Coexistence Scenarios Research Articles

Unmanned Ship Collision Avoidance Action Plan Deduction Method under Man–Machine Interactive Negotiation in Collision Avoidance Scenarios

With the development of artificial intelligence technology, the future water traffic environment will present a new pattern of coexistence of manned ships and unmanned ships, because unmanned ships are different from manned ships in situation understanding, collision avoidance decision-making, and so on. Therefore, the obstacle avoidance planning between unmanned ships and manned ships becomes extremely complex, and collision avoidance behavior scheme deduction becomes a key step in solving the problems related to situation understanding and collision avoidance decision-making in collision avoidance scenarios. In this paper, the situation understanding of the pilot for different collision avoidance situations is integrated into the dynamic obstacle avoidance model, and an intelligent navigation collision avoidance system is proposed to assist in deducing the collision avoidance action plan of the unmanned ship in the man–machine coexistence scenario. The intelligent navigation collision avoidance system is divided into two parts, namely a ship situation understanding part and a ship obstacle avoidance part, wherein ship situation understanding is used for realizing the transition of the collision state of the unmanned ship in the deduction process by constructing a collision-state set and a behavior decision set by using a finite state machine (FSM). Regarding ship obstacle avoidance, ship velocity obstacle is calculated based on the reciprocal velocity obstacle method (RVO), and the collision avoidance action is selected by using the behavior decision generated by the FSM to realize the dynamic collision avoidance deduction of the unmanned ship. In this study, the validity and effectiveness of the intelligent navigation collision avoidance system proposed in this paper are verified by case studies in a variety of collision avoidance scenarios. The system successfully solves the problem of intelligent collision avoidance planning, provides reliable support for the intelligent collision avoidance of unmanned ships, provides a feasible solution for safety and efficiency in sea navigation, and provides a valuable reference for the design and development of future intelligent navigation collision avoidance systems for ships.

Large Language Model as Parking Planning Agent in the Context of Mixed Period of Autonomous Vehicles and Human-Driven Vehicles

Autonomous vehicles (AVs) are anticipated to revolutionize future transportation, necessitating updates to traffic infrastructure, particularly parking facilities, due to the unique characteristics of AVs compared to Human-Driven Vehicles (HDVs). During the transition period in which AVs and HDVs coexist, adaptable infrastructure is essential to accommodate both vehicle types. Traditional research, typically reliant on complex mathematical models and simulations, faces challenges in adapting to diverse urban settings, requiring substantial time and resources. To address these challenges, a government-level framework was developed, enabling urban planners to quickly and accurately evaluate and optimize existing parking facilities for future AV and HDV coexistence scenarios. The framework integrates a Large Language Model (LLM) to enhance flexibility and efficiency in parking planning throughout the transitional period. Structured guidance is incorporated to enhance decision-making precision and reduce LLM hallucination risks. The flexibility, robustness, and accuracy of the framework were validated through step-by-step and end-to-end testing using real-world datasets. Specifically, the framework achieved 91.1% comprehensiveness and 70.2% consistency in Indicator Selection Module testing, a 68.9% success rate in the Single Indicator Calculation Module, and a 66.7% success rate in end-to-end testing, demonstrating its practical value in supporting cities during AV integration. Finally, the success rates of different LLM agent modules were further explored, along with a comparison of multiple LLMs and an analysis of key issues related to LLM trustworthiness in urban planning applications. The research highlights the potential of LLMs in advancing urban planning processes and optimizing existing infrastructure, contributing to smarter and more adaptable urban environments.

Structural Sensitivity of Chaotic Dynamics in Hastings–Powell’s Model

The classical Hastings–Powell model is well known to exhibit chaotic dynamics in a three-species food chain. Chaotic dynamics appear through period-doubling bifurcation of stable coexistence limit cycle around an unstable coexisting equilibrium point. A specific choice of parameter value leads to a situation, where the chaotic attractor disappears through a collision with an unstable limit cycle originated due to subcritical Hopf-bifurcation around the coexistence equilibrium. As a consequence, the top predator goes to extinction. The main objective of this work is to explore the structural sensitivity of this phenomenon by replacing the Holling-type II functional responses with Ivlev functional responses. In this work, we have shown the existence of two Hopf-bifurcation thresholds and numerically verified the existence of an unstable limit cycle. The model with Ivlev functional responses does not indicate any possibility of extinction of the top predator due to any collision of chaotic attractor with the unstable limit cycle for the chosen range of parameter values. Moreover, the model with Ivlev functional responses depicts an interesting scenario of bistable oscillatory coexistence.

