Tunnel Surrounding Rock Displacement Prediction Using Support Vector Machine Multi-step-ahead prediction of tunnel surrounding rock displacement is an effective way to ensure the safe and economical construction of tunnels. This paper presents a multi-step-ahead prediction model, which is based on support vector machine (SVM), for tunnel surrounding rock displacement prediction. To improve the training efficiency of SVM, shuffled complex evolution algorithm (SCE-UA) is also performed through some exponential transformation. The data from the Chijiangchong tunnel are used to examine the performance of the prediction model. Results show that SVM is generally better than artificial neural network (ANN). This indicates that SVM is a feasible and effective multi-step method for tunnel surrounding rock displacement prediction. Many problems, such as tunnel surrounding rock deformation and tunnel lining crack, may lead to the instability of the tunnel during tunnel construction. It is important to obtain reliable estimates of potential tunneling problems as early as possible. Statistical Process Control is an essential element for quality assurance 1 . The displacement statistics and analysis of the tunnel surrounding rock is the most common way to estimate the conditions of the tunnel. The lack of effective displacement prediction may result in increased cost and delays. Moreover, based on the displacement of tunnel surrounding rock, project managers identify the tunnel conditions and effectively operate their constructed facilities, for example, the appropriateness of support quantity and type can be determined. Furthermore, some potential danger occasions can be avoided by necessary emergency measures in advance. There are many literatures devoted to the displacement prediction of tunnel surrounding rock [2] [3] .. For many engineering application, it is required that time series values be predicted many time-steps into the future. Many researches have applied multi-step-ahead (MS) techniques to deal with their problems. Cheng et al. 4 proposed a multi-step-ahead prediction model to predict a long-term discharge in the hydropower system. In the model, dynamic spline interpolation with multilayer adaptive time-delay neural network had improved the prediction accuracy. Parlos et al. 5 presented multi-step-ahead predictions for highly complex systems, and then they attempted to improve the prediction accuracy with dynamic recurrent neural networks. Lee and Billings 6 presented multi-step ahead predictions for solving the non-linear time series examples. Chevillon and Hendry 7 used non-parametric direct multi-step-ahead to predict economic processes, particularly for a non-stationary data generating process. Other researches for multi-step-ahead can be found in the studies by Liu et al. 8 and Yu et al. 9 It is also essential to provide a dependable displacement of tunnel surrounding rock for planning, and management activities during tunnel construction. However, there are some changes in the ground conditions during tunnel construction, and thus it is very difficult to predict the displacement of tunnel surrounding rock accurately. Support vector machines (SVM) is a relatively new kind of learning machine which has been applied successfully in solving various time series forecasting problems. [10] [11] Other literatures on SVM can also be found in the studies by Xu et al. 12 and Reyaz-Ahmed et al. 13 Their numerical results indicate that SVM shows much resistance to the overfitting problem and can provide a high generalization performance.. These successful applications suggest that SVM is an acceptable tool to provide accurate displacement prediction of tunnel surrounding rock. However, the performance of SVM highly relies on the parameters and there is a need to determine the values of parameters. Many literatures have proved that the proper choice of the parameters in SVM will greatly affect its performance. Improper parameter values could result in the overfitting or underfitting of the training data points. 