Spatial Resource Utilization Research Articles

Practical time‐varying formation cooperative control for high‐order nonlinear multi‐agent systems avoiding spatial resource conflict via safety constraints

AbstractThe operation of multi‐agent systems (MAS) in space necessitates considerations for obstacle avoidance, collision prevention, and connectivity among agents. This coupling conflict, stemming from spatial resource utilization, poses a significant and non‐negligible threat to the safe operation of MAS. This article proposes a consensus control scheme for the time‐varying formation of MAS, incorporating functions for maintaining connectivity, collision avoidance, and obstacle dodging. This scheme effectively constrains the time‐varying formation tracking error within an arbitrarily small range. The considered system model takes a high‐order nonlinear form, with uncertainties and disturbances present in each order. This grants the control scheme with high generality and practicability. By employing barrier Lyapunov function to delineate the safe operational space of MAS, conflicts in spatial resource utilization are avoided. This approach simultaneously fulfills the requirements for connectivity maintenance, collision avoidance, and obstacle dodging in the safe operation of MAS. An additional rotation operator is integrated into the controller to smoothly address the “minima” problem, eliminating the need for external intervention. Gaussian radial basis function is used to estimate the nonlinear terms, uncertainties, and unknown perturbation online in the system. The stability of the MAS under the proposed control scheme is analyzed through Lyapunov function. Finally, numerical simulation results are demonstrated to explain the effectiveness of the control scheme.

A State-Interactive MAC Layer TDMA Protocol Based on Smart Antennas

Mobile ad hoc networks are self-organizing networks that do not rely on fixed infrastructure. Smart antennas employ advanced beamforming technology, enabling ultra-long-range directional transmission in wireless networks, which leads to lower power consumption and better utilization of spatial resources. The media access control (MAC) protocol design using smart antennas can lead to efficient usage of channel resources. However, during ultra-long-distance transmissions, there may be significant transport delays. In addition, when using the time division multiple access (TDMA) schemes, it can be difficult to manage conflicts arising from adjacent time slot advancement caused by latency compensation in ultra-long-range propagation. Directional transmission and reception can also cause interference between links that reuse the same time slot. This paper proposes a new distributed dynamic TDMA protocol called State Interaction-based Slot Allocation Protocol (SISAP) to address these issues. This protocol is based on slot states and includes TDMA frame structure, slot allocation process, interference self-avoidance strategy, and slot allocation algorithms. According to the simulation results, the MAC layer design scheme suggested in this paper can achieve ultra-long-distance transmission without conflicts. Additionally, it can reduce the interference between links while space multiplexing. Furthermore, the system exhibits remarkable performance in various network aspects, such as throughput and link delay.

Ecological Niche Studies on Hylurgus ligniperda and Its Co-Host Stem-Boring Insects

Hylurgus ligniperda (Fabricius), a significant quarantine pest, has recently invaded China, marking a new spread outside its known global distribution. This study aims to clarify the invasion and colonization mechanisms of H. ligniperda in Shandong Province, a primary colonization site. This study employed sampling surveys and analysis of damaged wood, discovering that the wood-boring insects sharing the same host as H. ligniperda mainly include Cryphalus sp., Arhopalus rusticus, and Shirahoshizo sp. Through ecological niche theory, the study analyzed the ecological niche relationships between H. ligniperda and these three wood-boring insects, from the perspectives of temporal and spatial resource utilization. The results reveal that these insects could cause damage to P. thunbergii trees at different health levels, with H. ligniperda being the most destructive. The ecological niches of insect populations varied significantly by tree vigor and height. Cryphalus sp. occupied the entire trunk, whereas A. rusticus and Shirahoshizo sp. were concentrated in the lower-middle trunk and the root section up to a depth of 1 m. Notably, H. ligniperda primarily targeted tree roots. Due to the differences in spatial distribution, there was no intense competition between H. ligniperda and other wood-boring insects. With a decline in the health of the host tree, Cryphalus sp. ascended the trunk, whereas H. ligniperda spread deeper into the roots and A. rusticus moved towards the base of the trunk and the top of the roots. Shirahoshizo sp. showed a less defined distribution pattern. Therefore, H. ligniperda was more dominant during the later stage of damage. The position occupied by each insect on the trunk was relatively stable, and the ecological niche overlap value with H. ligniperda was low in terms of temporal resources. Therefore, H. ligniperda and other stem-boring pests exhibit coexisting populations mainly through the allocation and utilization of spatial resources, eventually promoting the successful colonization of H. ligniperda.

