Ko Yamamoto, Kyosuke Ishibashi, Hiroki Ishikawa
et al.
This paper presents a design methodology of a hydraulically-driven soft robotic gripper for grasping a large and heavy object -- approximately 10 - 20 kg with 20 - 30 cm diameter. Most existing soft grippers are pneumatically actuated with several hundred kPa pressure, and cannot generate output force sufficient for such a large and heavy object. Instead of pneumatic actuation, hydraulic actuation has a potential to generate much larger power by several MPa pressure. In this study, we develop a hydraulically-driven soft gripper, in which its basic design parameters are determined based on a mathematical model that represents the relationship among the driving pressure, bending angle, object mass and grasping force. Moreover, we selected materials suitable for grasping a heavier object, based on the finite element analysis result of the detailed design. We report experimental results on a 20 kg object grasping and closed-loop control of the finger bending angle.
This chapter provides an overview of the application of hydraulics to flood hazard mapping in Japan. It explains the methods used to produce two types of flood hazard maps and highlights issues for further investigation, such as how to incorporate the process of levee collapse expansion in the vertical direction into modeling. It also provides evidence that flood hazard mapping is reliable in elucidating potential harm. Furthermore, it identifies problems with evacuation despite the provision of flood hazard maps. The purpose is to share information and serve as a call for new developments in flood hazard mapping. The information provided in this chapter can help young researchers and engineers to get a quick start in flood hazard mapping. At the same time, it can serve as an inspiration for more experienced researchers to pursue further in-depth studies.
As water distribution networks (WDNs) become increasingly connected with digital infrastructures, they face greater exposure to cyberattacks that threaten their operational integrity. Stealthy False Data Injection Attacks (SFDIAs) are particularly concerning, as they manipulate sensor data to compromise system operations while avoiding detection. While existing studies have focused on either detection methods or specific attack formulations, the relationship between attack sophistication, system knowledge requirements, and achievable impact remains unexplored. This paper presents a systematic analysis of sensor attacks against WDNs, investigating different combinations of physical constraints, state monitoring requirements, and intrusion detection evasion conditions. We propose several attack formulations that range from tailored strategies satisfying both physical and detection constraints to simpler measurement manipulations. The proposed attacks are simple and local -- requiring knowledge only of targeted sensors and their hydraulic connections -- making them scalable and practical. Through case studies on Net1 and Net3 benchmark networks, we demonstrate how these attacks can persistently increase operational costs and alter water flows while remaining undetected by monitoring systems for extended periods. The analysis provides utilities with insights for vulnerability assessment and motivates the development of protection strategies that combine physical and statistical security mechanisms.
Songjiang Lai, Tsun-Hin Cheung, Ka-Chun Fung
et al.
In this paper, we introduce Technical-Embeddings, a novel framework designed to optimize semantic retrieval in technical documentation, with applications in both hardware and software development. Our approach addresses the challenges of understanding and retrieving complex technical content by leveraging the capabilities of Large Language Models (LLMs). First, we enhance user queries by generating expanded representations that better capture user intent and improve dataset diversity, thereby enriching the fine-tuning process for embedding models. Second, we apply summary extraction techniques to encode essential contextual information, refining the representation of technical documents. To further enhance retrieval performance, we fine-tune a bi-encoder BERT model using soft prompting, incorporating separate learning parameters for queries and document context to capture fine-grained semantic nuances. We evaluate our approach on two public datasets, RAG-EDA and Rust-Docs-QA, demonstrating that Technical-Embeddings significantly outperforms baseline models in both precision and recall. Our findings highlight the effectiveness of integrating query expansion and contextual summarization to enhance information access and comprehension in technical domains. This work advances the state of Retrieval-Augmented Generation (RAG) systems, offering new avenues for efficient and accurate technical document retrieval in engineering and product development workflows.
