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In automotive a lot of electromagnetically, pyrotechnically or mechanically driven actuators are integrated to run comfort systems and to control safety systems in modern passenger cars. Using shape memory alloys (SMA) the existing systems could be simplified, performing the same function through new mechanisms with reduced size, weight, and costs. A drawback for the use of SMA in safety systems is the lack of materials knowledge concerning the durability of the switching function (long-time stability of the shape memory effect). Pedestrian safety systems play a significant role to reduce injuries and fatal casualties caused by accidents. One automotive safety system for pedestrian protection is the bonnet lifting system. Based on such an application, this article gives an introduction to existing bonnet lifting systems for pedestrian protection, describes the use of quick changing shape memory actuators and the results of the study concerning the long-time stability of the tested NiTi-wires. These wires were trained, exposed up to 4years at elevated temperatures (up to 140°C) and tested regarding their phase change temperatures, times, and strokes. For example, it was found that A P-temperature is shifted toward higher temperatures with longer exposing periods and higher temperatures. However, in the functional testing plant a delay in the switching time could not be detected. This article gives some answers concerning the long-time stability of NiTi-wires that were missing till now. With this knowledge, the number of future automotive applications using SMA can be increased. It can be concluded, that the use of quick changing shape memory actuators in safety systems could simplify the mechanism, reduce maintenance and manufacturing costs and should be insertable also for other automotive applications.
The effect on the mean-variance space of restrictions on a variable is investigated in this
paper. A restriction may be the placing of upper and lower bounds on a variable.
Another limitation is the loss of the continuity of a variable.
Average marks for Examinations are considered in an application of this limited meanvariance
space. In this case, the bounds are given by the highest and the lowest possible mark (e.g. 1.0 and 5.0). The limitation of the mean-variance space depends on the number of students who participate in the examination. The restriction of the loss of continuity is shown by the use of discrete marks (e.g. 1.0, 1.3, 1.7, 2.0, …). Furthermore,
the Target-Shortfall-Probability lines are integrated into the mean-variance space. These
lines are used to indicate the proportion of students who have good or very good marks in the examination. In financial markets, Target-Shortfall-Probability is used as a risk criterion.
Characterization of NiTi Shape Memory Damping Elements designed for Automotive Safety Systems
(2014)
Actuator elements made of NiTi shape memory material are more and more known in industry because of their unique properties. Due to the martensitic phase change, they can revert to their original shape by heating when subjected to an appropriate treatment. This thermal shape memory effect (SME) can show a significant shape change combined with a considerable force. Therefore such elements can be used to solve many technical tasks in the field of actuating elements and mechatronics and will play an increasing role in the next years, especially within the automotive technology, energy management, power, and mechanical engineering as well as medical technology. Beside this thermal SME, these materials also show a mechanical SME, characterized by a superelastic plateau with reversible elongations in the range of 8%. This behavior is based on the building of stress-induced martensite of loaded austenite material at constant temperature and facilitates a lot of applications especially in the medical field. Both SMEs are attended by energy dissipation during the martensitic phase change. This paper describes the first results obtained on different actuator and superelastic NiTi wires concerning their use as damping elements in automotive safety systems. In a first step, the damping behavior of small NiTi wires up to 0.5 mm diameter was examined at testing speeds varying between 0.1 and 50 mm/s upon an adapted tensile testing machine. In order to realize higher testing speeds, a drop impact testing machine was designed, which allows testing speeds up to 4000 mm/s. After introducing this new type of testing machine, the first results of vertical-shock tests of superelastic and electrically activated actuator wires are presented. The characterization of these high dynamic phase change parameters represents the basis for new applications for shape memory damping elements, especially in automotive safety systems.
Atom interferometers have a multitude of proposed applications in space including precise measurements of the Earth's gravitational field, in navigation & ranging, and in fundamental physics such as tests of the weak equivalence principle (WEP) and gravitational wave detection. While atom interferometers are realized routinely in ground-based laboratories, current efforts aim at the development of a space compatible design optimized with respect to dimensions, weight, power consumption, mechanical robustness and radiation hardness. In this paper, we present a design of a high-sensitivity differential dual species 85Rb/87Rb atom interferometer for space, including physics package, laser system, electronics and software. The physics package comprises the atom source consisting of dispensers and a 2D magneto-optical trap (MOT), the science chamber with a 3D-MOT, a magnetic trap based on an atom chip and an optical dipole trap (ODT) used for Bose-Einstein condensate (BEC) creation and interferometry, the detection unit, the vacuum system for 10-11 mbar ultra-high vacuum generation, and the high-suppression factor magnetic shielding as well as the thermal control system.
