Ernteresultate Bioraps 2011: Erträge durchschnittlich

Ernteresultate Bioraps 2011: Erträge durchschnittlic

Principles for sequencing public financial reforms in developing countries

A substantial number of developing countries are currently undertaking public financial management (PFM) reforms. A central aspect of such reforms is proper sequencing which is currently highly debated in the donor community. This article provides a general overview of the most common approaches for sequencing PFM reforms in developing countries. Such approaches can provide a useful basis for the development of a sequencing strategy. However, interviews with PFM experts and literature analysis showed that these models should not be considered too technical. As a result, the article suggests some principles which the donor community should follow when implementing a PFM sequencing strategy

The Role of Social Media in Social Engineering Attacks: A Qualitative Study on Technical-, Individual-, and Organizational Measures to Mitigate Social Engineering Attacks in Social Media

It is estimated that 98 % of all cyberattacks include some form of social engineering (Rebeca, 2023). The continued relentless cyber-related threats to organizations are ever-growing and important to address to mitigate the risks of being attacked. Social media platforms could be considered as the perfect hunting ground for social engineers to scour user profiles for personal and exploitable information to either deceive users directly or use this information to plan for a future attack. This research focuses on the role of social media in social engineering attacks, more specifically how social engineering can be mitigated from three perspectives: 1) Technical measures that the social media platforms are responsible for implementing, 2) User-related responsibilities, 3) How organizations could facilitate the education and awareness training of their employees on the use of social media. With this research being deductive-based, a systematic literature review (SLR) was conducted to build a foundation of literature of the relevant topics. For the empirical data collection, ten respondents from various international organizations were interviewed, including professionals and researchers in the field of cybersecurity and communication. The interviews were conducted with a semi-structured format. The Cybersecurity Culture Framework from (Gioulekas et al., 2022) was adopted throughout this master thesis, with it also being the foundation for the data analysis. As a result of the empirical findings and the Cybersecurity Culture Framework, it has emerged an inductive conceptual framework with new concepts. Combining the results from both the literature review and the empirical findings, it is apparent that there are several measures, in all three perspectives, that are viable. From the platform and technical perspective, the use of some form of unique identification to remedy the risks of fake accounts and fraud, in addition to the use of AI to predict and prevent potential social engineering attacks is advised. Both from the individual- and organizational aspect, the common denominators are the high focus of training and awareness, both privately and professionally. This includes that users of social media have to familiarize themselves with the terms of use, and realize the consequences of sharing content and information on such platforms

The benchmark black hole in NGC 4258: dynamical models from high-resolution two-dimensional stellar kinematics

NGC 4258 is the galaxy with the most accurate (maser-based) determination for the mass of the supermassive black hole (SMBH) in its nucleus. In this work we present a two-dimensional mapping of the stellar kinematics in the inner 3.0 x 3.0 arcsec = 100 x 100 pc of NGC 4258 using adaptative-optics observations obtained with the Near-Infrared Integral Field Spectrograph of the GEMINI North telescope at a 0.11 arcsec (4 pc) angular resolution. The observations resolve the radius of influence of the SMBH, revealing an abrupt increase in the stellar velocity dispersion within 10 pc from the nucleus, consistent with the presence of a SMBH there. Assuming that the galaxy nucleus is in a steady state and that the velocity dispersion ellipsoid is aligned with a cylindrical coordinate system, we constructed a Jeans anisotropic dynamical model to fit the observed kinematics distribution. Our dynamical model assumes that the galaxy has axial symmetry and is constructed using the multi-gaussian expansion method to parametrize the observed surface brightness distribution. The Jeans dynamical model has three free parameters: the mass of the central SMBH, the mass-luminosity ratio of the galaxy and the anisotropy of the velocity distribution. We test two types of models: one with constant velocity anisotropy, and another with variable anisotropy. The model that best reproduces the observed kinematics was obtained considering that the galaxy has radially varying anisotropy, being the best-fitting parameters with 3$\sigma$ significance $M_\bullet=4.8^{+0.8}_{-0.9}\times 10^7\,{\rm M_\odot}$ and $\Gamma_k = 4.1^{+0.4}_{-0.5}$. This value for the mass of the SMBH is just 25 per cent larger than that of the maser determination and 50 per cent larger that a previous stellar dynamical determination obtained via Schwarzschild models.Comment: Accepted for publication in MNRAS, 19 pages, 19 figure