Recent years have seen a significant interest in using phase field approaches to model hydraulic fracture, so as to optimise a process that is key to industries such as petroleum engineering, mining and geothermal energy extraction. Here, we present a novel theoretical and computational phase field framework to simulate hydraulic fracture. The framework is general and versatile, in that it allows for improved treatments of the coupling between fluid flow and the phase field, and encompasses a universal description of the fracture driving force. Among others, this allows us to bring two innovations to the phase field hydraulic fracture community: (i) a new hybrid coupling approach to handle the fracture-fluid flow interplay, offering enhanced accuracy and flexibility; and (ii) a Drucker-Prager-based strain energy decomposition, extending the simulation of hydraulic fracture to materials exhibiting asymmetric tension-compression fracture behaviour (such as shale rocks) and enabling the prediction of geomechanical phenomena such as fault reactivation and stick-slip behaviour. Four case studies are addressed to illustrate these additional modelling capabilities and bring insight into permeability coupling, cracking behaviour, and multiaxial conditions in hydraulic fracturing simulations. The codes developed are made freely available to the community and can be downloaded from {https://mechmat.web.ox.ac.uk/
Landslides significantly impact carbon dynamics across global regions, yet the long-term vegetation ecosystem net carbon effect from post-earthquake landslides remains unclear. To address this gap, this study focuses on the 2008 Wenchuan earthquake in Sichuan, China. Using landslide inventories and satellite data, we applied the Seasonal Autoregressive Integrated Moving Average Model (SARIMA) model and Bayesian change-point detection to examine long-term effects of post-earthquake landslides on vegetation ecosystem net carbon uptake (ENCU). For the restored areas, the multi-year total vegetation ecosystem net carbon loss (ENCL) was calculated for different landslide-prone areas. Subsequently, the Random Forest Regression Model and Structural Equation Model were used to explore the environmental drivers of ENCL. A substantial decline in ENCU was observed in the post-earthquake, with a 17.40 % reduction noted in May 2008. By 2019, only 45 out of 86 affected areas recovered to pre-earthquake ENCU levels, with 18 areas surpassing their initial levels. Recovery times for most landslides ranged from 8 to 11 years. From 2008 to 2019, the total ENCL across various landslide-affected areas primarily ranged from 5000 to 20,000 gC m−2. Precipitation emerged as a key driver of ENCL, while landscape fragmentation hindered recovery. These findings underscore the need for sustainable post-earthquake land management to maintain carbon balance, offering new insights into how seismic events influence global carbon cycles.
AI progress is creating a growing range of risks and opportunities, but it is often unclear how they should be navigated. In many cases, the barriers and uncertainties faced are at least partly technical. Technical AI governance, referring to technical analysis and tools for supporting the effective governance of AI, seeks to address such challenges. It can help to (a) identify areas where intervention is needed, (b) identify and assess the efficacy of potential governance actions, and (c) enhance governance options by designing mechanisms for enforcement, incentivization, or compliance. In this paper, we explain what technical AI governance is, why it is important, and present a taxonomy and incomplete catalog of its open problems. This paper is intended as a resource for technical researchers or research funders looking to contribute to AI governance.
Los lagos y lagunas cumplen diversas funciones vitales para los ecosistemas y el desarrollo socioeconómico de las poblaciones cercanas a ellos. La laguna de Ayarza está ubicada a una distancia de 108.00 kilómetros de la ciudad capital, entre los municipios de Casillas y San Rafael Las Flores, en el departamento de Santa Rosa, Guatemala. Esta laguna se considera un cuerpo léntico de tamaño relativamente pequeño, razón por la cual no posee información que permita definir sus características y por ende imposibilita conocer su condición actual y definir planes a futuro. En esta investigación se buscó definir la profundidad y secciones de la laguna a través de su batimetría. Se determinó que la longitud de la laguna es de 5.78 kilómetros con un ancho de 3.73 kilómetros y perímetro de 20.00 kilómetros, ocupando un área de 13.80 kilómetros cuadrados en época de estiaje (febrero-marzo) del año 2015. La metodología utilizada consistió en procedimientos de campo como levantamiento topográfico utilizando un GPS, así con el trazo de una cuadricula en toda su superficie para realizar las mediciones de profundidad con ecosonda. Con la información recabada se trabajó en un software para determinar las curvas de nivel y secciones de la laguna evidenciándose que existen zonas en el centro de la laguna que superan los 400 metros de profundidad. Esta información permite tener una línea base para futuros trabajos de investigación que permitan establecer las condiciones eutróficas de la laguna, y/o acciones a realizar como por ejemplo dragados.
