Artykuły w czasopismach na temat „Hybrid Hierarchical Key Agreement Scheme”

Multi-operator wireless mesh networks (WMNs) have attracted increasingly attentions as a low-cost accessing approach for future large-scale mobile network. Security and privacy are two important objectives during the deployment of multi-operator WMNs. Despite the necessity, limited literature research takes both privacy and user experience into account. This motivates us to develop PPS, a novel privacy-preserving security scheme, for multi-operator WMNs. On one hand, most of the privacy needs are satisfied with the hybrid utilization of a tri-lateral pseudonym and a ticket based on proxy blind signature. On the other hand, the sophisticated unlinkability is implemented where mobile user is able to keep his pseudonym unchanged within the same operator in order to gain better user experience. PPS is presented as a suite of authentication and key agreement protocols built upon the proposed three-tire hierarchical network architecture. Our analysis demonstrates that PPS is secure and outperforms other proposal in terms of communication and computation overhead.

Wireless sensor networks are widely applied in various applications. But due to the resource-constrained sensor nodes and the malicious attacks, the traditional key management schemes are not suitable for the network. Contraposing the particularities, many relevant key management schemes are developed for WSNs the network. Based on the framework of WSNs, existing schemes can be classified into two categories: flat distributed architecture and hierarchical architecture. In this paper, a hybrid key management scheme for wireless sensor network is proposed by combining the distributed architecture and the hierarchical architecture. Based on the modified version of Dus matrix construction, this scheme can apply in WSNs with the network topology changes. Compared with existing key management schemes, this scheme can provide sufficient security, nicer key connectivity and low key storage overhead.

Nowadays, sensor networks are one of the hottest scientific issues. A lot of research has been done to improve their efficiency. Wireless Sensor Networks (WSN) are applied as an important and efficient technology in many industries such as military operations, security systems, intelligent transportation systems, medics, agriculture, and many others. Key agreement is a challenging point in the security of these networks. Sensor nodes connect to each other using cryptography techniques, however, use of the classic key management techniques such as key distribution center is inefficient because of resource-constrained nature of the sensor nodes. This paper proposes a hierarchical multiple key agreement scheme. In the proposed scheme, two nodes can produce multiple session keys, just with only one run of the key agreement protocol by two nodes in the hierarchical system. As well as its efficiency, this new scheme is based on identity and non-interactive protocol. Being zero-knowledge proof is another advantage of the scheme.

Wireless Health Monitoring Systems (WHMS) have potential to change the way of health care and bring numbers of benefits to patients, physicians, hospitals, and society. However, there are crucial barriers not only to transmit the biometric information but also to protect the privacy and security of the patients’ information. The key agreement between two entities is an essential cryptography operation to clear the barriers. In particular, the noninteractive hierarchical key agreement scheme becomes an attractive direction in WHMS because each sensor node or gateway has limited resources and power. Recently, a noninteractive hierarchical key agreement scheme has been proposed by Kim for WHMS. However, we show that Kim’s cryptographic scheme is vulnerable to the collusion attack if the physicians can be corrupted. Obviously, it is a more practical security condition. Therefore, we proposed an improved key agreement scheme against the attack. Security proof, security analysis, and experimental results demonstrate that our proposed scheme gains enhanced security and more efficiency than Kim’s previous scheme while inheriting its qualities of one-round communication and security properties.

Hierarchical key assignment scheme is an efficient cryptographic method for hierarchical access control, in which the encryption keys of lower classes can be derived by the higher classes. Such a property is an effective way to ensure the access control security of Internet of Things data markets. However, many researchers on this field cannot avoid potential single point of failure in key distribution, and some key assignment schemes are insecure against collusive attack or sibling attack or collaborative attack. In this paper, we propose a hierarchical key assignment scheme based on multilinear map to solve the multigroup access control in Internet of Things data markets. Compared with previous hierarchical key assignment schemes, our scheme can avoid potential single point of failure in key distribution. Also the central authority of our scheme (corresponding to the data owner in IoT data markets) does not need to assign the corresponding encryption keys to each user directly, and users in each class can obtain the encryption key via only a one-round key agreement protocol. We then show that our scheme satisfies the security of key indistinguishability under decisional multilinear Diffie-Hellman assumption. Finally, comparisons show the efficiency of our scheme and indicates that our proposed scheme can not only resist the potential attacks, but also guarantee the forward and backward security.

Establishing secure access and communications in a hierarchical mobile IPv6 (HMIPv6) network, when a mobile node is roaming into a foreign network, is a challenging task and has so far received little attention. Existing solutions are mainly based on public key infrastructure (PKI) or identity-based cryptography (IBC). However, these solutions suffer from either efficiency or scalability problems. In this paper, we leverage the combination of PKI and certificate-based cryptography and propose a hierarchical security architecture for the HMIPv6 roaming service. Under this architecture, we present a mutual authentication protocol based on a novel cross-certificate and certificate-based signature scheme. Mutual authentication is achieved locally during the mobile node?s handover. In addition, we propose a key establishment scheme and integrate it into the authentication protocol which can be utilized to set up a secure channel for subsequent communications after authentication. As far as we know, our approach is the first addressing the security of HMIPv6 networks using such a hybrid approach. In comparison with PKI-based and IBCbased schemes, our solution has better overall performance in terms of authenticated handover latency.

Advance development in wireless sensor network (WSN) has offered tremendous applications in various fields. WSN consists of tiny sensors with unique features, capable of processing the sensed data and are resource constrained. WSN provides robust connection between objects to share information via wireless medium. Despite the significance, WSN face several issues such as more energy consumption, bandwidth constrain and security. Due to open environment and wireless medium secure data transmission within WSN is a critical issue, thus to cope with WSN applications a robust security development is required. Cluster based hierarchical network guarantees energy efficient over flat network. However existing security scheme employs high computational cryptographic functions which consumes more energy and has higher computational overhead. In this work we propose energy efficient hybrid secure key management scheme (EEHSKM) for secure communication from cluster head to base station. This scheme aims to optimize public key cryptographic steps and utilizes symmetric key cryptographic operations which extensively reduce energy consumption and ensures secure communication. The simulation results are evaluated to achieve QoS metrics.

Abstract Most of the existing IoT communication encryption schemes have the following two problems: the sensor side needs to perform complex bilinear mapping calculations; most schemes separate key agreement and data encryption, which increases the user’s computational burden and management difficulty. This paper proposes a lightweight IoT hybrid signature scheme based on bilinear mapping. In terms of transmission efficiency, the calculation process of the bilinear map is transferred to the initialization phase of the system. The sensor side only needs low-cost operations such as hash mapping and exponential operation, which reduces the overall computing cost of the solution. In terms of security, the mathematical difficulty caused by the bilinear mapping calculation in the initialization phase is used to ensure the security of data transmission. In solving the problem of key management, the scheme uses the semi-trusted key generation center (KGC) and sensor ID to generate user session keys and data keys, which solves the public key authentication and key escrow problems of massive sensors in the Internet of Things.