The laser system is based on a hybrid approach using fiber-based telecom components and high-power laser diode technology and includes all laser sources for 2D-MOT, 3D-MOT, ODT, interferometry and detection. Manipulation and switching of the laser beams is carried out on an optical bench using Zerodur bonding technology. The instrument consists of 9 units with an overall mass of 221 kg, an average power consumption of 608 W (819 W peak), and a volume of 470 liters which would well fit on a satellite to be launched with a Soyuz rocket, as system studies have shown.
The problem of vessel collisions or near-collision situations on sea, often caused by human error due to incomplete or overwhelming information, is becoming more and more important with rising maritime traffic. Approaches to supply navigators and Vessel Traffic Services with expert knowledge and suggest trajectories for all vessels to avoid collisions, are often aimed at situations where a single planner guides all vessels with perfect information. In contrast, we suggest a two-part procedure which plans trajectories using a specialised A* and negotiates trajectories until a solution is found, which is acceptable for all vessels. The solution obeys collision avoidance rules, includes a dynamic model of all vessels and negotiates trajectories to optimise globally without a global planner and extensive information disclosure. The procedure combines all components necessary to solve a multi-vessel encounter and is tested currently in simulation and on several test beds. The first results show a fast converging optimisation process which after a few negotiation rounds already produce feasible, collision free trajectories.
Codes over quotient rings of Lipschitz integers have recently attracted some attention. This work investigates the performance of Lipschitz integer constellations for transmission over the AWGN channel by means of the constellation figure of merit. A construction of sets of Lipschitz integers that leads to a better constellation figure of merit compared to ordinary Lipschitz integer constellations is presented. In particular, it is demonstrated that the concept of set partitioning can be applied to quotient rings of Lipschitz integers where the number of elements is not a prime number. It is shown that it is always possible to partition such quotient rings into additive subgroups in a manner that the minimum Euclidean distance of each subgroup is strictly larger than in the original set. The resulting signal constellations have a better performance for transmission over an additive white Gaussian noise channel compared to Gaussian integer constellations and to ordinary Lipschitz integer constellations. In addition, we present multilevel code constructions for the new signal constellations.
This paper proposes a pipelined decoder architecture for generalised concatenated (GC) codes. These codes are constructed from inner binary Bose-Chaudhuri-Hocquenghem (BCH) and outer Reed-Solomon codes. The decoding of the component codes is based on hard decision syndrome decoding algorithms. The concatenated code consists of several small BCH codes. This enables a hardware architecture where the decoding of the component codes is pipelined. A hardware implementation of a GC decoder is presented and the cell area, cycle counts as well as the timing constraints are investigated. The results are compared to a decoder for long BCH codes with similar error correction performance. In comparison, the pipelined GC decoder achieves a higher throughput and has lower area consumption.
Bernstein polynomials on a simplex V are considered. The expansion of a given polynomial p into these polynomials provides bounds for range of p over V. Bounds for the range of a rational function over V can easily be obtained from the Bernstein expansions of the numerator and denominator polynomials of this function. In this paper it is shown that these bounds converge monotonically and linearly to the range of the rational function if the degree of the Bernstein expansion is elevated. If V is subdivided then the convergence is quadratic with respect to the maximum of the diameters of the subsimplices.
Sleep is an important aspect in life of every human being. The average sleep duration for an adult is approximately 7 h per day. Sleep is necessary to regenerate physical and psychological state of a human. A bad sleep quality has a major impact on the health status and can lead to different diseases. In this paper an approach will be presented, which uses a long-term monitoring of vital data gathered by a body sensor during the day and the night supported by mobile application connected to an analyzing system, to estimate sleep quality of its user as well as give recommendations to improve it in real-time. Actimetry and historical data will be used to improve the individual recommendations, based on common techniques used in the area of machine learning and big data analysis.
