83 research outputs found
Imaging and non-imaging illumination of a DLP for high resolution headlamps
Matrix-LED systems offer different functionalities to increase road safety, e.g. glare-free high beam and marking light. Shortly after their introduction, efforts have been made to increase the amount of pixels. One of the results is the EVIYOS LED consisting of 1024 individually controllable pixels, which practically set the stage for pixel light systems. Current efforts to implement high-resolution pixel light systems are focused towards the exploration of an efficient light source in combination with the use of spatial light modulators. One approach to implement high-resolution pixel light systems is the use of LED arrays as a light source to illuminate a DLP. Unlike video projectors which require a homogeneous illumination of the DLP in order to obtain a homogeneous projection, headlamps require an inhomogeneous light distribution with high illuminance in the center. In order to receive a high system efficiency preforming the desired illuminance onto the active area of the modulator is advantageous. To further increase the systems efficiency an imaging illumination of the DLP, where the images of the emission surfaces of the LEDs are superposed onto the active area of the DLP, is worthwhile. In this paper, concepts for imaging and non-imaging illumination strategies of a DLP for high resolution headlamps will be introduced. For both illumination strategies the most promising concept will be selected to set up an optical system to illuminate a DLP. The paper concludes with a comparative analysis of the imaging and non-imaging optical system with regards to the system architecture and system efficiency
Hybrid Ray Tracing
Nowadays optical systems are predominantly developed using conventional ray tracing methods such as sequential and non-sequential ray tracing. Sequential ray tracing is used in particular to design and optimize imaging systems. However, non-sequential ray tracing allows to take into account the resulting absorption losses and Fresnel reflections within an optical system and therefore enabling realistic predictions about the efficiency of optical systems.
The increasing complexity of optical systems combined with the demand of high efficiency and high image quality leads to the fact that conventional methods reach their limits. This challenge can be met by implementing a hybrid ray tracing method. The objective here is to achieve an application-specific ratio between the imaging quality and the efficiency of the optical system.
This contribution introduces a tool for the development of highly efficient optical systems considering imaging quality using a hybrid ray tracing method. We will show how the efficiency determined in non-sequential ray tracing can be used in sequential ray tracing to optimize the optical system
Chinese Ethics: An Empirical Study of Idealism and Relativism
The purpose of this empirical study is to examine the relationships between ethical views of certain Chinese demographics and to consider different trends that may affect academic and business considerations in the future pertaining to East-West interaction. This study utilizes Forsythâs Ethics Position Questionnaire (EPQ) to assess the ethical views of 401 Chinese undergraduate students in a rural province of Central China. Regression analyses are applied to investigate the following hypotheses: In a new Chinese context, the EPQ is applicable for assessing the ethical views of Chinese undergraduate students in rural China. Rural Chinese undergraduate student EPQ results are demonstrative of, and, in view of prior studies, are predictive of changes in Chinese ethical considerations. Rural Chinese undergraduate student EPQ results reflect long held Eastern worldview approaches however, in view of prior studies, there is some increasing similarity with Western EPQ outcomes. The findings of this study support the acceptance of the first and third null hypotheses. The practical implications of this study include an understanding that China, though it is rapidly equating with Western levels of market technology and sophistication, continues to resist Western ideals and ethics. Rather, the blending of Western and Eastern principles will continue to evolve and the Chinese worldview will continue to be dominated by the goals and needs of the Chinese State in a reflection of the millennia old culture. The value of this study is that it updates data relating to Chinese ethical approaches in a fast-changing Chinese and global marketplace. Secondly, it clarifies the different considerations and approaches needed when Westerners are dealing with Chinese counterparts in academia and/or business. Lastly, it posits current and future trends likely to affect East-West relationships in these realms
Tailoring the V-Model for Optics: A Methodology for Optomechatronic Systems