Fluctuation-induced first order transition to collective motion

The nature of the transition to collective motion in assemblies of aligning self-propelled particles remains a long-standing matter of debate. In this article, we focus on dry active matter and show that weak fluctuations suffice to generically turn second-order mean-field transitions into a ‘discontinuous’ coexistence scenario. Our theory shows how fluctuations induce a density-dependence of the polar-field mass, even when this effect is absent at mean-field level. In turn, this dependency on density triggers a feedback loop between ordering and advection that ultimately leads to an inhomogeneous transition to collective motion and the emergence of inhomogeneous travelling bands. Importantly, we show that such a fluctuation-induced first order transition is present in both metric models, in which particles align with neighbors within a finite distance, and in ‘topological’ ones, in which alignment is based on more complex constructions of neighbor sets. We compute analytically the noise-induced renormalization of the polar-field mass using stochastic calculus, which we further back up by a one-loop field-theoretical analysis. Finally, we confirm our analytical predictions by numerical simulations of fluctuating hydrodynamics as well as of topological particle models with either k-nearest neighbors or Voronoi alignment.

Sustainable scenarios in a plants–rhizobacteria–plant consumers system are in risk when biotic or abiotic factors change

The ecological relationship among plants, rhizobacteria and plant consumers has attracted the attention of researchers due to its implications in field crops. It is known that, the rhizosphere is occupied not only by rhizobacteria which grant benefits to the plants but also by bacteria which are detrimental for them. In this work, we construct and analyze a plants–rhizobacteria–plant consumers system. In the modeling process, it is assumed that there is a conditioned interaction between plants and bacteria in the rhizosfera such that there is a mutualistic relationship at low densities of rhizobacteria and the relationship is parasitic or competitive at higher densities of them. Benefits granted by rhizobacteria include mechanisms that increase the plant growth and defense mechanisms against plant consumers. From the analysis of the model and its simplified version, we show that scenarios of coexistence of all populations can occur for a wide range of values of the parameters which describe biotic or abiotic factors; however, these scenarios are in risk since scenarios of exclusion of species can occur simultaneously due to the presence of bistability phenomena. The results obtained can be useful for the decision makers to design interventions strategies on field crops when plant growth-promoting rhizobacteria are used.

Experimental feasibility analysis of quantum/classical coexistence over fibre and free space links

AbstractThe authors present a novel approach to Quantum Key Distribution (QKD) research, emphasising cost‐effectiveness and practicality using a single photon polarisation‐encoded system employing mainly commercial off‐the‐shelf components. This study diverges from previous high‐cost, high‐end setups by exploring the viability of QKD in more accessible and realistic settings. Our approach focuses on practical measurements of the signal‐to‐noise ratio by analysing polarisation‐encoded photonic qubits over various transmission scenarios. The authors introduce a simplified evaluation method that incorporates experimental measurements, such as noise sources and losses, into a semi‐empirical theoretical framework. This framework simulates the standard DS‐BB84 protocol to estimate Secure Key Rates (SKRs), offering an alternative approach on the evaluation of the practical implementation of QKD. Specifically, the authors examine the feasibility of QKD over a 2.2 km intra‐campus fibre link in coexistence scenarios, identifying optimal Wavelength‐Division Multiplexing allocations to minimise Raman noise, achieving an expected SKR of up to 300 bps. Additionally, the authors’ study extends to 40 m indoor and 100 m outdoor Free‐Space Optical (FSO) links using low‐cost components, where the authors recorded Quantum Bit Error Rate (QBER) values below 3.2%, allowing for possible SKRs up to 600 bps even in daylight operation. The converged fibre/FSO scenario demonstrated robust performance, with QBER values below 3.7% and an expected SKR of over 200 bps. Our research bridges the gap between high‐end and economical QKD solutions, providing valuable insights into the feasibility of QKD in everyday scenarios, especially within metropolitan fibre based and FSO links. By leveraging cost‐effective components and a simplified single photon exchange setup, the authors work paves the way for the effortless characterisation of deployed infrastructure, highlighting its potential in diverse settings and its accessibility for widespread implementation.

