Grid Layout Research Articles

VADIS: A Visual Analytics Pipeline for Dynamic Document Representation and Information-Seeking.

In the biomedical domain, visualizing the document embeddings of an extensive corpus has been widely used in informationseeking tasks. However, three key challenges with existing visualizations make it difficult for clinicians to find information efficiently. First, the document embeddings used in these visualizations are generated statically by pretrained language models, which cannot adapt to the user's evolving interest. Second, existing document visualization techniques cannot effectively display how the documents are relevant to users' interest, making it difficult for users to identify the most pertinent information. Third, existing embedding generation and visualization processes suffer from a lack of interpretability, making it difficult to understand, trust and use the result for decision-making. In this paper, we present a novel visual analytics pipeline for user-driven document representation and iterative information seeking (VADIS). VADIS introduces a prompt-based attention model (PAM) that generates dynamic document embedding and document relevance adjusted to the user's query. To effectively visualize these two pieces of information, we design a new document map that leverages a circular grid layout to display documents based on both their relevance to the query and the semantic similarity. Additionally, to improve the interpretability, we introduce a corpus-level attention visualization method to improve the user's understanding of the model focus and to enable the users to identify potential oversight. This visualization, in turn, empowers users to refine, update and introduce new queries, thereby facilitating a dynamic and iterative information-seeking experience. We evaluated VADIS quantitatively and qualitatively on a real-world dataset of biomedical research papers to demonstrate its effectiveness.

Shear behavior of pre-damaged RC beams strengthened with UHPFRC-CFRP grid layer

Ultra-high performance fiber reinforced concrete (UHPFRC), incorporating recycled tyre fibers, and carbon fiber-reinforced polymer (CFRP) grid were utilized to strengthen the pre-damaged reinforced concrete beams caused by coupling action of sustained loads and marine environment. The failure modes, characteristic loads, deflection features, and strain behavior of the strengthened beams with various types of UHPFRC, thicknesses of UHPFRC layers, CFRP grid ratios, and CFRP grid layout angles were investigated. The results indicated that they exhibited the typical shear failure, and their characteristic loads increased by 102 %–205 % compared to the undamaged beam. By increasing the thickness of the UHPFRC layer and the CFRP grid ratio, and adopting 45° CFRP layout angle, the cracking stiffness, energy absorption capacity, and shear force sharing ability would be further improved, while adopting the UHPFRC incorporating recycled tyre fibers would decrease the ductility. Moreover, analytical models were developed to calculate the ultimate loads, manifesting reasonable accuracy.

Interplay of Size, Deformability, and Device Layout on Cell Transport in Microfluidics.

Microfluidics have been widely used for cell sorting and capture. In this work, numerical simulations of cell transport in microfluidic devices were studied considering cell sizes, deformability, and five different device designs. 
Among these five designs, deterministic lateral displacement device (DLD) and hyperuniform device (HU) performed better in promoting cell-micropost collision due to the continuously shifted micropost positions as compared with regular grid, staggered, and hexagonal layout designs. However, the grid and the hexagonal layouts showed best in differentiating cells by their size dependent velocity due to the size exclusion effect for cell transport in clear and straight paths in the flow direction. A systematic study of the velocity differentiation under different dimensionless groups was performed showing that the velocity difference is dominated by the micropost separation distance perpendicular to the direction of flow. Microfluidic experiments also confirmed the velocity differentiation results. The study can provide guiding principles for microfluidic design.

A comparison of differing organizational formats for teaching requesting skills to children with autism

The selection of high-tech AAC for children diagnosed with autism spectrum disorder can be a challenging process due to the vast array of options available. One of the decisions that clinicians need to make involves how vocabulary will be organized on the display. This study aimed to compare a visual scene display (VSD) with a grid display using a multiple-probe design across participants with an embedded adapted alternating treatment design. Four young children with autism spectrum disorder who were beginning communicators were recruited and taught to request preferred items using two display formats: VSD and grid layout on a mainstream tablet with an AAC app. Two of the participants achieved criterion with both displays, the other two participants failed to achieve criterion in either display. For all participants, progress was similar in both displays. The results are discussed through the lens of each participant’s characteristics with suggestions for clinical decision-making.

