Coexistence Problem Research Articles

Linking resource- and disturbance-based models to explain tree-grass coexistence in savannas.

Savannas cover a significant fraction of the Earth's land surface. In these ecosystems, C3 trees and C4 grasses coexist persistently, but the mechanisms explaining coexistence remain subject to debate. Different quantitative models have been proposed to explain coexistence, but these models make widely contrasting assumptions about which mechanisms are responsible for savanna persistence. Here, we show that no single existing model fully captures all key elements required to explain tree-grass coexistence across savanna rainfall gradients, but many models make important contributions. We show that recent empirical work allows us to combine many existing elements with new ideas to arrive at a synthesis that combines elements of two dominant frameworks: Walter's two-layer model and demographic bottlenecks. We propose that functional rooting separation is necessary for coexistence and is the crux of the coexistence problem. It is both well-supported empirically and necessary for tree persistence, given the comprehensive grass superiority for soil moisture acquisition. We argue that eventual tree dominance through shading is precluded by ecohydrological constraints in dry savannas and by fire and herbivores in wet savannas. Strong asymmetric grass-tree competition for soil moisture limits tree growth, exposing trees to persistent demographic bottlenecks.

Philosophy, self-determination, peace and intercultural co-existence in Nigeria: an Igwebuike perspective

This paper has studied the issue of agitations for self-determination in Nigeria from an African philosophical point of view. It studied these agitations in the light of the amalgamation treaty of 1914, the Constitution of the Federal Republic of Nigeria and most importantly, extant international laws. The beauty of this piece is that it focused on major issues which constitute the basis for the agitations for self-determination in Nigeria namely religious marginalization, ethnic marginalization, economic marginalization and political marginalization. The burden of this piece is the issue of the problem of co-existence in Nigeria. This paper articulated its position based on Igwebuike philosophy as a theoretical framework, which emphasizes dialogue, justice and inclusive leadership as indispensable pathways to integration and national unity. For the purpose of this study, the historical and analytical methods of inquiry were patronized given that historical events were studied and the outcome of such events analysed. It submits that, rather than using force to quell the agitation for self-determination, the path of justice, dialogue and inclusive leadership should be explored as most cases of cessation are responses to the absence of these state ideals.

The Truth and Non-Truth of the “Social”. The Problem of Human Identity and Coexistence

The article discusses the concept of the “social”, which is basic for all social sciences and the object of study and perfecting impact. In professional literature, it has been revealed that the concept of the social is determined through predication with other significant phenomena of social life, such as relationships, actions, actors, structures, etc. Authors, in regard to their conception of “wisdom-oriented social science” and concretely of “sociology of wisdom”, suggest their own definition of the “social” as the intention, the image and the fulfilment of the improvement of human existence, coexistence and interaction of human beings as such. The new definition reveals the profound council of wisdom expressing the essential and principally preferable properties of nature, being and inner-perfection of the “social”.

Toward the Coexistence of Cognitive Networks for Vehicular Communications on TVWS for IEEE Std. 802.22

The IEEE 802.22 is a standard for wireless regional area networks to opportunistically operate in TV bands; however, sharing TV White Space (TVWS) spectrum creates a problem of coexistence because no mechanism is defined for coordinating channel usage among secondary networks. We propose a White Space Resource Sharing mechanism (WSRS) for fixed secondary and mobile IEEE 802.22 networks to improve network coexistence and spectrum efficiency. Based on power control and channel allocation, our mechanism allows the TVWS system to serve vehicular networks in scenarios where there are active secondary fixed networks and no more TVWS channels available for opportunistic usage. Unlike state-of-the-art mechanisms for coexistence in TVWS spectrum, our mechanism allocates resources to vehicles even when the density of fixed nodes and the transmission power of the fixed network cause high interference to the vehicular network. Our results show the offered channel capacity increases up to 50% using the proposed WSRS mechanism compared to the recent IEEE 802.22 standard that does not have a defined TVWS channel sharing mechanism. Furthermore, our WSRS mechanism implements a strategy to protect the fixed secondary network from interference caused by vehicular transmissions while promoting fair usage for both secondary networks.