A Novel Parts-to-Picker System with Buffer Racks and Access Racks in Flexible Warehousing Systems

With the tremendous development of the logistics industry, the global market of automated warehousing has been growing rapidly. Meanwhile, the warehousing industry shows drawbacks, such as low storage capacity and poor efficiency. By comparing and analyzing the shuttle-based storage and retrieval system (SBS/RS), miniload automated storage and retrieval system (AS/RS), and KIVA system, a novel efficient parts-to-picker approach in flexible warehousing systems is proposed. Among them, buffer racks and access racks, associated with the access of automated mobile robots (AMRs) and stackers are used. The results show that compared with other parts-to-picker systems (such as the KIVA system), this system provides a significant increase in storage capacity (more than three times), and the picking efficiency is also very high at various layout scales, where the picking efficiency is no less than the KIVA system when the number of AMRs reaches the max. The novel system is suitable for small-, medium-, and large-scale warehouses in terms of showing high capacity and producing excellent space utilization. More importantly, this system can easily compete with its traditional counterparts by using a layout of high density without much increase in cost. This sustainable improvement realizes the efficient utilization of spatial resources and provides important support for the construction of green supply chains.

Spatio-Temporal Pattern and Conflict Identification of Production–Living–Ecological Space in the Yellow River Basin

Production–living–ecological space (PLES) is the main body of the optimization of the development and protection pattern of territorial space, and the spatial conflict in PLES reflects a struggle for ecological protection and socio-economic development in the process of spatial development and utilization. The Yellow River Basin is one of the most concentrated and prominent areas of spatial conflict of PLES in China. Therefore, clarifying the spatio-temporal pattern of PLES of the region and scientifically identifying the characteristics of its spatial conflict will significantly improve the efficiency of comprehensive utilization of spatial resources, promote the integrated and orderly development of resource elements in the basin, and eventually achieve the strategic goals of ecological protection and high-quality development of the Yellow River Basin. In this research, the CA–Markov model was applied to simulate the spatio-temporal pattern of PLES in the Yellow River Basin from 2010 to 2025, and the landscape ecology method was adopted to construct the spatial conflict of the PLES measurement model for identifying the spatio-temporal trends of conflicts and their intensity. The results reveal that, from 2010 to 2025, ecological–production space (EPS) dominates the PLES in the Yellow River Basin, as its total area remains stable amid fluctuations; living–production space (LPS) shows the most notable change, as it grows yearly along with urbanization and industrialization process of the region; the transition between ecological–production space (EPS) and production–ecological space (PES) is the most frequent, and the two also account for the largest area. Spatial conflict of PLES in the Yellow River Basin is mainly reflected in the encroachment of LPS on other PLES, concentrated in the regions from Hekou Town to the left bank of Longmen, Fen River, Shizuishan to the southern bank of Hekou Town, and Daxia River and Tao River in the Yellow River Basin. From 2010 to 2025, the space conflict composite index of PLES (SCCI) of most regions in the basin lies within 0.7, which is a stable or basically controllable level. Among the 29 tertiary water resource divisions in the Yellow River Basin, the SCCI of 15 indicate a major, decreasing trend.