14 To optimize the parameters in SVM, grid-search [15] [16] is the most reliable method which tries values of each parameter across the specified search range using geometric steps. However, grid searcher requires too many evaluations at many points within the grid for each parameter. Quick and effective tools have been paid more attentions to improving the efficiency of the parameter optimization in SVM. Lorena et al. 17 proposed genetic algorithms to select the proper parameter values for SVM. Ohn et al. 18 presented a new kernel function to determine appropriate parameters in SVM. Hou and Li 19 identified the parameters in SVM by using evolution strategy with covariance matrix adaptation. Lin et al. 20 presented SVM for hydrological prediction and a shuffled complex evolution algorithm (SCE-UA) was used to identify appropriate parameters in SVM. Thus, this paper applies SCE-UA to find the appropriate parameters for SVM. This paper is organized as follows. In Section 2, we describe the MS prediction problem on the displacement of tunnel surrounding. In Section 3 we introduce the SVM model for regression, and parameters optimization with SCE-UA. In Section 4, some computational results are discussed and lastly, the conclusions are provided in section 5. Proving accurate displacement prediction in advance is one of the key aspects for identifying the potential danger occasions and reducing losses as possible during tunnel construction. If the long-time displacement prediction can be provided, there will be enough time for project managers to carry out some effective measures. Thus, the objective of this study is to develop a MS prediction model (SVM) for displacement prediction of surrounding rock. To improve the training efficiency of SVM, a SCE-UA algorithm is implemented for optimizing the parameters in SVM. Consider the fact that long-time prediction by MS technique will worsen the prediction errors. To determine the number of prediction steps, an experiment from the Chijiangchong tunnel is applied and the number of prediction steps is determined as 7 in this study. Then, the performance of the proposed method is also evaluated by the data. Results show that the proposed SVM model can provide better performance in most situations than ANN. Thus, SVM can be a potential tool for tunnel surrounding rock displacement prediction. To further analyze the characteristic of the MS prediction for the tunnel surrounding rock, we select the 6 th to the 12 th of the data from the second section as test bed I (note: the first five data as the inputs), and the 27 th to 33 rd of the data from the second section as test bed II. Here, the two test beds reflect respectively two typical cases, one is the phase that tunnel surrounding displacement increases obviously, and the other is the phase that tunnel surrounding displacement changes smoothly.. Then to evaluate the performance of the proposed model, a standard artificial neural network (ANN) model with three-layer is also introduced in this paper. To get a good comparison, the same input and output variables of ANN should be the same to the SVM. Then a scaled conjugate gradient algorithm 31 is employed for training. To prevent overtraining and improve the generalization ability, the hidden neurons are generally optimized by a trial and error procedure. In this study, the final ANN architecture consists of five hidden neurons that yield the best performance. Then, we compare the performance of the SVM with that of ANN by using RMSE. Fig. 7 depicts the prediction performance of the two models on the two test beds. It can be found that two models obtain more accurate values at the former data than the latter data in each test bed. It is can be attributed to the fact MS predictor is based on the recursive use of SS predictor for reaching the end-point in the horizon. The prediction errors at the beginning of the horizon accumulate and propagate till to the end prediction. It is true that the prediction errors increase, however, in some real-world applications, especially for the displacement prediction of tunnel surrounding rock which has a relatively smaller period, moreover, it requires enough time for taking measures to combat the danger occasions. Thus it is acceptable to adapt to MS techniques to predict the future displacements. The relationship between observations and predictions for the two test beds can be also illustrated in Fig. 8 . It is obvious that the errors from SVM models generally are smaller than that of ANN. This can be explained that SVM uses the structural risk minimization principle to minimize the generalization error, while ANN uses the empirical risk minimization principle to minimize the training error. Furthermore, SVM always seeks to find the global solution while ANN may tend to fall into a local optimal solution. Therefore, it is feasible to solve the displacement prediction of tunnel surrounding rock with our model.