LIU Chunyuan1, XIAO Jun2, CHEN Xiaosong1, SUN Peidong1, XING Mian1
Miniaturization of nuclear energy systems will be a promising direction for nuclear industry development in the future, in which micro lead-cooled fast reactors (LFRs) are a type of technical route in relevant. During the R&D of micro LFRs, transient thermal-hydraulic safety analysis is one of the important research fields, which can not only verify the safety of the design, but also provide optimization reference for the follow-up design of the reactor. SMILE is a megawatt-level micro LFR with high safety and compactness, designed by State Power Investment Corporation Research Institute. For SMILE, pure lead is applied as the coolant. The fuel adopts UO2, while the cladding and structural materials use independently developed wide oxygen-controlling corrosion-resistant materials, which can simplify or even omit complex oxygen measurement and control systems. Its core is designed for long-life without refueling, eliminating complex refueling devices. Its reactivity is controlled by external drums. The main system employs a compact design scheme, using a pool-type integrated compact layout, with an integrated main pump and main heat exchanger structure. The secondary system uses a compact water steam cycle or S-CO2 Brayton cycle, along with a non-passive residual heat removal system. Due to the advanced concepts of lead-cooled fast reactor designs, there has not been a mature unified thermal-hydraulic safety criterion. Based on SMILE’s design characteristics and a literature review, some key parameters’ performance criteria for thermal-hydraulic safety are proposed, including flow velocity of the coolant, coolant temperature, temperature of the fuel cladding, etc. During reactor operation, various abnormal events deviating from normal operating ranges may occur, potentially leading to accident conditions. For SMILE, unprotected loss of flow (ULOF), unprotected transient over-power (UTOP), unprotected loss of heat sink (ULOHS), were deeply investigated in the present paper. ATHLET (analysis of thermal-hydraulics of leaks and transients) is a best-estimate one-dimensional system safety analysis program developed by Gesellschaft für Anlagen-und Reaktorsicherheit (GRS), which is applicable to analyzing various reactor types such as pressurized water reactors, boiling water reactors, graphite-water-cooled reactors, and CANDU reactors, for both benchmark and beyond-benchmark accident analyses. With the development of Gen-Ⅳ nuclear energy systems, GRS has extended the applicability of ATHLET, incorporating properties of metals and liquid metal heat transfer relationships, enabling to be applied for analyzing the thermal-hydraulic characteristics of lead-cooled fast reactors. Through analysis, it is found that under normal conditions, the results obtained from ATHLET are in good agreement with the design values, thus AHTLET program is capable of analyzing the transient features of SMILE. Under typical unprotected transient accident conditions, SMILE shows a good natural circulation performance and thermal characteristics, in particular given it inherent safety features. However, according to simulation results, in the event of an ULOF transient accident, the cladding temperature of the fuel exceeds the maximum temperature limit, which could potentially threaten the reactor’s safe operation. Therefore, in the future high-temperature corrosion-resistant materials will be developed, for eliminating or mitigating its impact on the system’s safe operation.
Cognitive biases exert a significant influence on human thinking and decision-making. In order to identify how they influence the occurrence of architectural technical debt, a series of semi-structured interviews with software architects was performed. The results show which classes of architectural technical debt originate from cognitive biases, and reveal the antecedents of technical debt items (classes) through biases. This way, we analysed how and when cognitive biases lead to the creation of technical debt. We also identified a set of debiasing techniques that can be used in order to prevent the negative influence of cognitive biases. The observations of the role of organisational culture in the avoidance of inadvertent technical debt throw a new light on that issue.
Inverse Uncertainty Quantification (IUQ) method has been widely used to quantify the uncertainty of Physical Model Parameters (PMPs) in nuclear Thermal Hydraulics (TH) systems. This paper introduces a novel hierarchical Bayesian model which aims to mitigate two existing challenges in IUQ: the high variability of PMPs under varying experimental conditions, and unknown model discrepancies or outliers causing over-fitting issues. The proposed hierarchical model is compared with the conventional single-level Bayesian model using TRACE code and the measured void fraction data in the BFBT benchmark. A Hamiltonian Monte Carlo Method - No U-Turn Sampler (NUTS) is used for posterior sampling. The results demonstrate the effectiveness of the proposed hierarchical model in providing better estimates of the posterior distributions of PMPs and being less prone to over-fitting. The proposed method also demonstrates a promising approach for generalizing IUQ to larger databases with broad ranges of experimental conditions.