Spatial-Reuse-Based Efficient Coexistence for Cellular and WiFi Systems in the Unlicensed Band

With the increasing data traffic in the fifth-generation (5G) communication system, the 5G new radio extended to unlicensed bands (5G NR-U) has become a promising approach to relieve the heavy pressure on the cellular system. To achieve the efficient coexistence with the WiFi system and improve the efficiency of temporal, spectral and spatial resource utilization, we first divide the transmission space into two subspaces by leveraging spatial reuse, where the data transmitted by cellular user equipments (UEs) falls into one subspace and the data transmitted by Internet of Things (IoT) devices coexisting with WiFi users through power control is in the other subspace. Then, the coexistence among cellular UEs, IoT devices, and WiFi users is formulated as an optimization model with the aim of maximizing the cellular system throughput via the joint power and subchannel allocation under the interference constraint. Although the resulting optimization problem is a mixed-integer nonlinear programmming, we decompose it into two subproblems and develop an alternating iterative approach to effectively solve them. Also, the closed-form allocations of the power and subchannels are obtained. Simulation results confirm that the proposed scheme can improve the cellular system performance and guarantee the coexistence in the unlicensed band.

The Features and Causes of Spatial Planning Conflicts in China: Taking Urban Planning and Land-Use Planning as Examples

The conflicts in spatial planning are the main reason that restricts the sustainable development of land use in China, and it is also the main barrier to the building of “Territorial Spatial Planning System”. This study analyzes the conflicts between urban planning and land-use planning from the three dimensions of construction land, basic farmland and ecological land based on a land-use transition matrix with the central urban area of Liupanshui City, Guizhou Province as a case region, and analyzes the causes of spatial planning conflicts from the perspectives of the central and local governments in terms of their preferences and interactive relationships. The main conclusions of this paper are as follows. (1) Urban planning and land-use planning have comprehensive conflicts with each other in terms of the construction land, basic farmland and ecological land, i.e. the scale of construction land in urban planning is 154% of that in land-use planning, and the scale of basic farmland in urban planning is 88.56% of that in land-use planning. (2) Central and local governments are the two main stakeholders of spatial planning, and they have different preferences for the utilization of spatial resources at prefecture-level cities. The central government is concerned about food security, and therefore, pays more attention to the protection of cultivated land, while the local governments focus on economic benefits and the ecological environment, and therefore, pay more attention to construction and ecological lands. (3) The urban planning system is a bottom-up design system, which determines that urban planning mainly reflects the preferences of local governments, while the land-use planning system is a top-down design system, which determines that land-use planning mainly reflects the central government’s preferences. The policy implication of this study is that in order to manage spatial planning conflicts, it is necessary to manage the conflicts of interest among stakeholders.

Spatial function regionalization and governance of coastal zone: A case study in Ningbo City

Reasonable development and utilization of spatial resources in the coastal zone not only affects the development quality of the marine economy but also impacts the utilization efficiency of spatial resources, playing an important role in regional sustainable development. Depending on the natural, economic, and societal characteristics of a region, research topics such as using relevant methods to divide the coastline, proper spatial development of the coast, protecting coastal zones, and achieving higher spatial resource distribution efficiency have recently become hot topics in geographic research. Most of the scholars construct the evaluation index system from the perspective of economic and ecological factors and undertake some exploration of the division methods. However, the selection of indicators for a coastal zone needs a different and more scientific approach. There is a need for emphasizing the overall strategy of land-ocean integration in developing spatial resources in a coastal zone. Taking the coastal zone in Ningbo as an example, this paper develops a new evaluation framework and spatial function regionalization method that is used to divide the coastline and coastal zone. Based on the perspective of overall strategy for the land and ocean, we evaluate the suitability of coastline development. We then propose the spatial function regionalization of the coastal zone. Finally, based on the status quo of spatial development in Ningbo, we divide the coastal zone into ecological space, production space and living space, and propose adjustment directions and control requirements for the different types of spatial layouts.

Geomorphologic mapping by remote sensing in radial submarine sand ridges

Radial submarine sand ridges are large- sized sandy accumulation bodies in offshore area of northern Jiangsu. Because of their complicated hydrodynamic environment and geomorphology,it is very difficult to obtain the field investigation data. This paper is based on the color and texture reflected on the remote sensing image, Geomorphologic mapping was conducted in combination with the measured terrain data and historical charts as well as the historical geomorphological map. In addition,the spatial characteristics were analyzed. The results show that the use of remote sensing images to draw the geomorphologic map of radial submarine sand ridges can provide practical and reliable scientific basis not only for the study of the geomorphologic structure but also for the development and utilization of spatial resources.