Integrated floating wind farm layout design and mooring system optimization to increase annual energy production

As we cluster wind turbines in wind farms to gain energy from sites with high wind speeds, wake losses occur within the wind farm. Wake loss is a term used to describe the lower energy production of a downwind turbine that is totally or partially in the wake of an upwind turbine. To decrease wake losses inside the wind farm, the wind farm’s layout is optimized. However, a variety of factors constrain the wind farm layout optimization, such as the size of the lease area relative to the number of turbines to be placed, or the shape of the lease area. Therefore, many wind farms end up with a regular grid layout, such as the Horns Rev 1 wind farm in the North Sea. The ability of a floating offshore wind turbine (FOWT) to change its position based on the wind direction and its mooring system design presents an opportunity to further decrease wake losses in floating wind farms. In this work, we integrate the design of the FOWT mooring systems with the floating wind farm layout design with the goal of increasing the farm’s annual energy production. We use the Horns Rev 1 wind farm as a case study to demonstrate our method. The results show that allowing the FOWT to relocate can decrease wake losses up to 18%. Moreover, the newly developed mooring systems are less stiff and therefore allow larger motion of the FOWT; hence, the material cost of the mooring system decreases by an estimated 17%.

Investigating the impact of solar PV and wind energy systems on the strength of a longitudinal power grid

The integration of inverter-based generation (IBG), such as solar photovoltaic (PV) and wind systems, presents unique challenges for power grid strength, especially in regions with limited conventional generation capacity. This study investigates the impact of such integration on the strength of Nigeria's power grid, focusing on sparsely connected northern region with abundant renewable resources. Using the network response short-circuit ratio (NRSCR) metric, which accounts for interactions between IBGs, we assess grid strength in three case studies. Simulations were conducted with the Power System Simulation for Engineering (PSS®E) software. Static analysis reveals inherent weakness in the northern region, characterized by low short-circuit capacity. Integrating IBGs at nine strategic locations shows varying responses: strong buses (NRSCR > 10) adapt well, while weak buses (NRSCR < 10), particularly in Kano and Katsina, constrain the operational capacity of the IBGs. Furthermore, close interaction among IBGs at these locations significantly impacts the system's dynamic response, although planned addition of conventional generators offers marginal improvement. This work highlights the potential of renewable resources to address energy shortages but also underscores the crucial need for detailed design studies at each point of interconnection (PoI), considering the longitudinal grid layout in the northern region and potential limitations imposed by IBG interactions. The findings also offer a structured approach that can be applied to power grids with comparable IBG integration levels, similar to the energy landscape of Nigeria.

Research on Irregular Warehouse Layout Based on Optimised Genetic Algorithm

Logistics is playing a significant role in supporting economic growth and material security during the epidemic period and it has been experiencing a rapid development in recent years. With the issues of personalisation and cost, the economy and society ask for higher requirements for logistics storage systems. The rational design of the functional area layout is an essential step to improve the operational efficiency of the logistics warehousing system. In reality, due to warehouse design and equipment application, there has been a gradual increase in irregular warehouses. By taking an irregular warehouse as an example, combining the operation status quo, this paper clarifies the functional area settings and constructs a 0–1 integer planning model based on the grid and systematic layout planning method with constraints, such as the unique functional attributes of the grid. We optimised the genetic algorithm based on the warehouse irregularity factor and the grids factor, and then solve it through MATLAB. Finally, by using the Flexsim software, simulation metrics were selected for evaluation, the method feasibility is verified.

Towards a cutting‐edge metallization process for silicon heterojunction solar cells with very low silver laydown

AbstractWithin this work, we investigate the potential to optimize the screen‐printed front side metallization of silicon heterojunction (SHJ) solar cells. Three iterative experiments are conducted to evaluate the impact of the utilized fine mesh screen configurations and grid layout adaption (finger pitch) for the front side metallization on silver laydown and electrical performance of the solar cells. With respect to the screen configuration, we compare the performance of a fine‐mesh knotless screen to a conventionally angled screen demonstrating an additional gain of Δη = +0.1%abs due to reduced shading losses. Additionally, a grid layout is improved by increasing the number of contact fingers from 120 to 156. Furthermore, the current possibility to push the fine‐line printing process for low‐temperature pastes to the limit is investigated by reducing the nominal finger width wn to 20, 18, and 15 μm. It is shown that even the smallest nominal width of wn = 15 μm can be printed with high quality, leading to an additional efficiency gain of Δη = +0.15%abs as well as a reduction of silver paste laydown by −5 mg. Finally, a batch of champion cells is fabricated by applying the findings of the previous experiments, which results in a maximum efficiency of ηmax = 23.2%. Compared to the reference group without optimization, this corresponds to a gain of Δη = +0.17%abs, which comes along with an additional decrease of the silver paste laydown by approximately −2 mg. This emphasizes the significance of consistent optimization of the screen‐printing process in terms of cell performance and resource utilization for SHJ solar cells.