In cryptographic system so as to manage the group of members, the group key management protocol is used and it also should provide the security to the group of members which means the communication among the members will be done in secure manner. Broadcast Encryption (BCE) provides a key it arise common for all the members in the group during the encryption and all the associated members can decipher the message with the same mutual key but cannot stop decrypt the message by individuals. Broadcast encipher algorithm sends a secure transmit note to the entire members with the distributed key to decrypt the message with trusted third party. The conventional BE scheme fully relies on third party reliable key generator server machine, the responsibility of the third party server is to generating the undisclosed deciphering keys for the entire collection members and the group members are responsible for decrypt the messages which are encrypted under a common encrypted key. The purpose of Group Key Accord (GKAP) protocol is for negotiate all the assembly members and designing a familiar encryption key through the network. With the GKAP the group members are responsible for generating universal encipher key and it permits simply the group people to decrypt the cipher text which is encrypted by group members by using the shared encryption key but this GKA protocol it is not possible to exclude any members from the group to decrypt the cipher text shared under the common encryption key. In this paper we will combine these two techniques to produce a novel approach called as the Hybrid Broadcast Encryption (HBCE). In this innovative primeval all the cluster of participants agree and produces a widespread encipher key but though each individual having their own decipher key, So that the sender by looking the encryption key he will bound the deciphering to limited members for his abundance.

A secure data collection in wireless multimedia sensor networks (WMSNs) has given attention to one of security issues. WMSNs pose unique security challenges due to their inherent limitations in communication and computing, which makes vulnerable to various attacks. For the energy efficiency, WMSNs adopt mobile sinks to collect data from sensor nodes. Thus, how to gather data securely and efficiently is an important issue WMSNs. In this paper, we propose a secure energy efficient data collection scheme over WMSNs, which are based on Bilinear pairing and symmetric key cryptosystem. First of all, we devise a security model based on a hierarchical key structure for the security mechanisms, authentication, key agreement, confidentiality, and integrity. Based on the model, we propose a secure energy efficient data collection scheme, which could establish secure session in one round. The proposed scheme could efficiently remedy security and efficiency problems in the previous data collection schemes over WMSNs. It has only about 18% of overhead for the security but also has energy efficiency compared with the other related schemes.

The node–edge–cloud collaborative computation paradigm has introduced new security challenges to data sharing. Existing data-sharing schemes suffer from limitations such as low efficiency and inflexibility and are not easily integrated with the node–edge–cloud environment. Additionally, they do not provide hierarchical access control or dynamic changes to access policies for data privacy preservation, leading to a poor user experience and lower security. To address these issues, we propose a data-sharing scheme using attribute-based encryption (ABE) that supports node–edge–cloud collaborative computation (DS-ABE-CC). Our scheme incorporates access policies into ciphertext, achieving fine-grained access control and data privacy preservation. Firstly, considering node–edge–cloud collaborative computation, it outsources the significant computational overhead of data sharing from the owner and user to the edge nodes and the cloud. Secondly, integrating deeply with the “node–edge–cloud” scenario, the key distribution and agreement between all entities embedded in the encryption and decryption process, with a data privacy-preserving mechanism, improve the efficiency and security. Finally, our scheme supports flexible and dynamic access control policies and realizes hierarchical access control, thereby enhancing the user experience of data sharing. The theoretical analysis confirmed the security of our scheme, while the comparison experiments with other schemes demonstrated the practical feasibility and efficiency of our approach in node–edge–cloud collaborative computation.

This paper addresses the path planning and control of multiple colonies/clusters that have unmanned aerial vehicles (UAV) which make a network in a hazardous environment. To solve the aforementioned issue, we design a new and novel hybrid algorithm. As seen in the mission requirement, to combine the Maximum-Minimum ant colony optimization (ACO) with Vicsek based multi-agent system (MAS) to make an Artificially Intelligent (AI) scheme. In order to control and manage the different colonies, UAVs make a form of a network. The designed method overcomes the deficiencies of existing algorithms related to controlling and synchronizing the information globally. Furthermore, our designed architecture bounds, lemmatizes the pheromone, and finds the best ants which then make the most optimized path. The key contribution of this study is to merge two unique algorithms into a hybrid algorithm that has superior performance than both algorithms operating separately. Another contribution of the designed method is the ability to increase the number of individual agents inside the colony or the number of colonies with a good convergence rate. Lastly, we also compared the simulation results with the non-dominated sorting genetic algorithm II (NSGA-II) in order to prove the designed algorithm has a better convergence rate.

Microgrids (MGs) are capable of playing an important role in the future of intelligent energy systems. This can be achieved by allowing the effective and seamless integration of distributed energy resources (DERs) loads, besides energy-storage systems (ESS) in the local area, so they are gaining attraction worldwide. In this regard, a DC MG is an economical, flexible, and dependable solution requiring a trustworthy control structure such as a hierarchical control strategy to be appropriately coordinated and used to electrify remote areas. Two control layers are involved in the hierarchy control strategy, including local- and global-control levels. However, this research focuses mainly on the issues of DC MG’s local control layer under various load interruptions and power-production fluctuations, including inaccurate power-sharing among sources and unregulated DC-bus voltage of the microgrid, along with a high ripple of battery current. Therefore, this work suggests developing local control levels for the DC MG based on the hybrid particle swarm optimization/grey wolf optimizer (HPSO–GWO) algorithm to address these problems. The key results of the simulation studies reveal that the proposed control scheme has achieved significant improvement in terms of voltage adjustment and power distribution between photovoltaic (PV) and battery technologies accompanied by a supercapacitor, in comparison to the existing control scheme. Moreover, the settling time and overshoot/undershoot are minimized despite the tremendous load and generation variations, which proves the proposed method’s efficiency.

Due to high efficiency and good scalability, hierarchical hybrid P2P architecture has drawn more and more attention in P2P streaming research and application fields recently. The problem about super peer selection, which is the key problem in hybrid heterogeneous P2P architecture, is becoming highly challenging because super peers must be selected from a huge and dynamically changing network. A distributed super peer selection (SPS) algorithm for hybrid heterogeneous P2P streaming system based on evolutionary game is proposed in this paper. The super peer selection procedure is modeled based on evolutionary game framework firstly, and its evolutionarily stable strategies are analyzed. Then a distributedQ-learning algorithm (ESS-SPS) according to the mixed strategies by analysis is proposed for the peers to converge to the ESSs based on its own payoff history. Compared to the traditional randomly super peer selection scheme, experiments results show that the proposed ESS-SPS algorithm achieves better performance in terms of social welfare and average upload rate of super peers and keeps the upload capacity of the P2P streaming system increasing steadily with the number of peers increasing.