Joint beam power and pointing management in multi‐beam low earth orbit and low earth orbit co‐existing satellite system

SummaryRecently, the low earth orbit (LEO) satellite has attracted much attention due to its advantages of low latency and construction costs. However, the scarcity of frequency spectrum resources has resulted in these satellites sharing the same spectrum to provide services for ground users. So, challenges such as overlapping beam coverage and inter‐beam interference occur in the multi‐beam LEO satellite coexistence scenario. Therefore, this paper focuses on the issue of interference coexistence in LEO and LEO (LEO–LEO) co‐existing scenario, where the initially established system is the primary system, and the later established system is the secondary system. The interference coexistence problem is modeled as a multi‐objective optimization problem. The joint beam power and pointing management (JBPPM) based on particle swarm optimization (PSO) is proposed. The power control is applied to the LEO satellites in the secondary system to reduce the interference to the primary system user. Meanwhile, beam pointing optimization is adopted by the LEO users in the secondary system to avoid interference from the primary system and ensure the minimum communication ability. The simulation results verify that the proposed technique can adapt to various coexistence conditions and outperform the existing method.

SDN-Based Secure Common Emergency Service for Railway and Road Co-Existence Scenarios

In the near future, there will be a greater emphasis on sharing network resources between roads and railways to improve transportation efficiency and reduce infrastructure costs. This could enable the development of global Cooperative Intelligent Transport Systems (C-ITSs). In this paper, a software-defined networking (SDN)-based common emergency service is developed and validated for a railway and road telecommunication shared infrastructure. Along with this, the developed application is capable of reducing the chances of distributed denial-of-service (DDoS) situations. A level-crossing scenario is considered to demonstrate the developed solution where railway tracks are perpendicular to the roads. Two cases are considered to validate and analyze the developed SDN application for common emergency scenarios. In case 1, no cross-communication is available between the road and railway domains. In this case, emergency message distribution is carried out by the assigned emergency servers with the help of the SDN controller. In case 2, nodes (cars and trains) are defined with two wireless interfaces, and one interface is reserved for emergency data communication. To add the DDoS resiliency to the developed system the messaging behavior of each node is observed and if an abnormality is detected, packets are dropped to avoid malicious activity.

Scenarios for offshore wind co-existence opportunities and trade-offs

This paper introduces the MARCO (MARine CO-existence scenario building) concept for using scenario exploration in stakeholder engagement processes in offshore wind. MARCO builds on spatial analyses using geographic information systems (GIS), and projections over time using system dynamics simulation models. We position the concept within the existing literature on tools for decision support and stakeholder participation, and provide a preliminary status on the spatial baselines, as well as example scenarios for area usage in offshore wind and implications, including risks and co-existence opportunities, on other sectors and nature.

Accurate Localization in LOS/NLOS Channel Coexistence Scenarios Based on Heterogeneous Knowledge Graph Inference

Accurate localization is one of the basic requirements for smart cities and smart factories. In wireless cellular network localization, the straight-line propagation of electromagnetic waves between base stations and users is called line-of-sight (LOS) wireless propagation. In some cases, electromagnetic wave signals cannot propagate in a straight line due to obstruction by buildings or trees, and these scenarios are usually called non-LOS (NLOS) wireless propagation. Traditional localization algorithms such as TDOA, AOA, etc. , are based on LOS channels, which are no longer applicable in environments where NLOS propagation is dominant, and in most scenarios, the number of base stations with LOS channels containing users is often small, resulting in traditional localization algorithms being unable to satisfy the accuracy demand of high-precision localization. In addition, some nonideal factors may be included in the actual system, all of which can lead to localization accuracy degradation. Therefore, the approach developed in this paper uses knowledge graph and graph neural network (GNN) technology to model communication data as knowledge graphs, and it adopts the knowledge graph inference technique based on a heterogeneous graph attention mechanism to infer unknown data representations in complex scenarios based on the known data and the relationships between the data to achieve high-precision localization in scenarios with LOS/NLOS channel coexistence. We experimentally demonstrate a spatial 2D localization accuracy level of approximately 10 meters on multiple datasets and find that our proposed algorithm has higher accuracy and stronger robustness than the state-of-the-art algorithms.