Flexible closed-loop control device and control method for distribution network based on hybrid phase shifting transformer

With the increasingly complex structure of the distribution network and the increasing demand for power supply quality from the user side, relying solely on the original grid layout for power supply can no longer meet existing needs. Closed loop power supply can achieve uninterrupted load to improve power supply reliability. This article proposes a flexible loop closing device based on HPST for the case of large voltage phasor differences on both sides of the busbar loop closing point in the distribution network and proposes corresponding flexible loop closing and load transfer strategies based on the characteristics of HPST. Finally, a simulation of loop closure and power control was conducted based on the 10 kV distribution network loop closure scenario, verifying the feasibility of the HPST flexible loop closure device and the effectiveness of the control strategy.

Decision-making for sustainable urban transportation: A statistical exploration of innovative mobility solutions and reduced emissions

This research aims to investigate sustainable urban transportation decision-making through innovative mobility solutions, aiming to curtail emissions. To this end, this research presents a smart stochastic architecture to optimize renewable energy-dependent systems, addressing challenges in networked microgrids. By integrating electric vehicle (EV) charging demands and harnessing the unpredictability of renewable energy resources into the urban networks, the research introduces a vehicle-to-grid layout and a novel machine learning-enabled probabilistic Technique. These advancements cover the way for stable, sustainable, and efficient urban transportation systems with reduced environmental impact. A smart stochastic architecture to optimize the operation and management of such systems that rely heavily on renewable energy is proposed in this study, taking into account the poor reliability and complicated energy management in networked microgrids (MGs). The stochastic and variable charging EVs and also the unpredictability of renewable energy resources (RERs) are incorporated in the suggested layout. A vehicle to grid layout, which has become suitable for the MG cost function, is being used for mitigating adverse impacts of vehicles on MGs. In order to support the use of RERs, this study proposes a new machine learning-enabled probabilistic method utilizing support vector machine and point estimation methods for keeping the system in a stable state taking into account their random behavior. Furthermore, this paper develops a novel optimization algorithm using modified particle swarm optimization to determine what is optimal. IEEE systems evaluate the suitability of the suggested smart layout.

Using a Space Syntax Approach to Enhance Pedestrians’ Accessibility and Safety in the Historic City of George Town, Penang

Contemporary urban development places a critical emphasis on pedestrian environments, especially in historic cities like George Town, which is a UNESCO World Heritage Site in Malaysia. Although survey questionnaires effectively captured public perceptions of issues such as poor road connectivity, weak accessibility, crime and safety concerns in George Town, they fell short in providing a comprehensive understanding of the root causes. This study leverages space syntax theory to model and analyze George Town’s unique pedestrian landscape, aiming to identify strategies for improving pedestrian networks in historical urban landscapes. Space syntax theory, known for revealing structural issues within urban contexts, is applied after a thorough examination of George Town’s urban layout, climate, architectural features, and development policies. George Town employs an informal grid layout widely utilized in British colonial port cities to enhance overall efficiency. The predominant architectural form is the shophouse, which is characterized by a ground level designed for pedestrian movement known as the “five-foot way” and adapted to Malaysia’s climate. Various axis drawing methods for the unique five-foot way under different circumstances are considered. The George Town special area plan (SAP) emphasizing heritage preservation guides development policies, thus requiring an inclusive approach to pedestrian environments. This enhances the practical significance of the current study, with the eastern and northern coastal areas serving as crucial focal points for investigation. This approach results in a comprehensive spatial model that captures the essence of George Town’s pedestrian landscape. Evaluation using space syntax indicators such as connectivity, integration, intelligibility, and choice reveals issues like poor overall network connectivity, inadequate access to key attractions, suboptimal integration, concentrated pedestrian flows, and significant safety concerns, which are exacerbated by limited infrastructure on certain two-way roads and a lack of zebra crossings. The practical implications of this study include recommendations for enhancing pedestrian spaces along identified roads and strategically installing zebra-crossings. This research is significant for its focus on a historical city in a Southeast Asian developing country, deeply integrating local environmental characteristics and providing insights into urban planning and optimization, thereby serving as a reference for similar cities.