Wireless sensor networks (WSNs) have developed during the past twenty years as a result of the accessibility of inexpensive, short-range, and simple-to-deploy sensors. A WSN technology sends the real-time sense information of a specific monitoring environment to a backend for processing and analysis. Security and management concerns have become hot topics with WSN systems due to the popularity of wireless communication channels. A large number of sensors are dispersed in an unmonitored medical environment, making them not safe from different risks, even though the information conveyed is vital, such as health data. Due to the sensor′s still limited resources, protecting information in WSN is a significant difficulty. This paper presents a hierarchical key management method for safeguarding heterogeneousWSNs on hybrid energy-efficient distributed (HEED) routing. In the proposed method, the Bloom scheme is used for key management and a pseudo-random number generator (PRNG) to generate keys in an efficient method to keep sensor resources. In addition, using cipher block chaining-Rivest cipher 5 (CBC-RC5) in this method achieved cryptography goals such as confidentiality. A comparison is made between the proposed and existing methods such as dynamic secret key management (DSKM) and smart security implementation (SSI) under the same circumstance to determine the performance of the new method. The data transmission in WSN consumes about 71 percent of a sensor′s energy, while encryption computation consumes only 2 percent. As a result, our method reduces the frequency with which data transmissions are made during the key management process. The simulation findings demonstrated that, in comparison to earlier techniques, the proposed method is significantly more secure, flexible, scalable, and energy-efficient. Our proposed method is also able to prevent classifications of node capture attacks.

As a key component of ubiquitous computing, the wireless body area network (WBAN) can be used in a variety of disciplines, including health monitoring. Our everyday routines have been transformed by wearable technology, which has changed the medical industry and made our lives more convenient. However, the openness of the wireless network has raised concerns about the privacy and security of patient’s data because of the latent threat imposed by attackers. Patients’ sensitive data are safeguarded with authentication schemes against a variety of cyberattacks. Using pulse signals and a lightweight cryptographic approach, we propose a hybrid, anonymous, authentication scheme by extracting the binarized stream (bio-key) from pulse signal. We acquired 20 different sample signals to verify the unpredictability and randomness of keys, which were further utilized in an authentication algorithm. Formal proof of mutual authentication and key agreement was provided by the widely known BAN logic, and informal verification was provided by the Automated Validation of Internet Security Protocol and Applications (AVISPA) tool. The performance results depicted that storage cost on the sensor side was only 640 b, whereas communication cost was 512 b. Similarly, the computation time and energy consumption requirements were 0.005 ms and 0.55 µJ, respectively. Hence, it could be asserted that the proposed authentication scheme provided sustainable communication cost along with efficient computation, energy, and storage overheads as compared to peer work.

Healthcare diagnosis records are essential as they establish perpetual reports on the health of patients. These records are in nature meant to be kept confidential. It is for this reason that medical data should be secured before transmission. Steganography and cryptography are old concepts used to secure communications. Steganography is hiding data into a carrier, for instance, images, videos, texts, and files. It seeks to hide the existence of communications. Cryptography is communication in deciphering secret writings or ciphers. In our privacy-preserving scheme for healthcare records, a hybrid approach is used to ensure the maximum multi-level security of medical records before transmission. The proposed system utilizes AES-128 which is a symmetric key encryption algorithm to scramble the data. As compared to asymmetric key encryption, symmetric key encryption is faster as only one key is used for both encryption and decryption. To resolve the problem of key distribution that plagues symmetric cryptosystems, the proposed system makes use of the Diffie-Hellman key exchange algorithm for key agreement. In this way, the encryption essentials are securely exchanged before the actual transmission of the date. To ensure efficient and optimal steganography throughput, the Least significant bit (LSB) which involves the hiding of information in the most repetitive bits of each pixel of an image was implemented for steganography. The technique was chosen because the level of distortion made to the image is low hence the image quality change is minimal. As such, the resultant robust system, is highly impeccable, utilises efficient compression, and has improved capacity which are all desirable features for securing medical health records.

A built environment with high-quality esthetic expression can positively contribute to key agendas of urban development. Environmental design is the design of physical environments that mainly respond to people’s behavioral needs and sensory preferences based on environment–behavior relations. Practitioners in this industry often work on esthetic quality improvement. Although previous studies have provided valuable knowledge about important elements of built environment esthetic expression, limited research efforts have been devoted to building a systematic framework that comprises key evaluation elements with high local adaptability and the influence relationships among them. The standards and preferences of esthetic expression in environmental design scheme evaluation are context-based. Providing an effective way to clarify evaluation elements with high local adaptability and the relationships among them may help reduce ambiguity, enhance consensus, and increase efficiency in the decision-making process. Therefore, this study adopted the esthetic expression evaluation of environmental design in China as an example and produced a hybrid decision analysis model by integrating the fuzzy Delphi method (FDM), exploratory factor analysis (EFA), analytic hierarchy process (AHP), and decision-making trial and evaluation laboratory (DEMATEL) method to evaluate the esthetic expression of environmental design schemes. A hierarchical evaluation framework composed of 5 dimensions and 18 evaluation elements was constructed in this study. The key design elements under each dimension and the influence relationships among them were also identified. This paper offers insights into the theoretical investigation and practical development of a systematic evaluation of the esthetic expression of environmental design schemes.

Heterogeneous network (HetNet) is considered to be the most promising approach for increasing communication capacity. However, HetNet control problems are difficult due to their intertier interference. Recently, the enhanced intercell interference coordination (eICIC) technology is introduced to offer several benefits, including a more equitable traffic load distribution across the macro and embedded small cells. In this paper, we design a new resource allocation scheme for the eICIC-based HetNet. Our proposed scheme is formulated as a joint cooperative game to handle conflicting requirements. By adopting the ideas of Kalai and Smorodinsky solution (KSS), multicriteria Kalai and Smorodinsky solution (MCKSS), and sequential Raiffa solution (SRS), we develop a hybrid control algorithm for an adaptive resource sharing between different base stations. To effectively adjust the eICIC fraction rates, the concepts of MCKSS and SRS are applied in an interactive manner. For mobile devices in the HetNet, the assigned resource is distributed by using the idea of KSS. The key insight of our algorithm is to translate the originally competitive problem into a hierarchical cooperative problem to reach a socially optimal outcome. The main novelty of our approach is its flexibility to reach a reciprocal consensus under dynamic HetNet environments. Exhaustive system simulations illustrate the performance gains along different dimensions, such as system throughput, device payoff, and fairness among devices. The superiority of our proposed scheme is fully demonstrated in comparison with three other existing eICIC control protocols.