A Study on Space Composition of Pottery and Utilization of Spatial Resources in Shigaraki

A Study on Space Composition of Pottery and Utilization of Spatial Resources in Shigaraki

A Simulation Model for Spatial Scheduling of Dynamic Block Assembly in Shipbuilding

Accurately predicting the required spatial resource for aggregate block assembly in shipyard production is difficult due to the following reasons: 1) lack of optimal block on-jig configuration and 2) the dynamic and stochastic nature of production system. Consequently, managerial objectives are seldom achieved without effective production planning and control. In this study, a look-ahead scheduling mechanism with an application of discrete-event simulation is proposed to solve the dynamic spatial scheduling problem. A systematic simulation-based framework is suggested for validating schedules generated at high-level planning together with a heuristic-based optimizer for improving spatial resource utilization. Through imitation of the dynamic spatial operation under various priority rules, statistical analysis of resultant performance can be conducted to select the best performing control policy. A case study with computational experiments is performed and results are reported. Issues relevant to system implementation are highlighted as well.

A Comparative Study on Uplink Sum Capacity with Co-Located and Distributed Antennas

It has been long believed that the distributed antenna system (DAS) has great potentials for capacity improvement compared to the traditional cellular system with co-located base-station antennas. Intuitively, the distributed characteristic of antennas provides a much more efficient utilization of spatial resources. It, however, also significantly complicates the channel modeling and system analysis. Despite an increasing amount of academic attention and industrial interest, how to characterize the capacity advantages of the DAS in the multiuser scenario remains largely unknown. In this paper, we present a comparative study on the uplink ergodic sum capacity with multiple base-station antennas either co-located or uniformly distributed within a given area. We demonstrate that under the same consumption of transmission power, enormous gains can be achieved by the distributed antenna layout thanks to (1) reduced minimum access distance of each user; and (2) enhanced channel fluctuations which provide a significant boost to the sum capacity when the channel state information is available at both the transmitter and the receiver sides. We further apply the analysis to a cellular system with full cooperation among base stations. The comparison verifies that the DAS yields a much higher sum capacity, and capacity gains increase with the number of base-station antennas per cell.

Regional processes in mangrove ecosystems: spatial scaling relationships, biomass, and turnover rates following catastrophic disturbance

Physiological processes and local-scale structural dynamics of mangroves are relatively well studied. Regional-scale processes, however, are not as well understood. Here we provide long-term data on trends in structure and forest turnover at a large scale, following hurricane damage in mangrove ecosystems of South Florida, U.S.A. Twelve mangrove vegetation plots were monitored at periodic intervals, between October 1992 and March 2005. Mangrove forests of this region are defined by a −1.5 scaling relationship between mean stem diameter and stem density, mirroring self-thinning theory for mono-specific stands. This relationship is reflected in tree size frequency scaling exponents which, through time, have exhibited trends toward a community average that is indicative of full spatial resource utilization. These trends, together with an asymptotic standing biomass accumulation, indicate that coastal mangrove ecosystems do adhere to size-structured organizing principles as described for upland tree communities. Regenerative dynamics are different between areas inside and outside of the primary wind-path of Hurricane Andrew which occurred in 1992. Forest dynamic turnover rates, however, are steady through time. This suggests that ecological, more-so than structural factors, control forest productivity. In agreement, the relative mean rate of biomass growth exhibits an inverse relationship with the seasonal range of porewater salinities. The ecosystem average in forest scaling relationships may provide a useful investigative tool of mangrove community biomass relationships, as well as offer a robust indicator of general ecosystem health for use in mangrove forest ecosystem management and restoration.