To be or not to be a superpredator: a multidisciplinary assessment of the Iberian lynx in a reintroduction social scenario

Since 2015, following reintroductions, an Iberian lynx population in Vale do Guadiana (Portugal) has been breeding and expanding, bringing changes to both ecosystems and residents’ perceptions. We describe how ecological monitoring, genetic analysis and social surveys contribute to assess this new scenario of coexistence with ecological and social repercussions. Departing from a specific case of a monitored lynx family, we present, for the first time, molecular proof of interspecific competition between lynxes and other carnivores. We assessed and compared knowledge of local key actors about the superpredator effect of the lynx previous to and following reintroduction. Data on damage experienced by livestock breeders with foxes and perceptions about it are integrated here, demonstrating how important this lynx role can be for local actors. We present proof of the killing of two foxes and a genet by lynxes through the amplification of a specific lynx DNA region and other molecular analyses carried out on saliva samples. Local actors, who previously were skeptical about the lynx’s ecological effects, do recognize its effect over other wild carnivores presently. This is a major benefit, since social perceptions have been conditioning the acceptance of the lynx, its future expansion, and the whole process of reintroduction. We also present the first documented case of a natural migrant from Doñana (SW Spain) effectively integrated and reproducing in the Vale do Guadiana population. This case study demonstrates the importance of multidisciplinary knowledge in conservation programmes and how genetics and social surveys provide complementary information for monitoring in reintroduction and, generally, conservation programs of an umbrella species.

Channel Access in Wireless Smart Grid Networks Operating under ETSI Frame-Based Equipment Rules

Smart grid operators seeking to extend their wireless network capacity can use unlicensed bands. However, devices in these shared bands must follow rules such as Listen Before Talk (LBT), standardized by ETSI. In this paper, we focus on the performance of the frame-based equipment (FBE) version of LBT channel access. We design, implement, and validate a fully functional FBE channel access simulator. Next, we conduct an extensive performance analysis of the FBE variants encountered in the literature, focusing on channel efficiency and fairness in upper-bound and coexistence scenarios. Our study leads to several conclusions about the operation of FBE-based devices, including the need for proper configuration of channel access parameters to ensure fairness and optimal performance. We also observe generally poor coexistence among FBE variants: the highest Jain’s fairness index was only 0.88, with an average normalized channel efficiency of 0.76. Therefore, we identify several open research areas in the field, such as the need for further development of parameter adaptation algorithms, the deployment of an external controller to update channel access parameters, and new FBE designs with better coexistence qualities.

A Poisson multi-Bernoulli mixture filter for tracking multiple resolvable group targets

This paper presents a novel Poisson multi-Bernoulli mixture (PMBM) filter for tracking multiple resolvable group targets (MRGT) based on graph theory. Firstly, the number of groups and the relationships between members within the group are modelled by the adjacency matrix. Then, considering that a single dynamic evolution model is insufficient to guarantee stable tracking performance for group targets, the virtual leader-follower model (VLFM) is introduced to predict the evolution trend of unknown and potentially detected targets, respectively. Furthermore, we prove the conjugation of the proposed algorithm with the probability generating functionals (PGF) and give a detailed implementation of the Gaussian mixture (GM). Based on the coexistence scenario of splitting, merging and non-linear motion of the group targets, the simulation results show the effectiveness of the proposed algorithm in comparison with the existing methods.

Potential side effects of the interaction between Phthorimaea absoluta parasitoids: the exotic Dolichogenidea gelechiidivoris and the native Bracon nigricans

The coexistence and efficiency in pest control of introduced and native parasitoids can be challenging. Continuous observations of the cohabitation of parasitoid species could confirm the persistence of the introduced parasitoid in the ecosystem under co-existence scenarios. This study provides an example of such a co-existence for biocontrol of the invasive pest, Phthorimaea absoluta (Meyrick) (Lepidoptera: Gelechiidae). Two parasitoids, the introduced endoparasitoid Dolichogenidea gelechiidivoris (Marsh) (Hymenoptera: Braconidae) and the native ectoparasitoid Bracon nigricans Szépligeti (Hymenoptera: Braconidae) were released in cages containing a tomato plant infested with P. absoluta. Parasitism and killing rate of P. absoluta by both parasitoid species, and the parasitoid and P. absoluta population were monitored weekly. The parasitoid species coexisted for seven weeks in the experimental units. Parasitism by D. gelechiidivoris was significantly affected by the presence of B. nigricans, with 73% and 22% parasitism in the absence and presence of B. nigricans, respectively. Parasitism by B. nigricans was not affected by its co-existence with D. gelechiidivoris. The number of D. gelechiidivoris adults increased eight-fold in five weeks in the absence of B. nigricans, while less than the initial number of adults were present in co-existence with B. nigricans. The P. absoluta infestation declined from the fifth week to 98% lesser than the control in all the treatments, either D. gelechiidivoris or B. nigricans as standalone treatments, as well as in combination. Since B. nigricans negatively affected D. gelechiidivoris population growth, releases of this introduced parasitoid should be considered with caution in areas where B. nigricans occurs.