In this paper, we propose a novel family of semi-implicit hybrid finite volume/finite element schemes for computational fluid dynamics (CFD), in particular for the approximate solution of the incompressible and compressible Navier-Stokes equations, as well as for the shallow water equations on staggered unstructured meshes in two and three space dimensions. The key features of the method are the use of an edge-based/face-based staggered dual mesh for the discretization of the nonlinear convective terms at the aid of explicit high resolution Godunov-type finite volume schemes, while pressure terms are discretized implicitly using classical continuous Lagrange finite elements on the primal simplex mesh. The resulting pressure system is symmetric positive definite and can thus be very efficiently solved at the aid of classical Krylov subspace methods, such as a matrix-free conjugate gradient method. For the compressible Navier-Stokes equations, the schemes are by construction asymptotic preserving in the low Mach number limit of the equations, hence a consistent hybrid FV/FE method for the incompressible equations is retrieved. All parts of the algorithm can be efficiently parallelized, i.e., the explicit finite volume step as well as the matrix-vector product in the implicit pressure solver. Concerning parallel implementation, we employ the Message-Passing Interface (MPI) standard in combination with spatial domain decomposition based on the free software package METIS. To show the versatility of the proposed schemes, we present a wide range of applications, starting from environmental and geophysical flows, such as dambreak problems and natural convection, over direct numerical simulations of turbulent incompressible flows to high Mach number compressible flows with shock waves. An excellent agreement with exact analytical, numerical or experimental reference solutions is achieved in all cases. Most of the simulations are run with millions of degrees of freedom on thousands of CPU cores. We show strong scaling results for the hybrid FV/FE scheme applied to the 3D incompressible Navier-Stokes equations, using millions of degrees of freedom and up to 4096 CPU cores. The largest simulation shown in this paper is the well-known 3D Taylor-Green vortex benchmark run on 671 million tetrahedral elements on 32,768 CPU cores, showing clearly the suitability of the presented algorithm for the solution of large CFD problems on modern massively parallel distributed memory supercomputers.

AbstractFaced with a pressing demand for eldercare workers, Japan signed Economic Partnership Agreements (EPAs) to recruit workers from Southeast Asian countries. The EPA limits the employment period for migrant workers, unless they successfully pass the healthcare licensure examination in Japanese. Therefore, they receive on-the-job training and prepare for the examination, making their host institutions partly responsible for assisting the training and exam preparation. In this system, migrants’ Japanese ability, tested against a strict standard, is the key to their being successfully accepted as good workers. Migrant workers and their employers are thus important actors in a neoliberal logic in which mastering a specific language practice and demonstrating it on standardized tests is deemed important for one’s social mobility. To analyse how this logic is realised in a healthcare workplace, this paper draws on fieldwork data in an eldercare home employing EPA workers. The operation scheme of the EPA and institutional policy will be highlighted as underlying mechanisms for the creation of neoliberal subjects. I argue these measures primarily support the hierarchical relationships between Japanese and non-Japanese, and between employer and employee. I also discuss consequential ways in which on-the-job training has differentially impacted employment trajectories of the migrant workers.

The fifth-generation (5G) mobile communication technology has already deployed commercially and become a global research focus. The new features of 5G include unlimited information exchange, a large variety of connections with independent energy, and diversified high transmission rate services. Collective synergy of services is expected to change the way of life and future generations and introduce new converged services to the ICT industry. Different application services have to meet differentiated security demands. From the perspective of security, in order to support the multiservice of 5G services, it is necessary to consider the new security mechanism driven by the service. Based on 5G massive data stream, the 5G system can provide customized real-world services for potential users and reduce the user experience gap in different scenarios. However, 3GPP Extensible Authentication Protocol (EAP), which is the present entity authentication mechanism for the 5G service layer, is only an individual authentication architecture and unable to fulfill the flexible security objectives of differentiated services. In this paper, we present a new hierarchical identity management framework as well as an adaptable and composable three-factor authentication and session key agreement protocol for different applications in 5G multiservice systems. Finally, we propose an authorization process by combining with the proposed three-factor authentication mechanism and Service-Based Architecture (SBA) proposed by the 3GPP committee. The proposed mechanism can concurrently provide diverse identity authentication schemes corresponding to four different security levels by easily splitting or assembling three-factor authentication protocol blocks. The proposed scheme can be simultaneously applied to a variety of applications to improve the efficiency and quality of service and reduce the complexity of the whole 5G multiservice system, instead of designing or adopting several different authentication protocols. The performance evaluation results indicate that the proposed scheme can guarantee the multiple security of the system with ideal efficiency.

In software-defined wireless sensor networks (SDWSNs), topology control is a fundamental procedure to maintain the global network topology. However, the open wireless channels of SDWSNs make it possible for an attacker to eavesdrop, replay, or modify the topology messages, thus posing a great threat to the network operations. The security of SDWSN topology control has not received enough attention yet. Identity-based cryptography (IBC) may be fitter for SDWSNs due to its capability of generating the public key from the node identity directly, compared with traditional cryptography. In particular, identity-based combined encryption and signature cryptography (IBCES) could encrypt and sign the messages using the same identity. As such, to secure the confidentiality, integrity, and authentication of topology information, we put forward a secure topology control mechanism based on IBCES. First, we use an identity-based encryption authenticated key agreement scheme to implement the authentication of neighbor nodes and hop-to-hop verification via secure neighbor discovery and topology discovery processes. Then through the node admission and key establishment process, the end-to-end secure channels are established between the nodes, sinks, and Controller. Finally, secure topology collection and management processes supporting flat and hierarchical network structures are designed to guarantee the security of topology information. Theoretical analysis shows that our methods could satisfy the security needs of SDWSN topology control and resist several security attacks. The experimental results indicate that our mechanisms are suitable for SDWSNs.

Confidentiality and efficient bandwidth utilization require a combination of compression and encryption of digital images. In this paper, a new method for joint image compression and encryption based on set partitioning in hierarchical trees (SPIHT) with optimized Kd-tree and multiple chaotic maps was proposed. First, the lossless compression and encryption of the original images were performed based on integer wavelet transform (IWT) with SPIHT. Wavelet coefficients undergo diffusions and permutations before encoded through SPIHT. Second, maximum confusion, diffusion and compression of the SPIHT output were performed via the modified Kd-tree, wavelet tree and Huffman coding. Finally, the compressed output was further encrypted with varying parameter logistic maps and modified quadratic chaotic maps. The performance of the proposed technique was evaluated through compression ratio (CR) and peak-signal-to-noise ratio (PSNR), key space and histogram analyses. Moreover, this scheme passes several security tests, such as sensitivity, entropy and differential analysis tests. According to the theoretical analysis and experimental results, the proposed method is more secure and decreases the redundant information of the image more than the existing techniques for hybrid compression and encryption.

Reusing wastewater in agriculture has attracted increasing attention as a strategy to support the transition towards the circular economy in the water and agriculture sector. As a consequence, there is great interest in solutions for governing the transactions and interdependences between the associated value chains. This paper explores the institutions and governance structures for coordinating transactions and interdependences between actors in linked value chains of wastewater treatment and crop production. It aims to analyze how transactions and interdependences shape the governance structures for reusing wastewater at the local level. A transaction costs analysis based on data from semi-structured interviews and a questionnaire is applied to the agricultural wastewater reuse scheme of the Wastewater Association Braunschweig (Germany). The results show that different governance structures are needed to match with the different properties and requirements of the transactions and activities between linked value chains of wastewater treatment and crop production. Interdependences resulting from transactions between wastewater providers and farmers increase the need for hybrid and hierarchical elements in the governance structures for wastewater reuse. The authors conclude that aligning governance structures with transactions and interdependences is key to efficiently governing transactions and interdependences between linked value chains in a circular economy.