Study on macro prediction method of oil production in oil field with multiple development modes

With the large-scale popularization and application of new EOR technology, it is inevitable to face the problem of coexistence of multiple development methods, and the mechanism of new EOR technology is complex, there are many influencing factors, there is no mature prediction method, and the prediction of oil production is complex and heavy. How to use the simple, fast and small error method to calculate the oil production under the coexistence of multiple development modes has become an urgent problem. In this paper, the prediction method of oil production in different structure is established. By using the development indexes such as the macro oil production rate, the basic change trend of the development indexes under different development modes is studied and judged, so as to predict the annual oil production of the oilfield. Taking the EOR method of chemical flooding as an example, using the field practice of the block in which chemical flooding has been implemented for many years, the change trend of the macro oil recovery rate is predicted, and the oil production of the tertiary oil recovery of the oil field is determined according to the reserves of different scale. At the same time, the prediction results of the oil production of the whole oil field are obtained by combining the prediction results of the water drive oil production. It is verified by examples that the prediction accuracy can meet the needs of oilfield production, realize the rapid and accurate prediction of oil production in the field with multiple development modes, and solve the problem that there is no mature prediction method for new technology.

RIS-Assisted Network Slicing Resource Optimization Algorithm for Coexistence of eMBB and URLLC

Enhanced mobile broadband (eMBB) and Ultra-Reliable and Low-Latency Communications (URLLC) are the two main services in the fifth-generation mobile network. URLLC services have stringent latency and reliability requirements, while eMBB services are designed to provide extremely high data rates for content delivery. The differentiated Quality of Service (QoS) requirements of the two services make their coexistence on the same bandwidth resources a challenging issue. To meet this challenge, we introduce reconfigurable intelligent surface (RIS) technology to assist in solving the resource allocation problem. The problem is formulated as two optimization problems. For the eMBB allocation problem, we jointly optimize the resource block allocation, power allocation, and RIS phase shift matrix and propose a two-stage alternating iterative algorithm to maximize the total traversal capacity of eMBB users. For the URLLC allocation problem, we maximize the URLLC packet reception rate and minimize the amount of eMBB rate loss while ensuring the quality of service for eMBB and URLLC. A heuristic URLLC allocation algorithm based on pre-configured RIS is proposed. Simulation results show that the proposed algorithm can meet the strict delay requirements of URLLC even when the URLLC packet reception rate is nearly 95.5%. Meanwhile, the total loss rate of eMBB service caused by the reuse of URLLC service is less than 6%. Thus, the applicability of the proposed solution to the coexistence problem is demonstrated.

Multiple fluctuating targets track-before-detect using multi-Bernoulli filter in radar sensor

This paper addresses the detection and tracking of multiple fluctuating targets for a track-before-detect algorithm based on the Multi-Bernoulli (MB-TBD) filter in surveillance radar systems. MB-TBD usually considers target amplitude information and ignores the fact that radar measurements are complex-valued. In this paper, we first propose to utilize phase information to improve the discrimination of targets from noise. More precisely, complex likelihood ratios are used instead of squared modulus measurements likelihood ratios for fluctuations of types Swerling 0, 1, 3. Secondly, the traditional MB-TBD filter cannot solve the problem of coexistence between targets with stronger amplitude and weaker amplitude when multiple fluctuating targets are moving. To address this limitation, an adaptive birth distribution based on joint successive target cancellation and measurement likelihood ratio driven is proposed. Moreover, in order to reduce computational complexity, the Bernoulli components of the same targets are merged after the MB-TBD updating. Finally, the proposed algorithm is implemented using Sequential Monte Carlo technology. The simulation results show that in challenging scenarios, the performance of the improved algorithm is better than the traditional algorithm, and it has a good application prospect.

