as a discriminator. This would make it possible for sleep analysis to be performed at home, saving a lot of effort and money. From the heart rate, using the fast Fourier transformation (FFT), three parameters were calculated in order to distinguish between the different sleep stages. ECG data along with a hypnogram scored by professionals was used from Physionet database, making it easy to compare the results. With an agreement rate of 41.3%, this approach is a good foundation for future research.
InBetween
(2017)
Industry 4.0
(2017)