Fine-tuning property domain weighting factors and the objective function in force-field parameter optimization

Force field (FF) based molecular modeling is an often used method to investigate and study structural and dynamic properties of (bio-)chemical substances and systems. When such a system is modeled or refined, the force-field parameters need to be adjusted. This force-field parameter optimization can be a tedious task and is always a trade-off in terms of errors regarding the targeted properties. To better control the balance of various properties’ errors, in this study we introduce weighting factors for the optimization objectives. Different weighting strategies are compared to fine-tune the balance between bulk-phase density and relative conformational energies (RCE), using n-octane as a representative system. Additionally, a non-linear projection of the individual property-specific parts of the optimized loss function is deployed to further improve the balance between them. The results show that the combined error for the reproduction of the properties targeted in this optimization is reduced. Furthermore, the transferability of the force field parameters (FFParams) to chemically similar systems is increased. One interesting outcome is a large variety in the resulting optimized FFParams and corresponding errors, suggesting that the optimization landscape is multi-modal and very dependent on the weighting factor setup. We conclude that adjusting the weighting factors can be a very important feature to lower the overall error in the FF optimization procedure, giving researchers the possibility to fine-tune their FFs

Parameter-Efficient Fine-Tuning of Vision Foundation Model for Forest Floor Segmentation from UAV Imagery

Unmanned Aerial Vehicles (UAVs) are increasingly used for reforestation and forest monitoring, including seed dispersal in hard-to-reach terrains. However, a detailed understanding of the forest floor remains a challenge due to high natural variability, quickly changing environmental parameters, and ambiguous annotations due to unclear definitions. To address this issue, we adapt the Segment Anything Model (SAM), a vision foundation model with strong generalization capabilities, to segment forest floor objects such as tree stumps, vegetation, and woody debris. To this end, we employ parameter-efficient fine-tuning (PEFT) to fine-tune a small subset of additional model parameters while keeping the original weights fixed. We adjust SAM's mask decoder to generate masks corresponding to our dataset categories, allowing for automatic segmentation without manual prompting. Our results show that the adapter-based PEFT method achieves the highest mean intersection over union (mIoU), while Low-rank Adaptation (LoRA), with fewer parameters, offers a lightweight alternative for resource-constrained UAV platforms

Determinants of institutional change towards a sustainable energy transition in Ghana: A political economy analysis of solar photovoltaics

The transition to sustainable energy systems does not only entail changes to existing technologies or infrastructure. It also involves significant changes in a country's institutional frameworks that are rarely examined. Anchored in institutional analysis, this paper analyses the political economy factors influencing institutional change towards a sustainable energy transition in Ghana, with a particular focus on solar photovoltaics (PVs). The findings indicate that even though progress has been slow moving and incremental, the process of institutional change is cumulative and constitutes a fundamental third-order change. Institutional legacies within the energy sector present strong but not prohibitive barriers to renewable energy adoption. Initially, the relatively homogenous nature of preferences among key actors facilitated the introduction of solar PV. However, conflicting interests among policymakers, who simultaneously support solar PVs and fossil-fuel agendas emerged during a later phase and undermined progress. The declining cost of solar PV systems over time has, nonetheless, provided new momentum for change. Environmental conditions or shocks exogeneous to the reform domain have had mixed effects on Solar PV adoption. While Ghana's numerous power crisis exposed the inadequacies of hydro and thermal sources and created an opportunity for solar PVs, the discovery of oil and gas resources in 2007 significantly slowed change. Although international concerns about climate change and sustainable development have provided some momentum for policy change, perceived injustices in international relations between countries in the Global South and those in the Global North tend to slow the transition process down

Biopolymer-Based Vehicles for Drug Encapsulation

Biopolymers are increasingly used to design drug delivery systems (DDSs), which incorporate therapeutic agents to deliver drugs precisely to the diseased sites with minimal side effects. An ideal DDS targets and controls drug release, protecting drugs from breakdown during transport. Due to their biocompatibility and biodegradability, the DDS made of biopolymers acts as a drug vehicle to reduce the side effects in the body [1]. In this preliminary work, chitosan hydrogels were prepared using 1,3,5-benzene tricarboxylic acid (BTC) as a crosslinker. In addition, the release behavior of the hydrophobic dye (Rhodamine B) from the chitosan hydrogels was examined. The dye was used in this work to visually track and quantify the loading and release behavior

A 33-year diagnostic odyssey in an Ashkenazi Jewish patient with Aicardi-Goutières syndrome

The critical need for awareness and genetic testing of the SAMHD1 deletion in Ashkenazi Jewish patients is highlighted owing to its relatively high carrier frequency. Early detection can prevent severe disease complications through targeted therapy

Geschäftsprozesse analysieren und optimieren: Praxistools zur Analyse, Optimierung und Controlling von Arbeitsabläufen

Die 3. Auflage dieses Buchs zeigt konkret auf, was Geschäftsprozessmanagement ist und wie man es nutzen kann. Hierzu werden die zentralen Aspekte erklärt und praxistaugliche Tools anhand von Beispielen vorgestellt. Erleichtern Sie sich die tägliche Praxis der Analyse und Optimierung von Geschäftsprozessen

Remote Heart Rate Detection and Presentation Attack Detection Using Time-of-Flight Cameras: A Feasibility Study

Modern biometric systems incorporate Presentation Attack Detection (PAD) mechanisms as elementary part to guard against spoofing. One effective approach is the detection of physiological liveness signals, such as heart rate. Our study explores the feasibility of using a 3D Time-of-Flight (ToF) camera to measure heart rate as a PAD method

Informationssicherheitsmanagementsysteme aus einer systemtheoretischen Sicht

Die Thesis befasst sich mit der Darstellung der Systemtheorie Niklas Luhmanns als theoretisches Fundament zur Erforschung von Informationssicherheitsmanagementsystemen (ISMS). Anhand von verschiedenen Anwendungsfällen stellt diese Arbeit die Vorzüge der Theorie Luhmanns gegenüber Keiner oder anderen Theorien dar