Modeling road traffic safety based on point patterns of wildlife-vehicle collisions

Wildlife-vehicle collisions represent one of the main coexistence problems that appear between human populations and the environment. In general terms, this affects road safety, wildlife management, and the building of road infrastructures. These accidents are a great danger to the life and safety of car drivers, cause property damage to vehicles, and affect wildlife populations. In this work, we develop a new approach based on algorithms used to obtain minimum paths between vertices in weighted networks to get the optimal (safest) route between two points (departure and destination points) in a road structure based on wildlife-vehicle collision point patterns together with other road variables such as traffic volume (traffic flow information), road speed limits, and vegetation density around roads. For this purpose, we have adapted the road structure into a mathematical linear network as described in the field of Graph Theory and added weights to each linear segment based on the intensity of accidents. Then, the resulting network structure allows us to consider some graph theory methodologies to manipulate and apply different calculations to analyze the network. This new approach has been illustrated with a real data set involving the locations of 491 wildlife-vehicle collisions in a square region (40 km × 40 km) around the city of Lleida, during the period 2010–2014, in the region of Catalonia, North-East of Spain. Our results show the usefulness of our new approach to model road traffic safety based on point patterns of wildlife-vehicle collisions. As such, optimal path selection on linear networks based on wildlife-vehicle collisions can be considered to find the safest path between two pairs of points, avoiding more dangerous routes and even routes containing hotspots of accidents.

Better not talk? A mixed-methods experimental analysis of avoiding sensitive issues in post-conflict settings

Ex-combatants, war victims, and violence-affected community members are typically forced to live together as neighbors in post-conflict settings. Cases all over the world accumulate evidence on the fact that living together after war is a far from a harmonic endeavor, and individuals usually rely on contention mechanisms to keep on with their daily lives while in proximity of former and present-day antagonists. While decades-long academic research has unveiled a series of favorable conditions under which interactions might generate positive effects on intergroup dispositions, they usually prescribe focusing less on touching upon divisive issues, and more on emphasizing in potentially bonding commonalities. By means of a randomized controlled experiment with former war antagonists in Colombia, we set to explore whether avoidance or addressing of the most sensitive issues affecting intergroup relations yield better results in terms of attitude change under favorable conditions. Experimental effects show that perspective-giving protocols are capable of containing polarization tendencies in intergroup discussions even when participants are incentivized to directly address their co-existence problems, while qualitative analysis points out at silences and other avoidance mechanisms as the participants’ key strategies to contain conflict when contentious topics flare up during discussions.

Global dynamics of an oligopoly competition model with isoelastic demand and strategic delegation

In this paper, we propose a dynamic Cournot duopoly game model based on isoelastic demand and strategic delegation. The local stability conditions of each equilibrium point of the system are discussed. We also investigate the influence of parameters on system stability, and we find that with smaller speed of adjustment, relatively large price elasticity, relatively small profit weight coefficient and marginal cost, the duopoly is more stable. Then the problem of coexistence of attractors is studied through the basin of attraction, and it is found that the jump phenomenon in the one-dimensional bifurcation diagram is due to coexistence of attractors. Finally, the structure of the basins of attraction and the global dynamics of the system are analyzed by using critical curves. It is found that when a critical curve or an attractor contact with the boundary of the basin of attraction, global bifurcations occur in the system.

Дескриптивізм і прескриптивізм у китайській традиції кодифікації мов веньян і байхуа

This article analyzes in detail the mechanisms and concepts of the codification of the language norms of the ancient Chinese language in the historical perspective in the light of the problem of coexistence, interaction, development of several immanent linguistic categories. The ratio of descriptive and prescriptive approaches in the processes of codification of the ancient Chinese language, the study of dominant and peripheral approaches to the fixation of linguistic phenomena, the analysis of extralinguistic factors influencing the formation of the language, allow us to understand and explain the linguistic phenomena of the modern Chinese language. The formation of a speech norm through codification processes was caused by a whole range of factors: a political factor (the need for the consolidation of society, the formation of statehood and national identity); socio-economic (urbanization, communication and, as a result, social mobility of the population); cultural (correspondence of the processes of formation and selection of language norms to the ideas of the ruling ethical and philosophical trends, linguistic ideology and the aesthetic canon of their time). In this article, the terms “prescription”, “language codification” are considered in the context of the Chinese philological tradition, primarily in their relationship with the term’s “description”, as well as “language norm”. The codifiers of the ancient Chinese language are represented by various types of dictionaries, and most linguistic studies were carried out to reveal the original meaning of a certain hieroglyph, and not to establish the role of the processes of description and prescription in the selection of linguistic phenomena for the formation of a speech norm. In particular, the study carried out in this article aims to fill this gap and offer answers to questions about the factors of influence and methods for selecting the language norm in the Old Chinese language.