Assembled methods play a critical role in the construction of precast concrete structures. However, conventional dry-connections-like sleeve grouting joints in precast concrete structures lagged at a low construction and management efficiency with poor quality control. In this study, a novel steel joint for precast reinforced concrete beam-column components is proposed to improve constructability. New joints transform the assembled method from reinforced concrete members into a steel structure by setting a pre-embedded steel connector at both ends of reinforced concrete beams and columns, showing outstanding economic, durability, and fire resistance capabilities. The construction process, construction efficiency, economy, and energy consumption were discussed based on the material, structure, and construction hybrid characteristics. Numerical simulation and structural health monitoring methods are used to monitor and evaluate the deformation and stress state of the proposed system in the whole construction process, so as to optimize the construction scheme and ensure safe and orderly construction. The results reveal that the FEA-simulated values of key building components during construction are in good agreement with the actual monitoring values, which verifies the feasibility of the FEM models and provides a guarantee for construction safety; the construction period of the proposed assemble system is reduced by approximately 56% and 40%, compared with the conventional reinforced concrete frame structure and cast-in-place joints in the precast concrete frame structure, respectively. Meanwhile, the energy consumption of buildings decreases by 20%. This research provides a theoretical basis for the design, calculation, and application of assembled precast structural systems.

Soil moisture is a key variable in Earth systems, controlling the exchange of water andenergy between land and atmosphere. Thus, understanding its spatiotemporal distribution andvariability is important. Environment and Climate Change Canada (ECCC) has developed a newland surface parameterization, named the Soil, Vegetation, and Snow (SVS) scheme. The SVS landsurface scheme features sophisticated parameterizations of hydrological processes, including watertransport through the soil. It has been shown to provide more accurate simulations of the temporaland spatial distribution of soil moisture compared to the current operational land surface scheme.Simulation of high resolution soil moisture at the field scale remains a challenge. In this study, wesimulate soil moisture maps at a spatial resolution of 100 m using the SVS land surface scheme overan experimental site located in Manitoba, Canada. Hourly high resolution soil moisture maps wereproduced between May and November 2015. Simulated soil moisture values were compared withestimated soil moisture values using a hybrid retrieval algorithm developed at Agriculture andAgri-Food Canada (AAFC) for soil moisture estimation using RADARSAT-2 Synthetic ApertureRadar (SAR) imagery. Statistical analysis of the results showed an overall promising performanceof the SVS land surface scheme in simulating soil moisture values at high resolution scale.Investigation of the SVS output was conducted both independently of the soil texture, and as afunction of the soil texture. The SVS model tends to perform slightly better over coarser texturedsoils (sandy loam, fine sand) than finer textured soils (clays). Correlation values of the simulatedSVS soil moisture and the retrieved SAR soil moisture lie between 0.753–0.860 over sand and 0.676-0.865 over clay, with goodness of fit values between 0.567–0.739 and 0.457–0.748, respectively. TheRoot Mean Square Difference (RMSD) values range between 0.058–0.062 over sand and 0.055–0.113over clay, with a maximum absolute bias of 0.049 and 0.094 over sand and clay, respectively. Theunbiased RMSD values lie between 0.038–0.057 over sand and 0.039–0.064 over clay. Furthermore,results show an Index of Agreement (IA) between the simulated and the derived soil moisturealways higher than 0.90.

The purpose of this paper is to present an outlier detection mechanism for hierarchical key management which utilizes hybrid (public and private) key management scheme for implementing lightweight cryptographic primitives in hierarchical MANETs. Further, a comparative analysis of key management schemes is to be performed for identifying an efficient key management scheme for hierarchical MANETs. In key management methods, public and private group key management schemes are integrated at local level (subgroup) and global level (network). These key management schemes uses various topologies for minimizing communicational and computational costs. After implementing an efficient key management scheme, outliers in network are identified using packet analysis at key generation, key distribution, message transmission and key re-generation phases. It is observed that Teo and Tan key management approach with shamir’s threshold key distribution mechanism is an efficient approach key management scheme for group authentication and hierarchical key management. Further, a minimum improvement of 9.7% and 0.91%, and maximum improvements of 25.3% and 87.7% are observed for Packet Delivery Rate (APDR) and Average Throughput (AT) respectively in a network of 1000 nodes. The proposed method requires four sequential analysis of outlier detection schemes at different layers of MANET protocol stack because single scheme per layer is not efficient in identifying outliers in proposed network. The proposed key management method is useful for MANETs in group authentication and implementation of lightweight cryptographic primitives with secure key. Further, outlier detection mechanism can be extended for identifying various active and passive attacks.

The rapid advancement of pervasive computing, IoT and wearable systems, given rise to low-power internet-based systems in elimination of distance complications by application of Wireless Sensor Networks, which consists of sensor, server and Cloud servers to sense various environmental readings and monitor the condition based on the data. Due to the association of vital data, and transferring it over an insecure and public communication channel, there is a critical prerequisite for sensor authentication, data integrity and data privacy. In this context many researchers had proposed various schemes for user authentication and secure data transmission over Cloud server. In this paper we proposed a three-factor user authentication and key agreement protocol for cloud server and claimed that the proposed protocol is efficient, secure and lightweight. The experimental analysis shows that the proposed scheme is resistance to well-known cryptographic attacks. Though the proposed scheme resists major cryptographic attacks, after in-depth analysis, we demonstrate that the scheme overcome many security pitfalls such as failure to resist replay attack, known session-specific temporary information attack, and failure to resist stolen-verifier attack.

This study presents a fully automated Cartesian-grid-based compressible flow solver, named FrontFlow/Violet Hierarchical Cartesian for Aeronautics based on Compressible-flow Equations (FFVHC-ACE), for large-eddy simulation (LES) and its aeronautical applications. FFVHC-ACE enables high-fidelity LES of high-Reynolds-number flows around complex geometries by adopting three key numerical methods: hierarchical Cartesian grids, wall modeling in LES, and the kinetic-energy and entropy preserving (KEEP) scheme. The hierarchical Cartesian grids allow fully automated grid generation for complex geometries in FFVHC-ACE, and high-fidelity LES of high-Reynolds-number flows around complex geometries is realized by the wall modeling and the KEEP scheme on the non-body-fitted hierarchical Cartesian grids. We apply FFVHC-ACE to wall-modeled LES around high-lift aircraft configurations at wind-tunnel-scale Reynolds number [Formula: see text] and real-flight Reynolds number [Formula: see text], demonstrating the capability of FFVHC-ACE for fully automated grid generation and high-fidelity simulations around complex aircraft configurations. The computed flowfield and aerodynamic forces at the wind-tunnel-scale Reynolds number agree well with the experimental data provided in the past AIAA High Lift Prediction Workshop (Rumsey et al., Journal of Aircraft, Vol. 56, No. 2, 2019, pp. 621–644). Furthermore, the wall-modeled LES at the real-flight Reynolds number shows good agreement of the lift coefficient with flight-test data.