In this article, I will explore the nature of interference in translation, especially in technical and scientific texts, using a descriptivist approach. I will have a brief overview of the historical excursion of interference in technical and scientific translation. My aim is to explain this phenomenon and its causes with all its paradoxes, instead of simply condemning it as an example of supposedly bad translation. Thus, I will focus on its status in the bibliography of translation, on the motives for and consequences of interference in specialized translation, as well as on the nature of the arguments given for and against this phenomenon. Therefore the relationship between different societies has always been possible with the act of translation. When civilizations are examined throughout history, it is seen that the dissemination of knowledge among different societies has been achieved by translation. These societies have often become aware of the advancements in technology and science by means of translation. Therefore; translation becomes very significant in technical contact between societies and humans. Since the translation of technical texts is the preliminary scope of this thesis, it will be beneficial to have a brief look at the history of technical translation in the world.
This paper provides a novel surface design and experimental evaluation of a super-twisting algorithm (STA) based control for hydraulic cylinder actuators. The proposed integral sliding surface allows to track a sufficiently smooth reference without using the velocity state which is hardly accessible in the noisy hydraulic systems. A design methodology based on LMI's is given, and the STA gains are designed to be adjusted by only one free parameter. The feasibility and effectiveness of the proposed control method are shown on a standard hydraulic test bench with one linear degree of freedom and passive load, where a typical motion profile is tracked with a bounded average error below 1 % from the total drive effective output.
Eriks Klotins, Michael Unterkalmsteiner, Panagiota Chatzipetrou
et al.
Context: Software start-ups are young companies aiming to build and market software-intensive products fast with little resources. Aiming to accelerate time-to-market, start-ups often opt for ad-hoc engineering practices, make shortcuts in product engineering, and accumulate technical debt. Objective: In this paper we explore to what extent precedents, dimensions and outcomes associated with technical debt are prevalent in start-ups. Method: We apply a case survey method to identify aspects of technical debt and contextual information characterizing the engineering context in start-ups. Results: By analyzing responses from 86 start-up cases we found that start-ups accumulate most technical debt in the testing dimension, despite attempts to automate testing. Furthermore, we found that start-up team size and experience is a leading precedent for accumulating technical debt: larger teams face more challenges in keeping the debt under control. Conclusions: This study highlights the necessity to monitor levels of technical debt and to preemptively introduce practices to keep the debt under control. Adding more people to an already difficult to maintain product could amplify other precedents, such as resource shortages, communication issues and negatively affect decisions pertaining to the use of good engineering practices.
El afloramiento de Eichhornia crassipes es común en las lagunas de Olomega y El Jocotal, sin embargo, no existe una idea certera del comportamiento de la Eichhornia crassipes en ambas lagunas en época de sequía. En el presente estudio se analizó el fenómeno mediante el uso de sensores remotos, identificando primero los periodos de sequía a través del cálculo del índice estandarizado de precipitación y evapotranspiración con los datos de precipitación mensual, temperatura máxima mensual y temperatura mínima mensual, durante los años del 2012 al 2021 en la laguna de Olomega y El Jocotal. Posteriormente, con el uso de imágenes satelitales tomadas de Landsat para los periodos de sequía seleccionados, se calcularon los índices de vegetación de diferencia normalizado para la obtención de las áreas del espejo de agua sin y con cobertura de Eichhornia crassipes para cada laguna. Finalmente, con los sistemas de información geográficos se realizaron diferentes matrices de transición para evaluar el comportamiento de la Eichhornia crassipes durante los periodos de sequía, así como del espejo de agua si afloramiento. Los resultados obtenidos mostraron que para ambas lagunas un mayor índice de sequía no es sinónimo de mayor afloramiento de Eichhornia crassipes, por lo que la sequía no tiene un impacto en la presencia de Eichhornia crassipes, sin embargo, el espejo de agua sin afloramiento si se ve afectado en los periodos de sequía.