Perceptions of future teachers of Therapeutic Pedagogy on an intercultural music workshop

ABSTRACT Pupils who are late entrants to the Spanish education system may require a response from Therapeutic Pedagogy. They, as children of immigrants, may have educational needs such as socio-cultural adaptation and the need for respect and non-discrimination of their culture and religion. From an intercultural approach, the music classroom could provide a scenario of coexistence based on social inclusion and cultural exchange. Based on these assumptions, the ‘Caribbean Music Workshop’ was developed within the framework of the subject ‘Physical, plastic and music education and its didactics in special educational needs’. It is a subject of the Therapeutic Pedagogy Major of the Primary Education Teacher Training Degree at the University of Valencia. With the aim of assessing the perceptions of the future Therapeutic Pedagogy teachers about the workshop, at the end of the activity the students filled in a questionnaire with their considerations about the relevance of the intervention and other benefits it could bring to the pedagogical and therapeutic work. After a mixed analysis, the results revealed that the workshop represents a valid intercultural proposal to promote the social inclusion of students who are children of immigrants, as well as to address other educational needs.

Spanish loan verbs in Paraguayan Guaraní: coexistence, replacement, or both?

Abstract Contact linguists have proposed that core borrowing can indicate language attrition – as the loan replaces its native-origin counterpart – while cultural borrowing expands the lexicon (Campbell, Lyle. 2013. Historical linguistics: An introduction, 3rd edn. Edinburgh: Edinburgh University Press; Muysken, Pieter. 2000. Bilingual speech: A typology of code-mixing. Cambridge: Cambridge University Press). However, Tadmor and Haspelmath (Tadmor, Uri & Martin Haspelmath. 2009. Loanwords in the world’s languages: A comparative handbook. Berlin: De Gruyter) found that in core borrowing cases, coexistence of the foreign and the native forms is more common than replacement. In this paper, I explore coexistence and replacement scenarios of Spanish-origin core loan verbs and their native-origin counterparts in Paraguayan Guaraní. These loans have been previously described as instances of code-switching (Estigarribia, Bruno. 2017. Insertion and backflagging as mixing strategies underlying Guaraní-Spanish mixed words. In Bruno Estigarribia & Justin Pinta (eds.), Guaraní linguistics in the 21st century, 315–347. Leiden: Brill; Kallfell, Guido. 2016. ¿Cómo hablan los paraguayos con dos lenguas?: gramática del jopara. Asunción: CEADUC). Tokens of highly frequent native-origin verbs along with their broadly equivalent Spanish-origin loans were extracted from 40 interviews and were correlated with the senses of each verb. Results show that some Spanish verb loans replace its native-origin counterpart to convey only one of its senses, while the native-origin form remains the preferred form to convey the other senses. This specialized use also suggests that these semantically specialized Spanish verb loans are not code-switches but rather integrated lexical items in Guaraní.

Contact force regulation in physical human-machine interaction based on model predictive control

AbstractWith increasing attention to physical human-machine interaction (pHMI), new control methods involving contact force regulation in collaborative and coexistence scenarios have spread in recent years. Thanks to its internal robustness, high dynamic performance, and capabilities to avoid constraint violations, a Model Predictive Control (MPC) action can pose a viable solution to manage the uncertainties involved in those applications. This paper uses an MPC-driven control method that aims to apply a well-defined and tunable force impulse on a human subject. After describing a general control design suitable to achieve this goal, a practical implementation of such a logic, based on an MPC controller, is shown. In particular, the physical interaction considered is the one occurring between the body of a patient and an external perturbation device in a dynamic posturography trial. The device prototype is presented in both its hardware architecture and software design. The MPC-based main control parameters are thus tuned inside hardware-in-the-loop and human-in-the-loop environments to get optimal behaviors. Finally, the device performance is analyzed to assess the MPC algorithm’s accuracy, repeatability, flexibility, and robustness concerning the several uncertainties due to the specific pHMI environment considered.