A Potential Game Approach for Decentralized Resource Coordination in Coexisting IWNs

To meet the requirements of various emerging manufacturing applications, multiple Industrial Wireless Networks (IWNs) are employed to operate in the same region. However, the limited communication resources inevitably incur interference in the time and frequency domains, which is known as the coexistence problem. Existing centralized mechanisms suffer from a low computational efficiency in a large-scale network scenario, and the globally shared information cannot be fully obtained in practice. To this end, we first design an incomplete information sharing protocol to clarify the decentralized coordination among coexisting IWNs. We then formulate the coexistence problem as a non-cooperative game, which is proven to be a potential game. In addition, considering the deterministic deadlines of data transmissions in industrial applications, we propose a Deadline-aware Incomplete-Information-based Decentralized Resource Coordination (DIIDRC) algorithm. We also mathematically analyze that the DIIDRC algorithm converges to a collision-free optimal schedule in a resource-sufficient scenario or a nearly-optimal schedule in a resource-insufficient scenario. We conduct extensive simulations to verify the effectiveness of the DIIDRC algorithm. Evaluation results show that the DIIDRC algorithm has obvious superiorities over existing works in terms of the convergence rate and schedulable ratio.

Robust gain-scheduled output feedback H2 controller synthesis with reduced conservativeness: An application to EMS system

This article investigates the design problem of gain-scheduled output feedback (GSOF) [Formula: see text] controller exploiting uncertain scheduling parameters for continuous-time linear parameter-varying (LPV) systems. The problem of coexistence of absolute and proportional uncertainties on the scheduling parameters is considered to address more practical situations. This challenging issue has been tackled by introducing a novel admissible region for the actual and measured scheduling parameters. Furthermore, all the system matrices of the LPV system are assumed to be polynomially dependent on the scheduling parameters with arbitrary degrees. Both Lyapunov and auxiliary matrices are considered to be parameter-dependent. The merit of the proposed method lies in its less conservativeness in comparison with the available approaches. The design method is presented in terms of solutions to a set of parameter-dependent linear matrix inequalities (LMIs) including parameter searches for two scalar values. The application of the provided method on an electromagnetic suspension (EMS) system is considered to demonstrate the applicability and benefits of the proposed approach for practical systems.

Розуміння двосвіту в культурно-історичному аспекті

Research objective. The aim of this article is to identify characteristic models of understanding the two worlds in historical perspective and its impact on the formation and development of simultaneous drama as one of the most optimal for theatrical music of the XX – early XXI centuries. The methodology consists of a system-historical method for considering the phenomenon of the two worlds in art; comparative method for comparative characterization of the influence of the two worlds on the structure and drama of musical works. The scientific novelty is the disclosure of the philosophical and aesthetic category of “double worlds” in various musical genres, mostly theatrical. The dual world is understood as a special type of relationship of different dimensions (personality – the world around us, reality – unreality, etc.). Tracing the genesis of the category of the two worlds from Plato to the present, revealed certain features and its impact on the musical art of the late twentieth – first decades of the twenty-first century. Double worlds influences a special drama, close to the simultaneous type, or the whole work (opera-ballet “Viy” by V. Hubarenko), or its individual sections (“scene of Renata’s hallucinations” in the first act, “scene of knocks” in the second act of the opera “Angel of Fire” by S. Prokofiev). Double worlds subordinates composition, floats to choose from unusual genres – the theater of the absurd in opera “Le Grand Macabre” by D. Ligeti and “Fin de partie” by D. Kurtag. From Romanticism to the present day, there are many examples of literary and theatrical works in which the problem of opposition or coexistence of two different worlds, that is, what is concentrated in the definition of “double worlds”. However, if in literary studies the phenomenon of the dual world is sufficiently reflected, then in musicology there is almost no development of this issue. Conclusions. As a result of this study, it is possible to approach a deeper divergent understanding of the musical world between the prism of the reflection of its historical models. First of all, the two worlds appeal to a certain plot, imagery, close to the mystical, fantastic, phantasmagoric, often occult action.