Discharge- and laser-produced plasma (DLPP) devices are being used as light sources for extreme ultraviolet (EUV) generation. A key challenge for both, DPP and LPP, is achieving sufficient brightness to support the throughput requirements of nanometrology tools. To simulate the environment of a hybrid DLPP device and optimize the EUV output, we have developed an integrated HEIGHTS-DLPP computer simulation package. The package integrates simulation of two evolving plasmas (DPP and LPP) and includes modeling of a set of integrated self-consistent processes: external power source and plasma energy balance, plasma resistive magnetohydrodynamics, plasma heat conduction, detailed radiation transport (RT), and laser absorption and refraction. We simulated and optimized DLPP devices using Xe gas as a target material. We synchronized the external circuit parameters, chamber gas parameters, and laser beam temporal and spatial profiles to achieve maximum EUV output. The full 3D Monte Carlo scheme was integrated for detailed RT and EUV output calculations in Xe using more than 3600 spectral groups. The modeling results are in good agreement with Julich Forschungszentrum experimental data. Theoretical models, developed and integrated into the HEIGHTS package, showed wide capabilities and flexibility. The models and package can be used for optimization of the experimental parameters and settings, investigation of DLPP devices with complex design, analyzing the impact of integrated spatial effects and working timeline arrangement on the final EUV output, and EUV source size, shape, and angular distribution.

Abstract Background Conceptualizations of personality disorders (PD) are increasingly moving towards dimensional approaches. The definition and assessment of borderline personality disorder (BPD) in regard to changes in nosology are of great importance to theory and practice as well as consumers. We studied empirical connections between the traditional DSM-5 diagnostic criteria for BPD and Criteria A and B of the Alternative Model for Personality Disorders (AMPD). Method Raters of varied professional backgrounds possessing substantial knowledge of PDs (N = 20) characterized BPD criteria with the four domains of the Level of Personality Functioning Scale (LPFS) and 25 pathological personality trait facets. Mean AMPD values of each BPD criterion were used to support a nosological cross-walk of the individual BPD criteria and study various combinations of BPD criteria in their AMPD translation. The grand mean AMPD profile generated from the experts was compared to published BPD prototypes that used AMPD trait ratings and the DSM-5-III hybrid categorical-dimensional algorithm for BPD. Divergent comparisons with DSM-5-III algorithms for other PDs and other published PD prototypes were also examined. Results Inter-rater reliability analyses showed generally robust agreement. The AMPD profile for BPD criteria rated by individual BPD criteria was not isomorphic with whole-person ratings of BPD, although they were highly correlated. Various AMPD profiles for BPD were generated from theoretically relevant but differing configurations of BPD criteria. These AMPD profiles were highly correlated and showed meaningful divergence from non-BPD DSM-5-III algorithms and other PD prototypes. Conclusions Results show that traditional DSM BPD diagnosis reflects a common core of PD severity, largely composed of LPFS and the pathological traits of anxiousness, depressively, emotional lability, and impulsivity. Results confirm the traditional DSM criterion-based BPD diagnosis can be reliably cross-walked with the full AMPD scheme, and both approaches share substantial construct overlap. This relative equivalence suggests the vast clinical and research literatures associated with BPD may be brought forward with DSM-5-III diagnosis of BPD.

This article develops a methodological approach to assess the level of resource potential of railway enterprises, which is based on the use of hierarchy analysis to determine the share of each component of resource potential and verbal-Harrington scale to unambiguously interpret the valuesof the integrated indicator. The technique consists of seven stages, the sequence of which is presented in the diagram. One of the key stages is the development of a system of partial indicators to assess the level of development of the resource potential of the enterprise. The scientific work uses such mathematical methods as: rationing of indicators, determining the share of partial indicators to assess the level of development of resource potential by the method of T. Saati, calculating the level of agreement of experts and others. The calculation of the integrated indicator is based on the calculation of four main components of resource potential: material, labor, financial and information. The three-level hierarchical scheme of the problem of the method of analysis of hierarchies is presented, which includes the general goal – development of the railway transport enterprise, criteria – the purposes of development of resource potential of the railway transport enterprise (safety, quality of service, environmental friendliness, cost reduction and infrastructure development) and alternatives – types of enterprise resources (material, labor, financial, information). The presented methodological approach is a sensitive mathematical apparatus for assessing the level of resource potential development, with which the management of railway transport enterprises can obtain more objective information about the state of resource potential development and make effective management decisions, primarily on enterprise resource planning. The article presents the results of calculations of the level of development of resource potential (including individual components) for real operating enterprises of the railway industry according to the proposed author's method for three years and their interpretation on a verbal-numerical scale of Harrington.