The corrosion resistance of stainless steels is massively influenced by the condition of their surface. The surface quality includes the topography of the surface, the structure and composition of the passive layer, and the surface near structure of the base material. These factors are influenced by final physical/chemical surface treatments. The presented work shows significantly lower corrosion resistance for mechanical machined specimens than for etched specimens. It also turns out that the rougher the surface, the lower the corrosion resistance gets. However, there is no general finding which shows if blasted or grinded surfaces are more appropriate, but a dependency on process parameters and the characteristics on corrosive exposure in terms of corrosion behavior. The results show that not only the surface roughness Ra has an influence on corrosion behavior but also the shape of peaks and valleys which are evolved by surface treatments. Imperfections in the base material, like sulfidic inclusions lead to a weaker passive layer, respectively, to a decrease of the corrosion resistance. By using special passivating techniques the corrosion resistance of stainless steels can be increased to a higher level in comparison to common passivation.
Even though immutability is a desirable property, especially in a multi-threaded environment, implementing immutable Java classes is surprisingly hard because of a lack of language support. We present a static analysis tool using abstract bytecode interpretation that checks Java classes for compliance with a set of rules that together constitute state-based immutability. Being realized as a Find Bugs plug in, the tool can easily be integrated into most IDEs and hence the software development process. Our evaluation on a large, real world codebase shows that the average run-time effort for a single class is in the range of a few milliseconds, with only a very few statistical spikes.
To learn from the past, we analyse 1,088 "computer as a target" judgements for evidential reasoning by extracting four case elements: decision, intent, fact, and evidence. Analysing the decision element is essential for studying the scale of sentence severity for cross-jurisdictional comparisons. Examining the intent element can facilitate future risk assessment. Analysing the fact element can enhance an organization's capability of analysing criminal activities for future offender profiling. Examining the evidence used against a defendant from previous judgements can facilitate the preparation of evidence for upcoming legal disclosure. Follow the concepts of argumentation diagrams, we develop an automatic judgement summarizing system to enhance the accessibility of judgements and avoid repeating past mistakes. Inspired by the feasibility of extracting legal knowledge for argument construction and employing grounds of inadmissibility for probability assessment, we conduct evidential reasoning of kernel traces for forensic readiness. We integrate the narrative methods from attack graphs/languages for preventing confirmation bias, the argumentative methods from argumentation diagrams for constructing legal arguments, and the probabilistic methods from Bayesian networks for comparing hypotheses.
ERP systems integrate a major part of all business processes and organizations include them in their IT service management. Besides these formal systems, there are additional systems that are rather stand-alone and not included in the IT management tasks. These so-called ‘shadow systems’ also support business processes but hinder a high enterprise integration. Shadow systems appear during their explicit detection or during software maintenance projects such as enhancements or release changes of enterprise systems. Organizations then have to decide if and to what extent they integrate the identified shadow systems into their ERP systems. For this decision, organizations have to compare the capabilities of each identified shadow system with their ERP systems. Based on multiple-case studies, we provide a dependency approach to enable their comparison. We derive categories for different stages of the dependency and base insights into integration possibilities on these stages. Our results show that 64% of the shadow systems in our case studies are related to ERP systems. This means that they share parts or all of their data and/or functionality with the ERP system. Our research contributes to the field of integration as well as to the discussion about shadow systems.
This paper proposes a soft input decoding algorithm and a decoder architecture for generalized concatenated (GC) codes. The GC codes are constructed from inner nested binary Bose-Chaudhuri-Hocquenghem (BCH) codes and outer Reed-Solomon codes. In order to enable soft input decoding for the inner BCH block codes, a sequential stack decoding algorithm is used. Ordinary stack decoding of binary block codes requires the complete trellis of the code. In this paper, a representation of the block codes based on the trellises of supercodes is proposed in order to reduce the memory requirements for the representation of the BCH codes. This enables an efficient hardware implementation. The results for the decoding performance of the overall GC code are presented. Furthermore, a hardware architecture of the GC decoder is proposed. The proposed decoder is well suited for applications that require very low residual error rates.