Problems and prospects of human interaction and artificial intelligence

The article is devoted to the problem interaction of human and artificial intelligence, the ethical aspects of artificial intelligence functioning. The problem of the safe coexistence of man and artificial intelligence is taking on increasing importance. The definition of artificial intelligence and the explanation of the difference between weak, strong artificial intelligence and super-intelligence are given. The first ethical problem of artificial intelligence functioning is the existential question of human redundancy due to the spread of artificial intelligence. The article emphasizes that artificial intelligence, on the one hand, frees a person from certain areas of activity, facilitating their existence, on the other hand, it makes them superfluous in production and in personal life. The second is the problem of responsibility for the actions of artificial intelligence. The article argues for the necessity of human responsibility for the actions of artificial intelligence because artificial intelligence does not have consciousness. The third problem is the intensification of the phenomenon of stupidity in society. Artificial intelligence creates the conditions for the increasing cleverness of some segments of the population and stupidity of others, which can result in even greater mental and property inequality.

Multi-protocol Integration and Intercommunication Technology Based on OPC UA and MQTT

OPC UA and MQTT are widely recognized key technologies for realizing the interconnection and intercommunication of industrial equipment as well as data transmission to the cloud. Based on OPC UA and MQTT, this paper presents a new method to solve the problem of multiple protocols coexistence and information islands in industry. Using the unified name ID to create mappings between OPC UA, MQTT and data acquisition drive, a shared database as data consistency communication medium to support concurrent data reading and writing of OPC UA and MQTT, a data acquisition drive as trigger to realize OPC UA and MQTT data synchronization update. Thus the difficulties of multi-protocol device integration and intercommunication and data uploading to the cloud can be tackled.

Distributed Online Learning for Coexistence in Cognitive Radar Networks

This work addresses the coexistence problem for radar networks. Specifically, we model a network of cooperative, independent, and non-communicating radar nodes which must share resources within the network as well as with non-cooperative nearby emitters. We approach this problem using online Machine Learning (ML) techniques. Online learning approaches are specifically preferred due to the fact that each radar node has no prior knowledge of the environment nor of the positions of the other radar nodes, and due to the sequential nature of the problem. For this task we specifically select the multi-player multi-armed bandit (MMAB) model, which poses the problem as a sequential game, where each radar node in a network makes independent selections of center frequency and waveform with the same goal of improving tracking performance for the network as a whole. For accurate tracking, each radar node communicates observations to a fusion center on set intervals. The fusion center has knowledge of the radar node placement, but cannot communicate to the individual nodes fast enough for waveform control. Every radar node in the network must learn the behavior of the environment, which includes rewards, interferer behavior, and target behavior. Each independent and identical node must choose one of many waveforms to transmit in each Pulse Repetition Interval (PRI) while avoiding <i>collisions</i> with other nodes and interference from the environment. The goal for the network as a whole is to minimize target tracking error, which relies on obtaining high SINR in each time step. Our contributions include a mathematical description of the MMAB framework adapted to the radar network scenario. We conclude with a simulation study of several different network configurations. Experimental results show that iterative, online learning using MMAB outperforms the more traditional sense-and-avoid (SAA) and fixed-allocation approaches.

Multi-Link Operation with Enhanced Synchronous Channel Access in IEEE 802.11be Wireless LANs: Coexistence Issue and Solutions.