Dressing of hybrid-bonded graded diamond grinding wheels

For tool grinding, an optimization potential in terms of productivity is available using graded grinding wheels. This is especially the case when grinding flutes in cemented carbide. Due to the properties of the cemented carbide, high radial wear occurs. Depending on the geometry of the flute, the radial wear varies along the engagement width of the grinding tool. The varying radial wear can be compensated by load adapting the grinding tool properties along its engagement width. The adaptation of the wear behaviour to non-uniform engagement conditions results in non-uniform radial wear occurring under uniform engagement conditions. Indeed, this is the case when dressing these grinding tools. Therefore, this publication presents a method that enables the dressing of graded grinding wheels. For this purpose, four differently graded grinding wheels and two non-graded grinding wheels are dressed with SiC-rolls. Different SiC-rolls, as well as dressing parameters, are investigated. The contour accuracy after dressing is analysed using contour profiles in polyurethane. In the presented paper, dressing parameters are proposed which allow reproducible dressing of all grinding wheels used

Operational behaviour of graded diamond grinding wheels for end mill cutter machining

The varying related material removal rate during deep grinding of cemented carbide end mill cutters results in an unevenly wear of the grinding wheel. This study therefore presents a simulation-based model for the load-adjusted design of grinding wheels to achieve balanced radial wear, as well as an evaluation of this model. The related material removal rate along the width of the grinding wheel is determined by a Dexel based material removal simulation for different end mill geometries. Based on these results an equation is derived to adapt the abrasive layer properties to the local load differences. Three grinding wheels with different types of gradients are then manufactured by a grinding tool manufacturer based on this equation. These and two grinding wheels with constant abrasive layer properties are used for deep grinding of ten end mills each. Afterwards the radial wear of each grinding wheel is measured by a confocal microscope. An analysis of the cutting edge chipping is done to evaluate the influence on the graded grinding wheels on the cutting edge quality. It was found that a reduction of the wear difference over the grinding wheel width of 52% and an improved cutting edge quality can be achieved by using graded grinding tools. This allows the time intervals between dressing steps to be increased without compromising the accuracy of the grinding process, thus also increasing its productivity. Finally, this article shows that the presented model allows for a more balanced wear behaviour, but has to be extended by considering further factors influencing radial wear

Sharpening of graded diamond grinding wheels

Grinding the flutes of cemented carbide end mill cutters results in high and uneven radial wear of the grinding wheel. This is a consequence of the varying geometrical contact conditions over the grinding wheel width. Decreased manufacturing accuracy regarding the tool target geometry is the consequence. To compensate for this, the dressing intervals must be shortened. High non-productive times and an additionally reduction of the grinding layer results from this. The higher non-productive times reduce the productivity of the grinding process and, in conjunction with the shorter lifetime of the grinding tool, thus increase the costs per work piece. It has already been shown that load-adapted grinding wheels can reduce uneven radial wear up to 50%. The adaptation of the wear behaviour to non-uniform engagement conditions causes non-uniform radial wear to occur again under uniform engagement conditions. Uniform engagement conditions occur during grinding wheel sharpening. Therefore, the present study investigates the influence of sharpening on the grinding tool topography. For this purpose, sharpening tests are carried out on four differently graded grinding wheels. For comparability, the tests are also carried out on two non-graded grinding wheels. In the present work, the surface parameters are evaluated with regard to their suitability for analysing the sharpening condition of graded grinding wheels. The grain protrusion derived from this is subsequently used for evaluation. For this, a dependency on the grain concentration is proven and the grain protrusions are shown over the grinding wheel widths. From this, sharpening parameters are determined that enable reproducible sharpening of graded grinding wheels