What is the countercultural potential of citizen science? As a participant in the wider citizen science movement, I can attest that contemporary citizen science initiatives rarely characterise themselves as countercultural. Rather, the goal of most citizen science projects is to be seen as producing orthodox scientific knowledge: the ethos is respectability rather than rebellion (NERC). I will suggest instead that there are resonances with the counterculture that emerged in the 1960s, most visibly through an emphasis on participatory experimentation and the principles of environmental sustainability and social justice. This will be illustrated by example, through two citizen science projects that have a commitment to combining social values with scientific practice. I will then describe the explicitly countercultural organisation, Science for the People, which arose from within the scientific community itself, out of opposition to the Vietnam War. Methodological and conceptual weaknesses in the authoritative model of science are explored, suggesting that there is an opportunity for citizen science to become anti-hegemonic by challenging the hegemony of science itself. This reformulation will be expressed through Deleuze and Guattari's notion of nomadic science, the means through which citizen science could become countercultural. Counterculture Before examining the countercultural potential of citizen science, I set out some of the grounds for identifying a counterculture drawing on the ideas of Theodore Roszak, who invented the term counterculture to describe the new forms of youth movements that emerged in the 1960s (Roszak). This was a perspective that allowed the carnivalesque procession of beatniks, hippies and the New Left to be seen as a single paradigm shift combining psychic and social revolution. But just as striking and more often forgotten is the way Roszak characterised the role of the counterculture as mobilising a vital critique of the scientific worldview (Roszak 273-274). The concept of counterculture has been taken up in diverse ways since its original formation. We can draw, for example, on Lawrence Grossberg's more contemporary analysis of counterculture (Grossberg) to clarify the main concepts and contrast them with a scientific approach. Firstly, a counterculture works on and through cultural formations. This positions it as something the scientific community would see as the other, as the opposite to the objective, repeatable and quantitative truth-seeking of science. Secondly, a counterculture is a diverse and hybrid space without a unitary identity. Again, scientists would often see science as a singular activity applied in modulated forms depending on the context, although in practice the different sciences can experience each other as different tribes. Thirdly, a counterculture is lived as a transformative experience where the participant is fundamentally changed at a psychic level through participation in unique events. Contrast this with the scientific idea of the separation of observer and observed, and the objective repeatability of the experiment irrespective of the experimenter. Fourthly, a counterculture is associated with a unique moment in time, a point of shift from the old to the new. For the counterculture of the 1960s this was the Age of Aquarius. In general, the aim of science and scientists is to contribute to a form of truth that is essentially timeless, in that a physical law is assumed to hold across all time (and space), although science also has moments of radical change with regard to scientific paradigms. Finally, and significantly for the conclusions of this paper, according to Roszak a counterculture stands against the mainstream. It offers a challenge not at the level of detail but, to the fundamental assumptions of the status quo. This is what “science” cannot do, in as much as science itself has become the mainstream. It was the character of science as the bedrock of all values that Roszak himself opposed and for which he named and welcomed the counterculture. Although critical of some of the more shallow aspects of its psychedelic experimentation or political militancy, he shared its criticism of the technocratic society (the technocracy) and the egocentric mode of consciousness. His hope was that the counterculture could help restore a visionary imagination along with a more human sense of community. What Is Citizen Science? In recent years the concept of citizen science has grown massively in popularity, but is still an open and unstable term with many variants. Current moves towards institutionalisation (Citizen Science Association) are attempting to marry growth and stabilisation, with the first Annual General Meeting of the European Citizen Science Association securing a tentative agreement on the common principles of citizen science (Haklay, "European"). Key papers and presentations in the mainstream of the movement emphasise that citizen science is not a new activity (Bonney et al.) with much being made of the fact that the National Audubon Society started its annual Christmas Bird Count in 1900 (National Audubon Society). However, this elides the key role of the Internet in the current surge, which takes two distinct forms; the organisation of distributed fieldwork, and the online crowdsourcing of data analysis. To scientists, the appeal of citizen science fieldwork follows from its distributed character; they can research patterns over large scales and across latitudes in ways that would be impossible for a researcher at a single study site (Toomey). Gathering together the volunteer, observations are made possible by an infrastructure of web tools. The role of the citizen in this is to be a careful observer; the eyes and ears of the scientist in cyberspace. In online crowdsourcing, the internet is used to present pattern recognition tasks; enrolling users in searching images for signs of new planets or the jets of material from black holes. The growth of science crowdsourcing is exponential; one of the largest sites facilitating this kind of citizen science now has well in excess of a million registered users (Zooniverse). Such is the force of the technological aura around crowdsourced science that mainstream publications often conflate it with the whole of citizen science (Parr). There are projects within citizen science which share core values with the counterculture as originally defined by Roszak, in particular open participation and social justice. These projects also show characteristics from Grossberg's analysis of counterculture; they are diverse and hybrid spaces, carry a sense of moving from an old era to a new one, and have cultural forms of their own. They open up the full range of the scientific method to participation, including problem definition, research design, analysis and action. Citizen science projects that aim for participation in all these areas include the Extreme Citizen Science research group (ExCiteS) at University College London (UCL), the associated social enterprise Mapping for Change (Mapping for Change), and the Public Laboratory for Open Technology and Science (Public Lab). ExCiteS sees its version of citizen science as "a situated, bottom-up practice" that "takes into account local needs, practices and culture". Public Lab, meanwhile, argue that many citizen science projects only offer non-scientists token forms of participation in scientific inquiry that rarely amount to more that data collection and record keeping. They counter this through an open process which tries to involve communities all the way from framing the research questions, to prototyping tools, to collating and interpreting the measurements. ExCiteS and Public Lab also share an implicit commitment to social justice through scientific activity. The Public Lab mission is to "put scientific inquiry at the heart of civic life" and the UCL research group strive for "new devices and knowledge creation processes that can transform the world". All of their work is framed by environmental sustainability and care for the planet, whether it's enabling environmental monitoring by indigenous communities in the Congo (ExCiteS) or developing do-it-yourself spectrometry kits to detect crude oil pollution (Public Lab, "Homebrew"). Having provided a case for elements of countercultural DNA being present in bottom-up and problem-driven citizen science, we can contrast this with Science for the People, a scientific movement that was born out of the counterculture. Countercultural Science from the 1970s: Science for the People Science for the People (SftP) was a scientific movement seeded by a rebellion of young physicists against the role of US science in the Vietnam War. Young members of the American Physical Society (APS) lobbied for it to take a position against the war but were heavily criticised by other members, whose written complaints in the communications of the APS focused on the importance of scientific neutrality and the need to maintain the association's purely scientific nature rather than allowing science to become contaminated by politics (Sarah Bridger, in Plenary 2, 0:46 to 1:04). The counter-narrative from the dissidents argued that science is not neutral, invoking the example of Nazi science as a justification for taking a stand. After losing the internal vote the young radicals left to form Scientists and Engineers for Social and Political Action (SESPA), which later became Science for the People (SftP). As well as opposition to the Vietnam War, SftP embodied from the start other key themes of the counterculture, such as civil rights and feminism. For example, the first edition of Science for the People magazine (appearing as Vol. 2, No. 2 of the SESPA Newsletter) included an article about leading Black Panther, Bobby Seale, alongside a piece entitled “Women Demand Equality in Science.” The final articles in the same issue are indicators of SftP's dual approach to science and change; both the radicalisation of professionals (“Computer Professionals for Peace”) and the demystification of technical practices (“Statistics for the People”) (Science for the People). Science for the People was by no means just a magazine. For example, their technical assistance programme provided practical support to street health clinics run by the Black Panthers, and brought SftP under FBI surveillance (Herb Fox, in Plenary 1, 0:25 to 0:35). Both as a magazine and as a movement, SftP showed a tenacious longevity, with the publication being produced every two months between August 1970 and May/June 1989. It mutated through a network of affiliated