Las investigaciones que se realizan sobre el tratamiento de aguas grises buscan aportar a la sostenibilidad y la conservación de los recursos hídricos. En esta investigación se evaluó un sistema económico de tratamiento de aguas grises mediante un prototipo de cuatro barriles, basado en materiales reciclados y de bajo costo, inspirado en el "Barrel System" de Jordania utilizado en el año 2007. El sistema incluye cuatro compartimentos: uno para eliminación de grasas, otro con grava en su interior, y dos con arena antracita. El estudio utilizó aguas grises de una lavadora y un lavatrastos, excluyendo otras fuentes debido a limitaciones hidráulicas, de espacio y costo. Para evaluar la eficiencia de remoción de sólidos sedimentables, demanda química de oxígeno (DQO), demanda bioquímica de oxígeno (DBO5), potencial de hidrógeno (pH) y fósforo total (Pt) se utilizó el método 1060B de los Métodos Normalizados para el análisis de Aguas Potables y Residuales. El análisis estadístico se trabajó con un 95% de confianza. Los resultados mostraron una remoción promedio del 54% para la demanda bioquímica de oxígeno, 48% para la demanda química de oxígeno. Se identificaron diferencias significativas entre los valores iniciales de sólidos sedimentables y fósforo total con tendencia a reducirse y el potencial de hidrógeno tuvo una reducción significativa del 9% de su valor inicial promedio. Este sistema de filtración múltiple presenta una propuesta viable para el tratamiento de agua residual a nivel domiciliar.
Es un honor presentar una nueva edición de la revista científica "Agua, Saneamiento y Ambiente" (ASA), una iniciativa que ha estado iluminando el panorama de la investigación en la región desde su fundación en 2004. ASA, publicada por la Escuela Regional de Ingeniería Sanitaria y Recursos Hidráulicos (ERIS) de la Facultad de Ingeniería de la Universidad de San Carlos de Guatemala, ha superado barreras y se ha consolidado como una plataforma abierta para científicos de toda América Latina.
Desde su primera versión impresa, ASA ya contaba con la indización en el directorio y catalogo 1.0 de Latindex, y a partir del 2022 ASA ha contado con una indización en el catálogo Latindex 2.0, lo cual ha permitido que ofrezca un espacio inclusivo donde investigadores de diversos campos relacionados con la gestión del recurso hídrico y diversas procedencias pueden compartir los frutos de su trabajo, independientemente del tamaño de la investigación, ubicación geográfica, situación económica y otros factores. Esta edición, como testimonio de nuestro compromiso, destaca contribuciones significativas de investigadores de Guatemala, El Salvador, Nicaragua y Panamá.
La presente edición de la revista ASA es un testimonio del compromiso continuo de la revista con la promoción de investigaciones científicas rigurosas y relevantes para nuestra región. Agradecemos a todos los autores, revisores y colaboradores que han contribuido a hacer de ASA una plataforma clave para la divulgación científica en América Latina. Esperamos que disfruten de esta entrega y que continúen siendo parte activa de nuestra comunidad científica.
The article presents a process control system for sorting agricultural products. The technological process of sorting is described, the composition of the system is indicated, the sorting algorithm is developed. ProgramLab software was used as the modeling environment. Color and weight were selected as sorting criteria. The parameters at the input of the control object, which have the greatest influence on the process were selected. The output parameters were the conveyor speed and the final position of the sorting object. A scheme of cause-and-effect relationships of the sorting process is obtained. A block diagram of the sorting process has been developed. A mathematical model for calculating the speed of a conveyor depending on the distance between the robotic arm and the conveyor, as well as between the robotic arm and the parts unloading points was obtained. A 3d model of the sorting process has been developed. Three basic scenarios for the location of places for unloading agricultural products are considered. The introduction of the developed system will help reduce number of rejects during sorting, increase the efficiency of the sorting process and improve economic performance. Improving the sorting process will help reduce equipment wear and extend equipment life.
The purpose of this Coastal and Hydraulics Engineering technical note (CHETN) is to specify the software requirements, architecture, and detailed design for the DataSwitch Data Sweeper (DS)² application. This document is designed for the software developers maintaining (DS)2 and is intended to aid these developers in understanding its architecture and underlying functionality.
This Coastal and Hydraulics Engineering technical note (CHETN) presents preliminary results from a series of tests conducted at the US Army Engineer Research and Development Center (ERDC), Coastal and Hydraulics Laboratory (CHL), Field Research Facility (FRF), in Duck, North Carolina, to explore the capabilities and limitations of the GSFL16K Flash Lidar Camera in nearshore science and engineering applications. The document summarizes the spatial coverage and density of data collected in three deployment scenarios and with a range of tuning parameters and provides guidance for future deployments and data-collection efforts.