Domain-Specific modelling is increasingly adopted in the software development industry. While textual domain specific languages (DSLs) already have a wide impact, graphical DSLs still need to live up to their full potential. In this paper we describe an approach that reduces the time to create a graphical DSL to hours instead of months. The paper describes a generative approach to the creation of graphical editors for the Eclipse platform. A set of carefully designed textual DSLs together with an EMF meta-model are the input for the generator. The output is an Eclipse plugin for a graphical editor for the intended graphical language. The entire project is made available as open source under the name Spray and is being developed by an active community. This paper focuses on the description of the workflow and provides an introduction into the possibilities through this approach of a graphical modelling environment.
Domain-specific modeling is more and more understood as a comparable solution compared to classical software development. Textual domain-specific languages (DSLs) already have a massive impact in contrast tographical DSLs, they still have to show their full potential. The established textual DSLs are normally generated from a domain specific grammar or maybe other specific textual descriptions. And advantage of textual DSLs is that they can be development cost-efficient.
In this paper, we describe asimilar approach for the creation of graphical DSLs from textual descriptions. We present a set of specially developed textual DSLs to fully describe graphical DSLs based on node and edge diagrams. These are, together with an EMF meta-model, the input for a generator that produces an eclipse-based graphical Editor. The entire project is available as open source under the name MoDiGen.
Domain-specific modeling is increasingly adopted by the software development industry. While textual domain-specific languages (DSLs) already have a wide impact, graphical DSLs still need to live up to their full potential. Textual DSLs are usually generated from a grammar or other short textual notations; their development is often cost-efficient. In this paper, we describe an approach to similarly create graphical DSLs from textual notations. The paper describes an approach to generate a graphical node and edge online editor, using a set of carefully designed textual DSLs to fully describe graphical DSLs. Combined with an adequate metamodel, these textual definitions represent the input for a generator that produces a graphical Editor for the web with features such as collaboration, online storage and being always available. The entire project is made available as open source under the name Zeta. This paper focuses on the overall approach and the description of the textual DSLs that can be used to develop graphical modeling languages and editors.
This letter introduces signal constellations based on multiplicative groups of Eisenstein integers, i.e., hexagonal lattices. These sets of Eisenstein integers are proposed as signal constellations for generalized spatial modulation. The algebraic properties of the new constellations are investigated and a set partitioning technique is developed. This technique can be used to design coded modulation schemes over hexagonal lattices.
The Kerala tourism model
(2017)
Sustainable tourism in Kerala is on the rise. Therefore, this South Indian state is assessed according to the sustainable tourism criteria of the Strasdas et al. (2007) framework. Kerala as a state does not qualify as a sustainable tourism destination, although individual success stories at the NGO and government level exist. This conceptual paper delivers a detailed analysis of the three dimensions of sustainability, i.e. ecology, economy and socio-cultural aspects, of the ‘Kerala tourism model’ and discusses the question of whether this model can be transferred to other developing countries. Copyright © 2016 John Wiley & Sons, Ltd and ERP Environment
Purpose The purpose of this paper is to find out tourism movement patterns via the tracking of tourists with the help of positioning systems like GPS in the rural area of the Lake Constance destination in Germany. In doing so past, present and future of tourist tracking is illustrated. Design/methodology/approach The tracking is realized via common smartphones extended by an app, with dedicated sensors like position loggers and a survey. The three different approaches are applied in order to compare and cross-check results (triangulation of data and methods). Findings Movement patterns turned out to be diverse and individualistic within the rural destination of Lake Constance and following an ants trail in sub-destinations like the city of Constance. Repeat visitors and first-time visitors alike always visit the bigger cities and main day-trip destinations of the Lake. A possible prediction tool enables new avenues of governing tourism movement patterns. Research limitations/implications The tracking techniques can be developed further into the direction of “quantified self” using gamification in order to make the tracking app even more attractive. Practical implications An algorithm-based prediction tool would offer new perspectives to the management of tourism movements. Social implications Further research is needed to overcome the feeling of invasiveness of the app to allow tracking with that approach. Originality/value This study is original and innovative because of the first-time use of a smartphone app in tourist tracking, the application on a rural destination and the conceptual description of a prediction tool.