local groups and international links, and was deeply involved in constructing early critiques of nuclear power and genetic determinism. SftP itself seems to have had a consistent commitment to non-hierarchical processes and, as one of the founders expressed it, a “shit kicking” approach to putting its principles in to practice (Al Weinrub, in Plenary 1, 0:25 to 0:35). SftP criticised power, front and centre. It is this opposition to hegemony that puts the “counter” into counterculture, and is missing from citizen science as currently practised. Cracks in the authority of orthodox science, which can be traced to both methodologies and basic concepts, follow in this paper. These can be seen as an opportunity for citizen science to directly challenge orthodox science and thus establish an anti-hegemonic stance of its own. Weaknesses of Scientific Hegemony In this section I argue that the weaknesses of scientific hegemony are in proportion to its claims to authority (Feyerabend). Through my scientific training as an experimental particle physicist I have participated in many discussions about the ontological and epistemological grounds for scientific authority. While most scientists choose to present their practice publicly as an infallible machine for the production of truths, the opinions behind the curtain are far more mixed. Physicist Lee Somolin has written a devastating critique of science-in-practice that focuses on the capture of the institutional economy of science by an ideological grouping of string theorists (Smolin), and his account is replete with questions about science itself and ethnographic details that bring to life the messy behind-the-scenes conflicts in scientific-knowledge making. Knowledge of this messiness has prompted some citizen science advocates to take science to task, for example for demanding higher standards in data consistency from citizen science than is often the case in orthodox science (Haklay, "Assertions"; Freitag, "Good Science"). Scientists will also and invariably refer to reproducibility as the basis for the authority of scientific truths. The principle that the same experiments always get the same results, irrespective of who is doing the experiment, and as long as they follow the same method, is a foundation of scientific objectivity. However, a 2012 study of landmark results in cancer science was able to reproduce only 11 per cent of the original findings (Begley and Ellis). While this may be an outlier case, there are broader issues with statistics and falsification, a bias on positive results, weaknesses in peer review and the “publish or perish” academic culture (The Economist). While the pressures are all-too-human, the resulting distortions are rarely acknowledged in public by scientists themselves. On the other hand, citizen science has been slow to pick up the gauntlet. For example, while some scientists involved in citizen science have commented on the inequality and inappropriateness of orthodox peer review for citizen science papers (Freitag, “What Is the Role”) there has been no direct challenge to any significant part of the scientific edifice. I argue that the nearest thing to a real challenge to orthodox science is the proposal for a post-normal science, which pre-dates the current wave of citizen science. Post-normal science tries to accommodate the philosophical implications of post-structuralism and at the same time position science to tackle problems such as climate change, intractable to reproducibility (Funtowicz and Ravetz). It accomplishes this by extending the domains in which science can provide meaningful answers to include issues such as global warming, which involve high decision stakes and high uncertainty. It extends traditional peer review into an extended peer community, which includes all the stakeholders in an issue, and may involve active research as well as quality assessment. The idea of extended peer review has obvious overlaps with community-oriented citizen science, but has yet to be widely mobilised as a theoretical buttress for citizen-led science. Prior even to post-normal science are the potential cracks in the core philosophy of science. In her book Cosmopolitics, Isabelle Stengers characterises the essential nature of scientific truth as the ability to disqualify and exclude other truth claims. This, she asserts, is the hegemony of physics and its singular claim to decide what is real and what is true. Stengers traces this, in part, to the confrontation more than one hundred years ago between Max Planck and Ernst Mach, whereas the latter argued that claims to an absolute truth should be replaced by formulations that tied physical laws to the human practices that produced them. Planck stood firmly for knowledge forms that were unbounded by time, space or specific social-material procedures (Stengers). Although contemporary understandings of science are based on Planck's version, citizen science has the potential to re-open these questions in a productive manner for its own practices, if it can re-conceive of itself as what Deleuze and Guattari would call nomadic science (Deleuze; Deleuze & Guattari). Citizen Science as Nomadic Science Deleuze and Guattari referred to orthodox science as Royal Science or Striated Science, referring in part to its state-like form of authority and practice, as well as its psycho-social character. Their alternative is a smooth or nomadic science that, importantly for citizen science, does not have the ambition to totalise knowledge. Nomadic science is a form of empirical investigation that has no need to be hooked up to a grand narrative. The concept of nomadic science is a natural fit for bottom-up citizen science because it can valorise truths that are non-dual and that go beyond objectivity to include the experiential. In this sense it is like the extended peer review of post-normal science but without the need to be limited to high-risk high-stakes questions. As there is no a priori problem with provisional knowledges, it naturally inclines towards the local, the situated and the culturally reflective. The apparent unreliability of citizen science in terms of participants and tools, which is solely a source of anxiety, can become heuristic for nomadic science when re-cast through the forgotten alternatives like Mach's formulation; that truths are never separated from the specifics of the context and process that produced them (Stengers 6-18; 223). Nomadic science, I believe, will start to emerge through projects that are prepared to tackle toxic epistemology as much as toxic pollutants. For example, the Community Based Auditing (CBA) developed by environmental activists in Tasmania (Tattersall) challenges local alliances of state and extractive industries by undermining their own truth claims with regards to environmental impact, a process described in the CBA Toolbox as disconfirmation. In CBA, this mixture of post-normal science and Stenger's critique is combined with forms of data collection and analysis known as Community Based Sampling (Tattersall et al.), which would be recognisable to any citizen science project. The change from citizen science to nomadic science is not a total rupture but a shift in the starting point: it is based on an overt critique of power. One way to bring this about is being tested in the “Kosovo Science for Change” project (Science for Change Kosovo), where I am a researcher and where we have adopted the critical pedagogy of Paulo Freire as the starting point for our empirical investigations (Freire). Critical pedagogy is learning as the co-operative activity of understanding—how our lived experience is constructed by power, and how to make a difference in the world. Taking a position such as nomadic science, openly critical of Royal Science, is the anti-hegemonic stance that could qualify citizen science as properly countercultural. Citizen Science and Counterculture Counterculture, as I have expressed it, stands against or rejects the hegemonic culture. However, there is a strong tendency in contemporary social movements to take a stance not only against the dominant structures but against hegemony itself. They contest what Richard Day calls the hegemony of hegemony (Day). I witnessed this during the counter-G8 mobilisation of 2001. Having been an activist in the 1980s and 1990s I was wearily familiar with the sectarian competitiveness of various radical narratives, each seeking to establish itself as the correct path. So it was a strongly affective experience to stand in the convergence centre and listen to so many divergent social groups and movements agree to support each other's tactics, expressing a solidarity based on a non-judgemental pluralism. Since then we have seen the emergence of similarly anti-hegemonic countercultures around the Occupy and Anonymous movements. It is in this context of counterculture that I will try to summarise and evaluate the countercultural potential of citizen science and what being countercultural might offer to citizen science itself. To be countercultural it is not enough for citizen science to counterpose participation against the institutional and hierarchical aspects of professional science. As an activity defined purely by engagement it offers to plug the legitimacy gap for science while still being wholly dependent on it. A countercultural citizen science must pose a strong challenge to the status quo, and I have suggested that a route to this would be to develop as nomadic science. This does not mean replacing or overthrowing science but constructing an other to science with its own claim to empirical methods. It is fair to ask what this would offer citizen science that it does not already have. At an abstract level it would gain a freedom of movement; an ability to occupy Deleuzian smooth spaces rather than be constrained by the striation of established science. The founders of Science for the People are clear that it could never have existed if it had not been able to draw on the mass movements of its time. Being countercultural would give citizen science an affinity with the bottom-up, local and community-based issues where empirical methods are likely to have the most social impact. One of many examples is the movement against fracking (the hydraulic fracturing of deep rock formations to release shale gas). Together, these benefits of being countercultural open up the possibility for forms of citizen science to spread rhizomatically in a way that is not about immaterial virtual labour but is itself part of a wider cultural change. 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