Synthetic biology enabling a shift from domination to partnership with natural space

Synthetic biology is a field of science that examines biological systems through the lens of engineering with the explicit objective of rationally designing live objects for either fundamental or biotechnological purposes. Yet, the same conceptual frame also embodies its exact counterpart: the biologization of engineering, i.e., looking at rationally designed systems through the lens – and with the tools – of biology and evolution. Such a creative tension between technology-driven design and biological processes has one of the most conspicuous battlegrounds in modern architecture. Such an edge occurs in a time dominated by the evidence of climate change, ramping environmental deterioration, and the ensuing instability and mass migrations. The most recent influences of biology in architecture have moved from the adoption of biologically inspired shapes and forms in many types of buildings to the incorporation of new biomaterials (often functionalized with qualities of interest) as assembly blocks, to the amalgamation of live materials with other construction items. Yet, the possibility opened by synthetic biology to redesign biological properties à la carte, including large-scale developmental programs, also unlocks the opportunity to rethink our interplay with space, not as one more step in the way of domination, but as a win-win conversation with the natural environment. While various contemporary architectural tendencies clearly move in that direction, we propose a radical approach–exemplified in the so-called Biosynthetic Towers Project–in which complex buildings are designed and erected entirely through biological programming rather than assembled through standard construction technology. To make this scenario a reality, we need not only tackle a dedicated research agenda in the synthetic biology side, but also develop a new attentive mindset toward the environment, not as a space to be conquered for our exclusive own sake, but as one scenario of sustainable co-existence with the rest of the natural world.

Misbehavior Detection in Wi-Fi/LTE Coexistence Over Unlicensed Bands

We address the problem of detecting misbehavior in the coexistence between LTE and Wi-Fi systems operating in the 5 GHz U-NII unlicensed bands. We define selfish misbehavior strategies for the LTE that can yield an unfair share of the spectrum resources. Such strategies are based on manipulating the operational parameters of the LTE-LAA standard. Prior methods for detecting misbehavior in homogeneous settings are not applicable in a spectrum sharing scenario because the devices of one system cannot decode the transmissions of another. We develop implicit sensing techniques that can accurately estimate the operational parameters of LTE transmissions under various topological scenarios and {\em without decoding.} These techniques apply correlation-based signal detection to infer the required information. Our techniques are validated through experiments on a USRP testbed. We further apply a statistical inference framework for determining deviations of the LTE behavior from the coexistence etiquette. By characterizing the detection and false alarm probabilities, we show that our framework yields high detection accuracy at a very low false alarm rate. Although our methods focus on detecting misbehavior of the LTE system, they can be generalized to detect Wi-Fi misbehavior and to other coexistence scenarios.

Time Hopping: An Efficient Technique for Reliable Coexistence of TSCH-Based IoT Networks

Escalation in the use of Internet-of-Things (IoT) devices gives rise to the number of networks operating in the license-free 2.4 GHz frequency band. This prepares the ground for networks to experience interference from coexisting networks and thus performance degradation. Time Slotted Channel Hopping (TSCH), as an operational medium access mode of the IEEE 802.15.4 technology, was introduced to ensure the reliability of IoT networks when they undergo coexistence. It uses frequency hopping as a protective strategy against long-term packet losses due to interference. However, when several independent TSCH networks coexist, they are prone to interfere with one another. In extreme scenarios, coexisting TSCH networks may block links of one another for an extended duration of time, leading to application failure. In this paper, we propose a novel technique called time hopping to secure the reliability of coexisting TSCH networks. The developed technique synchronously and periodically alters the timing of nodes within a TSCH network to avoid coexisting TSCH networks from getting stuck in extreme coexistence scenarios and long-term continuous collisions. We evaluate the effectiveness of the proposed technique through extensive simulations. The results clearly show that the proposed time hopping technique substantially improves the worst-case inter-network collision ratio, with as much as 50% improvement in some tested scenarios. The implementation of the technique is very simple, with almost no communication or computation overhead for the constrained wireless nodes; it is done and tested on real nodes for proof of concept.