Multi-link operation is a new feature of IEEE 802.11be Extremely High Throughput (EHT) that enables the utilization of multiple links using individual frequency channels to transmit and receive between EHT devices. This paper aims to illustrate enhanced multi-link channel access schemes, identify the associated coexistence challenge, and propose solutions. First, we describe the multi-link operation of IEEE 802.11be and how the asynchronous and synchronous channel access schemes facilitate multi-link utilization. Next, we describe the design variants of the synchronous channel access scheme and demonstrate the associated coexistence challenge. Subsequently, we propose four features to address this challenge by assigning penalties to multi-link devices (repicking a backoff count, doubling the contention window size, switching to another contention window set, and compensating the backoff count) as well as five coexistence solutions derived from combinations of these features. Comparative simulation results are provided and analyzed for dense single-spot and indoor random deployment scenarios, demonstrating that the throughput and latency gains of multi-link operation differ between schemes. At the same time, we investigate the coexistence performance of multi-link operation with and without the capability of simultaneous transmission and reception and demonstrate that the proposed solutions mitigate the coexistence problem. In particular, compensating the backoff count achieves the highest coexistence performance among the proposed solutions, with a marginal throughput decrease of multi-link devices. A metric for evaluating both the throughput and latency gains and the coexistence performance of a multi-link channel access scheme using a single value is also proposed.

The Problem of Ukrainian-Polish Coexistence in the Ukrainian Conservative Political Thought of the Interwar Period: Lypynskyi Versus Tomashivskyi in the Framework of Epoch

While studying Polish-Ukrainian relations, outstanding Ukrainian conservative thinkers, namely Vjacheslav Lypynskyi and Stepan Tomashivskyi, focused mainly on the problem of distinguishing the role of Poland in the history of the Ukrainian people and on the issue of orientation towards Poland as a factor in the emergence of the Ukrainian state. The role of Poland in the history of the Ukrainian people, according to conservatives, was twofold. On the one hand, it was Poland that paved the way for Ukraine to Europeanization, providing examples of state-style literature and culture. This constructive role of Poland was especially fruitful in comparison with the Asian influences of Moscow. In this context, the conservatives emphasized that these were the Poles who played a key role in the process of separating Ukrainians from Russia, promoting the rise and establishment of the Cossacks and the Hetmanate, as well as creating the very name “Ukraine”. Conversely, the conservatives negatively assessed the Treaty of Hadiach for Ukraine, which, in their opinion, was very rational, on the one hand, and contributed, on the other hand, to the extermination of the elite and aristocratic democracy, and which disorganized the nobility and made it republican by eliminating its chivalrous essence and adding destructive anarchism instead. The conservatives also sharply assessed the Treaty of Warsaw between Petliura and Pilsudski. Simultaneously, Ukrainian monarchists did not consider Poland a force that could play a role in the creation of the Ukrainian state, although they considered the territorial autonomy of Halychyna under Poland as the first stage in educating the citizens of Western Ukraine in the spirit of the state monarchical idea. They took the position of mutual understanding between Ukrainian conservatives and Halychyna Poles in achieving the autonomy of Ukrainian lands under Poland, although they condemned the concept of a federation of Poland and Ukraine in Halychyna under the conditions put forward by Halychyna Ukrainian National Democrats. Conservatives considered such a strategy doomed to failure without the creation of a conservative territorial group in Halychyna composed of local Poles and Ukrainians. Relying heavily on local Poles not affiliated with metropolitan Warsaw, they placed the main emphasis on the internal organization of the monarchists rather than on external allies, including Poland

A 3-DOF Bionic Waist Joint for Humanoid Robot.

In this study, a 3 degree-of-freedom bionic waist joint was developed with coupled tendon-driven mechanism. This bionic waist joint can not only ensure the safety of the human-robot interface, but also increase the load capacity without increasing the weight. The coupled tendon-driven mechanism enables the motion of each joint to be driven by at least two motors together, and enables a maximum torque of 3 times the maximum motor output torque at each joint. The bionic waist joint has similar kinematic characteristics to a human waist, including degrees of freedom (DOF) and range of motion (ROM). The problem of coexistence of coupling and decoupling in the same rotating joint was solved with a novel mechanism that can promote further versatility of the coupled tendon-driven mechanism. The basic movements and characteristics of the waist was validated in the experiment.