The integration of optical technologies into once purely mechatronic systems enables innovative functions, but simultaneously increases the complexity of previous mechatronic system development. Therefore, a process has been elaborated to develop these so-called optomechatronic systems by Knöchelmann at the Institute of Product Development at Leibniz University Hanover, which is based on the V-Model of VDI 2206 and can be applied to various fields of application. For a target-oriented development in a specific product context and for systems with competing main requirements, detailing and adapting the process is recommended. High-resolution lighting systems are one of them, where requirements for high optical efficiency and image quality lead to a conflict of objectives. Focusing on the optics domain, Ley elaborated methods for the preliminary and detailed design of high-resolution lighting systems to address the aforementioned conflict of objectives. This contribution focuses on the integration of Leyâs design methods into Knöchelmannâs process model within the phases of system design and domain-specific design, allowing us to analyze the impact of the system design on the fulfillment of main requirements to achieve an optimal solution of the conflict of objectives. To illustrate this, the integrated process model is described using an example from automotive lighting technology
Potentials and challenges of additive manufacturing using highly transparent silicone materials
The research in additive manufacturing using highly transparent silicone for optical applications is still in its early stages. This contribution is aiming to investigate potentials and challenges in additive manufacturing using silicone and to identify a suitable manufacturing concept to fabricate highly transparent optical elements.Funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) in Germanyâs Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453) and funded by EFRE - Nbank within the project âGROTESK - Generative Fertigung optischer, ther-maler und struktureller Komponentenâ (ZW6-85018307, ZW6-85017815, ZW6-85017913, ZW6-85018048)
Requirements for Automotive LiDAR Systems
Light detection and ranging (LiDAR) are fundamental sensors that help driving tasks for autonomous driving at various levels. Commercially available systems come in different specialized design schemes and involve plenty of specifications. In the literature, there are insufficient representations of the technical requirements for LiDAR systems in the automotive context, such as range, detection quality, resolving power, field of view, and eye safety. For this reason, the requirements above require to be derived based on ADAS functions. The requirements for various key LiDAR metrics, including detection range, field of view, angular resolution, and laser safety, are analyzed in this paper. LiDAR systems are available with various radiation patterns that significantly impact on detection range. Therefore, the detection range under various radiation patterns is firstly investigated in this paper. Based on ADAS functions, the required detection range and field of view for LiDAR systems are examined, taking into account various travel speeds to avoid collision and the coverage of the entire lane width. Furthermore, the angular resolution limits are obtained utilizing the KITTI dataset and exemplary 3D detection algorithms. Finally, the maximum detection ranges for the different radiation patterns are compared under the consideration of derived requirements and laser safety
Identification of tightly regulated groups of genes during Drosophila melanogaster embryogenesis
Time-series analysis of whole-genome expression data during Drosophila melanogaster development indicates that up to 86% of its genes change their relative transcript level during embryogenesis. By applying conservative filtering criteria and requiring âsharp' transcript changes, we identified 1534 maternal genes, 792 transient zygotic genes, and 1053 genes whose transcript levels increase during embryogenesis. Each of these three categories is dominated by groups of genes where all transcript levels increase and/or decrease at similar times, suggesting a common mode of regulation. For example, 34% of the transiently expressed genes fall into three groups, with increased transcript levels between 2.5â12, 11â20, and 15â20 h of development, respectively. We highlight common and distinctive functional features of these expression groups and identify a coupling between downregulation of transcript levels and targeted protein degradation. By mapping the groups to the protein network, we also predict and experimentally confirm new functional associations
The generalisability of randomised clinical trials : an interim external validity analysis of the ongoing SENOMAC trial in sentinel lymph node-positive breast cancer