Software startups
(2016)
Software startup companies develop innovative, software-intensive products within limited time frames and with few resources, searching for sustainable and scalable business models. Software startups are quite distinct from traditional mature software companies, but also from micro-, small-, and medium-sized enterprises, introducing new challenges relevant for software engineering research. This paper’s research agenda focuses on software engineering in startups, identifying, in particular, 70+ research questions in the areas of supporting startup engineering activities, startup evolution models and patterns, ecosystems and innovation hubs, human aspects in software startups, applying startup concepts in non-startup environments, and methodologies and theories for startup research. We connect and motivate this research agenda with past studies in software startup research, while pointing out possible future directions. While all authors of this research agenda have their main background in Software Engineering or Computer Science, their interest in software startups broadens the perspective to the challenges, but also to the opportunities that emerge from multi-disciplinary research. Our audience is therefore primarily software engineering researchers, even though we aim at stimulating collaborations and research that crosses disciplinary boundaries. We believe that with this research agenda we cover a wide spectrum of the software startup industry current needs.
The multichannel Wiener filter (MWF) is a well-established noise reduction technique for speech processing. Most commonly, the speech component in a selected reference microphone is estimated. The choice of this reference microphone influences the broadband output signal-to-noise ratio (SNR) as well as the speech distortion. Recently, a generalized formulation for the MWF (G-MWF) was proposed that uses a weighted sum of the individual transfer functions from the speaker to the microphones to form a better speech reference resulting in an improved broadband output SNR. For the MWF, the influence of the phase reference is often neglected, because it has no impact on the narrow-band output SNR. The G-MWF allows an arbitrary choice of the phase reference especially in the context of spatially distributed microphones.
In this work, we demonstrate that the phase reference determines the overall transfer function and hence has an impact on both the speech distortion and the broadband output SNR. We propose two speech references that achieve a better signal-to-reverberation ratio (SRR) and an improvement in the broadband output SNR. Both proposed references are based on the phase of a delay-and-sum beamformer. Hence, the time-difference-of-arrival (TDOA) of the speech source is required to align the signals. The different techniques are compared in terms of SRR and SNR performance.
Domain-specific modeling is increasingly adopted in the software development industry. While textual domain-specific languages (DSLs) already have a wide impact, graphical DSLs still need to live up to their full potential. In this paper, we describe an approach to automatically generate a graphical DSL from a set of textual languages. With our approach, node and edge type graphical DSLs can be described using textual models. A set of carefully designed textual DSLs is the input for our generators. The result of the generation is a graphical editor for the intended domain. The development time for a graphical editor is reduced significantly. The whole project is available as open source under the name "Zeta". This publication focuses on the explanation of the textual DSLs for defining a graphical node and edge editor.
A real matrix is called totally nonnegative if all of its minors are nonnegative. In this paper the extended Perron complement of a principal submatrix in a matrix A is investigated. In extension of known results it is shown that if A is irreducible and totally nonnegative and the principal submatrix consists of some specified consecutive rows then the extended Perron complement is totally nonnegative. Also inequalities between minors of the extended Perron complement and the Schur complement are presented.
This paper considers intervals of real matrices with respect to partial orders and the problem to infer from some exposed matrices lying on the boundary of such an interval that all real matrices taken from the interval possess a certain property. In many cases such a property requires that the chosen matrices have an identically signed inverse. We also briefly survey related problems, e.g., the invariance of matrix properties under entry-wise perturbations.
So is About Urbanity
(2016)
Südstadt Tübingen is a successful military land redevelopment project, in which functional mix and urban diversity have been identified as main goals. In the whole development process, joint building venture has been utilized as important urban development instrument. On one hand, this instrument helps citizens development adaptive and affordable living space and let them find own identity to the new quarter; on the other hand, it is also important to cultivate urban diversity and suitable spatial feeling, mix relationship in living and working conditions, so that the quarters will have very flexible structure to accommodate diversified urban life styles.