Choroidal thickness in relation to diopter and axial length among myopic children.

The aim of this study was to analyze the relationship between diopter (D) and choroidal thickness in myopic children by describing the values of choroidal thickness, and explore choroidal thickness as an important indicator for evaluating the progression of myopia. The study included myopic and emmetropic children aged 6-14 years (156 eyes) from the Second Hospital of Dalian Medical University. The participants were divided into four groups according to the spherical equivalent refraction (SER): low myopes, moderate myopes, high myopes, and emmetropes. Choroidal thickness was measured in nine areas using the Early Treatment Diabetic Retinopathy Study (ETDRS) grid layout, which divided the areas into concentric circles of 0 × 0 mm, 3 × 3 mm, and 5 × 5 mm from the Sub Fovea. The images were obtained manually with spectral-domain optical coherence tomography scanner. There were significant differences of choroidal thickness in the nine areas of the ETDRS grid for all myopes. The distribution of choroidal thickness in low and moderate myopes were different from that in high myopes. In the horizontal direction, choroidal thickness decreased from the temporal to nasal areas for all myopes. In the vertical direction, the choroidal thickness in the perifovea was smaller than that in the parafovea (SER ≥ -2.75D), and the choroidal thickness in the perifovea was greater than that in the parafovea (SER < -2.75D). When comparing emmetropes with myopes, the closer the choroidal thickness was to the central fovea, the more significant the differences were, while the differences were smaller to the perifovea. Among all children, choroidal thickness was positive to SER and negative to axial length (AL) in all areas. For every 1D increase in myopia, the subfoveal choroidal thickness decreased by 13 μm, and for every 1 mm increase in AL, the subfoveal choroidal thickness decreased by 23 μm. Furthermore, SER and AL showed the strongest correlation with choroidal thickness in the inferior area. Optical coherence tomography results revealed choroidal thickness was thinner in myopic children. Choroidal thickness was positive to SER and negative to AL. Therefore, we consider choroidal thickness to be an important indicator for evaluating the myopia progress.

Effects of spatial resolution of the data on dynamic mode decomposition and its quantitative analysis

Dynamic mode decomposition (DMD), based on Koopman analysis, is a tool capable of spatiotemporal analysis for various spatial resolutions, from one-dimensional signals to three-dimensional computational fluid dynamics (CFD) and experimental data. Outputs of the DMD consist of amplitudes, frequencies, decaying rates, and spatial modes. However, the effects of spatial resolution (time-series data in one-dimensional signal and spatial grid in two-dimensional data) and quantitative analysis of DMD are limited to one-dimensional signal data. In this study, the effects of spatial resolution with a fixed time scale of data and correction using scaling factors 2/A on DMD amplitudes and A on DMD spatial mode strengths are investigated, where A is the number of the time-series data in one-dimensional signal or the number of the spatial grid in two-dimensional data. First, proofs of the scaling factors for one-dimensional(line layout) and two-dimensional(grid layout) data are presented. Second, the effect of spatial resolution on the amplitudes and spatial mode strengths and their scaled results are confirmed using one-dimensional artificial signal data, two-dimensional artificial signal field data, two-dimensional vortex shedding simulation data, and two-dimensional pulsating flow experimental data with various data resolutions. The results show that the amplitude increases proportionally with the spatial resolution, and the spatial mode strength is inversely proportional to the time series or spatial resolution of the data in all cases. As a result of applying the scaling factors to one-dimensional artificial signal and two-dimensional artificial signal field data, the amplitudes and spatial modes contain the same values regardless of the change in spatial resolutions. The scaled amplitudes and spatial mode strengths on vortex shedding simulation and two-dimensional laminar pulsating jet show good agreements with slight differences, regardless of the spatial resolution change. The proposed scaling factor can be applied to compare data quantitatively obtained with different spatial resolutions.

