arXiv subjects

Daniel Herber

Publications and source records attributed to Daniel Herber.

4 recordsLinked to original sources

arXiv2026

Modeling Stakeholders and Lifecycle Requirements of Marine Hydrokinetic Energy Systems

Marine hydrokinetic energy offers a promising solution to the growing demand for clean and reliable electricity. These systems can generate power from low-speed flowing water, and over a wide range of sites. This paper outlines a lifecycle-based framework for developing marine hydrokinetic systems. It emphasizes stakeholder needs, regulatory compliance, and site-specific factors critical to successful deployment. By integrating engineering, environmental, and economic viewpoints, this work provides a baseline and other considerations for advancing these technologies toward commercial viability. First, six quality attributes are listed, and then five general stakeholders, including the consumer, owner, government, energy distributor, and regulatory bodies. Next, a set of general requirements grouped into five categories is shown. Finally, several key design decisions are discussed. Much of this content is captured in a model using the Systems Modeling Language (SysML). Overall, this paper can serve as a baseline for marine hydrokinetic technology development and understanding. This content is not comprehensive; further work will be required to ensure specific site and technology considerations are accounted for. Keywords: marine hydrokinetic systems, system lifecycle, model-based systems engineering, requirements, design, product development, risk management

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arXiv2026

Multi-Criteria Integer Programming Model for Route Planning in an Off-Road Combat Environment

Route planning for military vehicles is a complex decision-making problem due to the simultaneous influence of environmental trafficability and tactical risks. This paper presents an optimization model that integrates soil trafficability and risk of enemy engagement into a decision-support model for planning activities in open terrain. Although a military application is the focus of this paper, other use cases include wildfire response, agricultural operations, and off-road vehicle recreation. The routing problem is formulated as a minimum cost mixed-integer linear program over a discretized representation of the operational environment. Each node represents a location and is connected by arcs to adjacent nodes whose traversal incurs a cost derived from a composite risk function that accounts for soil strength and the proximity to known enemy activity and prior convoy routes. Environmental inputs required for evaluating soil strength are obtained by integrating external models, which estimate spatial variations in the rating cone index (RCI) across the terrain. The model is evaluated through a case study conducted at a location in northern Colorado using fine-resolution environmental data and simulated tactical conditions. Scenario analyses demonstrate how variations in risk weighting, vehicle mobility characteristics, and operational conditions influence route geometry and mission risk. The objective function values achieved varied by five orders of magnitude based on the coefficients assigned to the terms in the cost function and the vehicle properties of the scenario. The results illustrate the capability of the proposed framework to quantify trade-offs between environmental mobility constraints and tactical considerations.

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arXiv2024

Using Hybrid System Dynamics and Discrete Event Simulations to Identify High Leverage Targets for Process Improvement in a Skill-based Organizational Structure

This paper is based on a case study of an IT organization in a large, US-based healthcare provider, and develops simluation models to identify areas for performance improvement. These organizations are often grouped into departments by technical skill and support both operational work (tickets) and project work (tasks) of various priorities. From a practical standpoint, resource managers and staff regularly manage all work as queued and assign / complete it based on the priorities of the day. Using project and operational metrics from the case study organization, the hybrid model using both system dynamics and discrete event simulation developed through this research depicts the flow of work through a skill-based team as well as many of the key factors that influence that workflow, both positive and negative. Experience indicates that the interaction between project and operational work -- as well as between teams with differing skills -- entangles work queues and wait times within those queues in a way that rapidly scales in complexity as the number of interacting individuals and teams increases. Results from model simulation bear out this intuition. Scaling the models to accommodate multiple teams is a topic of future research.

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arXiv2023

Open-Loop Control Co-Design of Semisubmersible Floating Offshore Wind Turbines using Linear Parameter-Varying Models

This paper discusses a framework to design elements of the plant and control systems for floating offshore wind turbines in an integrated manner using linear parameter-varying models. Multiple linearized models derived from aeroelastic simulation software in different operating regions characterized by the incoming wind speed are combined to construct an approximate low-fidelity model of the system. The combined model is then used to generate open-loop, optimal control trajectories as part of a nested control co-design strategy that explores the system's power production and stability using the platform pitch tilt as a proxy in the context of crucial plant and control design decisions. The radial distance between the central and outer columns and the diameter of the outer columns of the semisubmersible platform are the plant design variables. The platform stability and power production are studied for different plant design decisions. The effect of plant decisions on subsequent power production and stability response of the floating wind turbine is quantified in terms of the levelized cost of energy. The results show that the inner-loop constraints and the plant design decisions affect the turbine's power and, subsequently, the cost of the system.

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