Purpose None of the key randomised trials on the omission of axillary lymph node dissection (ALND) in sentinel lymph-positive breast cancer have reported external validity, even though results indicate selection bias. Our aim was to assess the external validity of the ongoing randomised SENOMAC trial by comparing characteristics of Swedish SENOMAC trial participants with non-included eligible patients registered in the Swedish National Breast Cancer Register (NKBC). Methods In the ongoing non-inferiority European SENOMAC trial, clinically node-negative cT1-T3 breast cancer patients with up to two sentinel lymph node macrometastases are randomised to undergo completion ALND or not. Both breast-conserving surgery and mastectomy are eligible interventions. Data from NKBC were extracted for the years 2016 and 2017, and patient and tumour characteristics compared with Swedish trial participants from the same years. Results Overall, 306 NKBC cases from non-participating and 847 NKBC cases from participating sites (excluding SENOMAC participants) were compared with 463 SENOMAC trial participants. Patients belonging to the middle age groups (p = 0.015), with smaller tumours (p = 0.013) treated by breast-conserving therapy (50.3 versus 47.1 versus 65.2%, p < 0.001) and less nodal tumour burden (only 1 macrometastasis in 78.8 versus 79.9 versus 87.3%, p = 0.001) were over-represented in the trial population. Time trends indicated, however, that differences may be mitigated over time. Conclusions This interim external validity analysis specifically addresses selection mechanisms during an ongoing trial, potentially increasing generalisability by the time full accrual is reached. Similar validity checks should be an integral part of prospective clinical trials. Trial registration: NCT 02240472, retrospective registration date September 14, 2015 after trial initiation on January 31, 2015Peer reviewe
Advancing Intraoperative Assessment of Urethral Stricture Anatomic Variation: a Prospective Proof-of-concept Study
INTRODUCTION
Urethral strictures, particularly those refractory to endoscopic interventions, are commonly treated through open urethroplasty. However, predicting recurrence in homogeneous patient populations remains challenging.
METHODS
To address this, we developed an intraoperative urethral stricture assessment tool aiming to identify comprehensive risk predictors. The assessment includes detailed parameters on stricture location, length, urethral bed width, spongiosum thickness, obliteration grade, and spongiofibrosis extension. The tool was prospectively implemented in 106 men with anterior one-stage augmentation urethroplasty 04/2020 to 10/2021.
RESULTS
An intraoperative granular assessment of intricate stricture characteristics is feasible. Comparative analyses revealed significant differences between bulbar and penile strictures. Bulbar strictures exhibited wider urethral beds and thicker spongiosum compared to penile strictures (all P<0.001). The assessment showed marked variations in the degree of obliteration and spongiofibrosis extension.
CONCLUSION
Our tool aligns with efforts to standardize urethral surgery, providing insights into subtle disease intricacies and enabling comparisons between institutions. Notably, intraoperative assessment may surpass the limitations of preoperative imaging, emphasizing the necessity of intraoperative evaluation. While limitations include a single-institution study and limited sample size, future research aims to refine this tool and determine its impact on treatment strategies, potentially improving long-term outcomes for urethral strictures
eggNOG v3.0: orthologous groups covering 1133 organisms at 41 different taxonomic ranges
Orthologous relationships form the basis of most comparative genomic and metagenomic studies and are essential for proper phylogenetic and functional analyses. The third version of the eggNOG database (http://eggnog.embl.de) contains non-supervised orthologous groups constructed from 1133 organisms, doubling the number of genes with orthology assignment compared to eggNOG v2. The new release is the result of a number of improvements and expansions: (i) the underlying homology searches are now based on the SIMAP database; (ii) the orthologous groups have been extended to 41 levels of selected taxonomic ranges enabling much more fine-grained orthology assignments; and (iii) the newly designed web page is considerably faster with more functionality. In total, eggNOG v3 contains 721â801 orthologous groups, encompassing a total of 4â396â591 genes. Additionally, we updated 4873 and 4850 original COGs and KOGs, respectively, to include all 1133 organisms. At the universal level, covering all three domains of life, 101â208 orthologous groups are available, while the others are applicable at 40 more limited taxonomic ranges. Each group is amended by multiple sequence alignments and maximum-likelihood trees and broad functional descriptions are provided for 450â904 orthologous groups (62.5%
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