Multi-Agent Reinforcement Learning Resources Allocation Method Using Dueling Double Deep Q-Network in Vehicular Networks

The communication between vehicle-to-vehicle (V2V) with high frequency, group sending, group receiving and periodic lead to serious collision of wireless resources and limited system capacity, and the rapid channel changes in high mobility vehicular environments preclude the possibility of collecting accurate instantaneous channel state information at the base station for centralized resource management. In addition, road and traffic safety have very strict requirements for low-latency, high-reliability communication, and information transmission is only valuable within a certain range, and requires timeliness. For the Internet of Vehicles (IoV), it is a fundamental challenge to achieve low latency and high reliability communication for real-time data interaction over short distances in a complex wireless propagation environment, as well as to attenuate and avoid inter-vehicle interference through a reasonable spectrum allocation. To solve the above problems, this paper proposes a resource allocation (RA) method using dueling double deep-Q network reinforcement learning (RL) with low-latitude fingerprints and soft-update architecture (D3QN-LS) while constructing a multi-agent model based on a Manhattan grid layout urban virtual environment, with communication links between V2V links acting as agents to reuse vehicle-to-infrastructure (V2I) spectrum resources. These agents work in concert, interact with the environment, receive appropriate observations, rewards, and ultimately learn to improve power and spectrum allocation to provide a better entertainment experience and safer driving environment for users. We also address the shortcomings in existing literature studies. Firstly, the low upper limit of transmitted data volume; Secondly, the artificial assumption that the spectrum is consistent with the number of V2V links, which is insufficient for future applications in spectrum shortage sections. We accordingly extend the amount of transmitted data while adding a scenario where the spectrum resources are relatively short, i.e., the number of V2V links is significantly larger than the amount of spectrum. Experimental results show that with proper training mechanism and reward function construction, multiple intelligence can cooperate effectively. Therefore, the total link capacity of the V2I link and the success rate of periodic security information transmission are further improved.

Virtual grid layout with direction constraints for autonomous mobile robot routing performance improvement

Virtual grid layout with direction constraints for autonomous mobile robot routing performance improvement

Vehicle routing for connected service areas - a versatile approach covering single, hierarchical, and bi-criteria objectives

Vehicle routing in urban areas or in-house tour planning is characterized by the fact that tours have to service orders in areas with limited road or aisle access. During last mile delivery, courier service providers often face the situation that subsets of customers in urban areas are located along a single street that can be accessed from only one or two directions. This also applies to warehouses, where, due to the given grid layout, pickers locate products on shelves only in specific areas positioned along an aisle between two neighboring cross aisles. By being confronted with a substantial time and/or cost pressure, those tour planning applications have to deal with the trade-off between service orientation and cost minimization. In order to cover many of those applications, this study proposes a general model that integrates the definition of customizable service areas with limited access and soft due dates of urgent orders, whereas the objective function can be defined in a versatile way covering to choose between a single objective, a hierarchical, and a bi-criteria objective system. The model is dubbed the Vehicle Routing Problem of Service Areas (VRPSA). A comprehensive complexity analysis of the VRPSA for different objective systems shows that a pure travel cost minimization variant can be solved to optimality in polynomial time, whereas the bi-criteria variant simultaneously pursuing travel cost and tardiness cost minimization is proven to be intractable. In order to generate tour plans, a customizable best-first branch-and-bound algorithm is developed and assessed through a computational study.

Investigating the Impact of Different Partial Overlap Levels on the Perception of Visual Variables for Categorical Data

The overlap of visual items in data visualization techniques is a known problem aggravated by data volume and available visual space issues. Several methods have been applied to mitigate occlusion in data visualizations, such as random jitter, transparency, layout reconfiguration, focus+context techniques, etc. This paper aims to present a comparative study of the reading of visual variables values with partial overlap. The study focuses on categorical data representations varying the percentage limits of partial overlap and the number of distinct values for each visual variable: hue, lightness, saturation, shape, text, orientation, and texture. A computational application generated random scenarios for a unique visual pattern target to perform location tasks. Each scenario involved presentation of the visual items in a grid layout with 160 elements (10 × 16), each visual variable had from three to five distinct values encoded, and the partial overlap percentages applied, represented by a gray square in the center of each grid element, were 0% (control), 50%, 60%, and 70%. Similar to the preliminary tests, the tests conducted in this study involved 48 participants organized into four groups, with 126 tasks per participant, and the application captured the response and time for each task performed. The results analysis indicated that the hue, lightness, and shape visual variables were robust to high percentages of occlusion and gradual increase in encoded visual values. The text visual variable showed promising results for accuracy, and the resolution time was a little higher than for the last visual variables mentioned. In contrast, the texture visual variable presented lower accuracy to high levels of occlusion and more different visual encoding values. Finally, the orientation and saturation visual variables exhibited the highest error and worst perfomance rates during the tests.