Spatial Ecological Hierarchies: Coexistence on Heterogeneous Landscapes via Scale Niche Diversification

Spatially heterogeneous environments are generally characterized by nested landscape patterns with resource aggregations on several scales. Empirical studies indicate that such nested landscape patterns impose selection constraints on the perceptive scales of animals, but the underlying selection mechanisms are unclear. We investigated the selection dynamics of perceptive scale within a spatial resource utilization model, where the environment is characterized by its resource distribution and species differ in their perceptive scales and resource preemption capabilities. Using three model landscapes with various resource distributions, we found that the optimal perceptive scale is determined by scale-specific attributes of the landscape pattern and that the number of coexisting species increases with the number of characteristic scales. Based on the results of this model, we argue that resource aggregations on different scales act as distinct resources and that animal species of particular perceptive scales are superior in utilizing resource aggregations of comparable spatial extent. Due to the allometric relationship between body size and perceptive scale, such fitness difference might result in discontinuous body mass distributions.

Spatio-temporal variability of benthic macroinvertebrate community attributes and their relationship to environmental factors in a large river (Danube, Austria)

The macroinvertebrate community of the riverbed sediments was examined for biodiversity and spatial resource utilization at four sites on a cross-section of the River Danube in Austria between September 1995 and August 1996. The sites differed in water velocity, sediment composition and habitat stability. A species-accumulation curve based on all samples suggested an open community, with 164 species present at the four sites. Of these, 81 species were Chironomidae, 33 species were Oligochaeta and these two groups accounted for some 95 % of the total numbers of macroinvertebrates. Altogether, 93 species occurred at site 1, 82 at site 2, and 71 at site 3. Site 4 had 142 species, of which 47 did not occur at any of the other sites; some (mainly chironomids) possibly immigrate from a neighbouring backwater. Redundancy Analysis (RDA) was used to describe the variation in the relationship between these community attributes, together with total abundances, and environmental factors. The first two RDA-axes separated the four sites with respect to habitat stability and sediment composition; the temporal scale was given by the third and fourth RDA-axes, related to water temperature and flow, respectively. The centroids of the site scores exhibited a clear circular pattern for successive sampling dates, indicating relatively predictable environmental conditions over the year. In general, habitat stability was the major factor associated with community attributes. Lower sediment turnover near the riverbanks coincided with increased densities and decreased species turnover. Highest values for species richness and total abundance occurred at a riverbank site of intermediate stability and greatest sediment heterogeneity, suggesting that the communities were structured by a combination of several factors. Parameters describing resource utilization patterns were only weakly associated with changes in environmental conditions, suggesting that food distribution and/or biotic interactions also influenced community structure.

Community structure and resource use of oligochaetes (Annelida)in relation to hydrophysical factors in a large river

The oligochaete community of streambed sediments was examined with respect to biodiversity and spatial resource utilization at four sites on a cross-section of the River Danube in Austria between September 1995 and August 1996. The sites differed in hydraulics, sediment composition and habitat stability. At all sites, species-accumulation curves showing the increase in number of species with increasing sampling effort agreed with a logarithmic model, suggesting that most of the present species have been found. Properties of the community were estimated using Jackknife techniques: species richness (range of mean values at the four sites: 30 to 36), H' diversity (0.9 to 1.1), evenness (0.15 to 0.32), spatial resource width (0.01 to 0.05), spatial resource overlap (0.08 to 0.25), spatial species aggregation (0.66 to 0.72), temporal community persistence (Kendal's correlation coefficient: 0.52 to 0.66) and β-diversity (3.6 to 6.1). RDA (Redundancy Analysis) was used to correlate the community properties and species abundance with environmental factors. Habitat stability and sediment heterogeneity were the major factors associated with community structure. Decreasing stability coincided with decreasing densities, species richness and increasing species turnover, whereas sediment composition seemed to fine-tune community structure, coinciding with evenness and spatial resource utilization patterns. Species-abundance patterns agreed well with the log-normal model. Moderate community persistence and stability of the streambed sediments therefore suggest that the log-normal model may be a good descriptor for communities of intermediately disturbed habitats like large rivers rather than stable habitats.

Spatial resource utilization and species assemblages of larval and juvenile fishes

Spatial resource utilization and species assemblages of larval and juvenile fishes