In this paper totally nonnegative (positive) matrices are considered which are matrices having all their minors nonnegative (positve); the almost totally positive matrices form a class between the totally nonnegative matrices and the totally positive ones. An efficient determinantal test based on the Cauchon algorithm for checking a given matrix for falling in one of these three classes of matrices is applied to matrices which are related to roots of polynomials and poles of rational functions, specifically the Hankel matrix associated with the Laurent series at infinity of a rational function and matrices of Hurwitz type associated with polynomials. In both cases it is concluded from properties of one or two finite sections of the infinite matrix that the infinite matrix itself has these or related properties. Then the results are applied to derive a sufficient condition for the Hurwitz stability of an interval family of polynomials. Finally, interval problems for a subclass of the rational functions, viz. R-functions, are investigated. These problems include invariance of exclusively positive poles and exclusively negative roots in the presence of variation of the coefficients of the polynomials within given intervals.
This paper builds upon the widely-used resource-based approach to explaining survival of new technology-based firms (NTBFs). However, instead of looking at the NTBF's initial resource configuration, a process-oriented perspective is taken by focusing on the entrepreneur's ability to transform resources in response to triggers resulting from market interactions. Transaction relations reflect these interactions and are thus operationalized with a suggested method for measuring the status of venture emergence (VE) applicable to early-stage NTBFs. NTBFs' value network maturity is reflected in the number and strength of their transaction relations in the four market dimensions customer, investor, partner, and human resource. Business plans of NTBFs represent the artifact that contains this data in the form of transaction relation descriptions. Using content analysis, a multi-step combined human and computer coding process has been developed to annotate and classify transaction relations from business plans in order to empirically determine NTBFs' status of VE. Results of the business plan analysis suggest that the level of transaction relations allows to draw conclusions on the VE status. Moreover, applying the developed process, first analysis of a business plan coding test shows that the transaction relation based VE status significantly relates to NTBF survival capability.
As part of large-scale project in the Lake Constance region that borders Germany, Austria and Switzerland, seamless learning prototypes are designed, implemented, and evaluated. A design-based research (DBR) approach is used for the development, implementation and evaluation. The project consists of one base project that brings together instructional design and instructional technology specialists as well as (educational) software architects, supporting seven subprojects in developing seamless-learning lighthouse implementations mostly within higher and further education.
Industrial partners are involved in all subprojects. The authors are unaware of similar seamless learning projects using a DBR approach that include evaluation and redesign and allow for comparison of experiences by applying DBR across subprojects. The project aims to generate novel seamless learning implementations, respective novel research and novel software supporting different aspects of seamless learning. The poster will present the project design, delineate areas of research and development, and include initial empirical results.
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 extended object tracking, a target is capable to generate more than one measurement per scan. Assuming the target being of elliptical shape and given a point cloud of measurements, the Random Matrix Framework can be applied to concurrently estimate the target’s dynamic state and extension. If the point cloud contains also clutter measurements or origins from more than one target, the data association problem has to be solved as well. However, the well-known joint probabilistic data association method assumes that a target can generate at most one detection. In this article, this constraint is relaxed, and a multi-detection version of the joint integrated probabilistic data association is proposed. The data association method is then combined with the Random Matrix framework to track targets with elliptical shape. The final filter is evaluated in the context of tracking smaller vessels using a high resolution radar sensor. The performance of the filter is shown in simulation and in several experiments.
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.
Rethinking Compliance
(2017)
In the past Compliance Management has often failed, the Volkswagen emissions scandal just being one prominent example. Not everything has to be reinvented, and not everything that companies have done in the past regarding Compliance is wrong. But it is about time to think Compliance in new ways. What does “Compliance Management 2.0” really depend on? The following article aims at laying out the cornerstones for enduring effective Compliance which amongst others comprises sincerity and credibility and a moral foundation. Furthermore, the commitment and role model behavior of top managers and the training of line managers are crucial for the effectiveness of any Compliance Management System (CMS). Ultimately, for Compliance to function efficiently the efforts must be adequate for the respective company and realistic regarding the achievable goals.
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.
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.
Smart factory and education
(2017)
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.
R concretes with a proportion of recycled aggregates are standardized normal concretes which are allowed for use in Germany up to strength class C30/37. Because of the good technical properties and the ecological advantages, the article presents possible applications in the field of concrete products and precast concrete elements. Read part 2 of the paper.
R concretes with a proportion of recycled aggregates are standardized normal concretes which are allowed for use in Germany up to strength class C30/37. Because of the good technical properties and the ecological advantages, the article presents possible applications in the field of concrete products and precast concrete elements. Read part 1 of the paper.
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.