Das Quelle-Fertighaus

Abstract The steel prefabricated family house ›Quelle-Fertighaus‹ designed and constructed by the German company Quelle, is an innovative modular system commercialised in 1962. All aspects of the Quelle-Fertighaus are planned on the principle of minimal effort for maximal flexibility. The clever design of the ground plan based on a 4 m × 7 m module offers the flexibility for either one to three additional modules. The steel construction is innovative and unique, consisting of load-bearing portal frames acting as braces. The house design is furthermore characterised by a simple metrical grid layout and the practical placement of the foundation and basement, which allowed the very cost-effective production and the lowest price for a prefabricated family house in Germany during the postwar era. Nowadays its portal-frame-construction offers an interesting approach for its renovation and transformation according to present building demands.

Offshore Electrical Grid Layout Optimization for Floating Wind—A Review

Electrical grid layout optimization should consider the placements of turbines and substations and include effects such as wake losses, power losses in cables, availability of different cable types, reliability-based power losses and operational/decommissioning cost besides the initial investment cost. Hence, optimizing the levelized cost of energy is beneficial capturing long-term effects. The main contribution of this review paper is to identify the current works and trends on electrical layout optimization for offshore wind farms as well as to analyze the applicability of the found optimization approaches to commercial-scale floating wind farms which have hardly been investigated so far. Considering multiple subproblems (i.e., micrositing and cabling), simultaneous or nested approaches are advantageous as they avoid sequential optimization of the individual problems. To cope with this combinatorial problem, metaheuristics seems to offer optimal or at least close-to-optimal results while being computationally much less expensive than deterministic methods. It is found that floating wind brings new challenges which have not (or only insufficiently) been considered in present optimization works. This will also be reflected in a higher complexity and thus influence the suitability of applicable optimization techniques. New aspects include the mobility of structures, the configurations and interactions of dynamic cables and station-keeping systems, the increased likelihood of prevailing heterogeneous seabeds introducing priority zones regarding anchor and riser installation, the increased importance of reliability and maintainability due to stricter weather limits, and new floating specific wind farm control methods to reduce power losses. All these facets are crucial to consider when thoroughly optimizing the levelized cost of energy of commercial-scale floating offshore wind farms.

Aerodynamic Characteristics Analysis of Rectifier Drum of High-Speed Train Environmental Monitoring Devices

To study the aerodynamic characteristics of the convex structure of a surface-monitoring device on a high-speed train and to evaluate its impact on the aerodynamic performance of the high-speed train, numerical simulation research was conducted on three different layouts of the monitoring device. The computational fluid dynamics (CFD) method was used for the simulation study, and the unsteady compressible NS equation was used as the control equation. Hexagonal grid technology was used to reduce the demand for the grid quantity. The rationality of the grid size and layout was verified through grid independence research. To increase the accuracy of the numerical simulation, the γ-Reθ transition model and improved delayed detached eddy simulation (IDDES) method were coupled for the simulation research. The aerodynamic characteristics of the different operation directions and configurations were compared and analyzed. The research results showed that the windward side of the single pantograph detection device experienced positive pressure, and the sideline and leeward sides experienced negative pressure. Increasing the fillet radius of the sideline could appropriately reduce the aerodynamic resistance. When the speed was about 110 m/s, the drag force coefficient of the detection device was 210~410 N, and the lateral force was small, which means that it had little impact on the overall aerodynamic force of the train. According to the results of the unsteady analysis of the layout with a large space, the resistance during forward travel was greater than that during negative travel. The streamlined upwind surface was conducive to reducing the scope of the leeward separation zone and the amplitude of the pressure fluctuation in the leeward zone, and it thus reduced the resistance. For the running trains, a vortex was formed on their leeward surface. The pressure monitoring results showed that the separated airflow had no dominant frequency or energy peak. The possibility of the following train top and other components experiencing resonance damage is low.