B B I I B O O O O O B O B B I I O O O O O O O O O O O O O O O O O O B O O O O O O O O B O B B I I B O O O O O O B O O O O B O O O O O O O O O O O O B O O O O O O O O B O O O O B O O O O O O O O O O O B O O O O O O O O B B I I B O O O O B O O O O B O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O B O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O B O O O O O O O O O O O O O B O O B O O O O O O B O O O O O O O B O O O O B O O O O O O B O O O O O O O O O O O O O B O O O O O B O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O B O O O O O O O O O B O B O O O O O O O O B O O O O O B O O O O O O B O O O O O O B O O O O O O B O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O B B I I B O O O O O O O O B O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O B O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O B O O O O O


A call for an international network of genomic observatories (GOs) We are entering a new era in genomics-that of large-scale, place-based, highly contextualized genomic research. Here we review this emerging paradigm shift and suggest that sites of utmost scientific importance be expanded into 'Genomic Observatories' (GOs). Investment in GOs should focus on the digital characterization of whole ecosystems, from all-taxa biotic inventories to time-series 'omics studies. The foundational layer of biodiversity-genetic variation-would thus be mainstreamed into Earth Observation systems enabling predictive modelling of biodiversity dynamics and resultant impacts on ecosystem services. In summary, the establishment of GOs at a subset of existing sites of major scientific importance will pave the way for taking the "biological pulse" of the planet. Thanks to DNA's remarkable uniformity and ubiquity, well-contextualized genetic data (like temperature and other meteorological measurements) are readily re-used across disciplines, institutions, and geographies. A network of GOs, equipped to generate and share DNA-level observations according to global data standards, would provide a powerful research infrastructure with which to address questions at the local level, cutting across habitat types and taxa, while also informing regional and global models. Long-term, DNA-centric, place-based work will go far beyond the sequencing of independent (unrelated, allopatric) genomes, to understanding the complete set of interactions of living organisms in a particular environment (ecosystem). Such an initiative must have a long-term (>30 year) vision. It should be built in collaboration with, and embedded within, existing networks like the International Long Term Ecological Research Network [38] and related initiatives (e.g., NEON [39], SI GEO [40], GEO BON [41], etc.). It will thus offer the promise of 'accelerating returns' by increasing our potential to characterize interaction networks and to address higher levels of organization. Such an approach would render tangible benefits to society through the enhanced ecosystem services expected from a better understanding of biodiversity dynamics. More information can be found at http://genomicobservatories.org.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B I O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O


The Australian general public's perceptions of having a personally controlled electronic health record (PCEHR) Objective: The move internationally by Governments and other health providers to encourage patients to have their own electronic personal health record (e-PHRs) is growing exponentially. In Australia the initiative for a personally controlled electronic health record (known as PCEHR) is directed towards the public at large. The first objective of this study then, is to examine how individuals in the general population perceive the promoted idea of having a PCEHR. The second objective is to extend research on applying a theoretically derived consumer technology acceptance model to guide the research. Method: An online survey was conducted to capture the perceptions and beliefs about having a PCEHR identified from technology acceptance models and extant literature. The survey was completed by 750 Queensland respondents, 97% of whom did not have a PCEHR at that time. The model was examined using exploratory factor analysis, regressions and mediation tests. Results: Findings support eight of the 11 hypothesised relationships in the model. Perceived value and perceived risk were the two most important variables explaining attitude, with perceived usefulness and compatibility being weak but significant. The perception of risk was reduced through partial mediation from trust and privacy concerns. Additionally, web-self efficacy and ease of use partially mediate the relationship between attitude and intentions. Conclusions: The findings represent a snapshot of the early stages of implementing this Australian initiative and captures the perceptions of Queenslanders who at present do not have a PCEHR. Findings show that while individuals appreciate the value of having this record, they do not appear to regard it as particularly useful at present, nor is it particularly compatible with their current engagement with e-services. Moreover, they will need to have any concerns about the risks alleviated, particularly through an increased sense of trust and reduction of privacy concerns. It is noted that although the respondents are non-adopters, they do not feel that they lack the necessary web skills to set up and use a PCEHR. To the best of our knowledge this is one of a very limited number of studies that examines a national level implementation of an e-PHR system, where take-up of the PCEHR is optional rather than a centralised, mandated requirement. Objective: The move internationally by Governments and other health providers to encourage patients to have their own electronic personal health record (e-PHRs) is growing exponentially. In Australia the initiative for a personally controlled electronic health record (known as PCEHR) is directed towards the public at large. The first objective of this study then, is to examine how individuals in the general population perceive the promoted idea of having a PCEHR. The second objective is to extend research on applying a theoretically derived consumer technology acceptance model to guide the research. Method: An online survey was conducted to capture the perceptions and beliefs about having a PCEHR identified from technology acceptance models and extant literature. The survey was completed by 750 Queensland respondents, 97% of whom did not have a PCEHR at that time. The model was examined using exploratory factor analysis, regressions and mediation tests. Results: Findings support eight of the 11 hypothesised relationships in the model. Perceived value and perceived risk were the two most important variables explaining attitude, with perceived usefulness and compatibility being weak but significant. The perception of risk was reduced through partial mediation from trust and privacy concerns. Additionally, web-self efficacy and ease of use partially mediate the relationship between attitude and intentions. Conclusions: The findings represent a snapshot of the early stages of implementing this Australian initiative and captures the perceptions of Queenslanders who at present do not have a PCEHR. Findings show that while individuals appreciate the value of having this record, they do not appear to regard it as particularly useful at present, nor is it particularly compatible with their current engagement with e-services. Moreover, they will need to have any concerns about the risks alleviated, particularly through an increased sense of trust and reduction of privacy concerns. It is noted that although the respondents are non-adopters, they do not feel that they lack the necessary web skills to set up and use a PCEHR. To the best of our knowledge this is one of a very limited number of studies that examines a national level implementation of an e-PHR system, where take-up of the PCEHR is optional rather than a centralised, mandated requirement.3 The international interest in introducing e-PHRs has emerged as an important area of research in the medical and health informatics domain [1, 2] . This interest has been summarised in scoping studies, such as [3] [4] [5] . Much of the research, however, focuses on 'tethered' e-PHRs [4] meaning records that are offered by a health provider or a specific organisation, such as an employer. 'Untethered' e-PHRs refers to health records that can be installed on a personal computer or Website for personal use and are considered to be standalone records [4] . The conceptual model depicted in Figure 1 is tested using a single quantitative study.. We used an online survey research design as we felt it was important that respondents were familiar with using the Internet to be able to provide reliable information about having a PCEHR as it represents an e-service.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B


Secure quantum carriers for quantum state sharing We develop the concept of quantum carrier and show that messages can be uploaded and downloaded from this carrier and while in transit, these messages are hidden from external agents. We explain in detail the working of the quantum carrier for different communication tasks, including quantum key distribution, classical secret and quantum state sharing among a set of n players according to general threshold schemes. The security of the protocol is discussed and it is shown that only the legitimate subsets can retrieve the secret messages, the collaboration of all the parties is needed for the continuous running of the protocol and maintaining the carrier. Entanglement has been used in many different protocols of quantum information theory, from teleportation and key distribution to secret sharing [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] . In all these protocols, entanglement is a resource which is completely consumed by measurements of the parties involved and should be generated anew for next rounds of protocol. It is true that generating and maintaining entanglement between several particles is very difficult. Yet with the developments in realizing quantum repeaters [11, 12, 13] , creating and maintaining long distance entanglement between stationary quantum systems becomes more feasible in the (possibly distant) future. It is thus rewarding to imagine if this entanglement can used in a different way, that is as a carrier of information, which modulates and transmits quantum information, in the same way as carrier waves in classical communication systems carry modulated messages. In this new application, we can imagine that arbitrary quantum states are uploaded (entangled) to the carrier by the sender and downloaded (disentangled) from the carrier by the receiver(s), in such a way that at the end of the protocol, the carrier remains intact and ready for use in next rounds. The role of the quantum carrier and its entanglement with the messages will be to hide messages from adversaries, hence the term secure quantum carrier.. This new way for using entanglement was first reported in [14] for quantum key distribution and then was developed for a simple secret sharing scheme in [8] . In this paper we want to develop it further and provide quantum carriers for secret sharing schemes for general threshold schemes [15, 16] . Needless to say, our aim is not to develop new quantum secret sharing schemes, but to develop a quantum carrier for distributing in a secure way the already known quantum secrets among the parties. Our emphasis is thus on the very concept of secure quantum carrier and the way it can be used in quantum communication protocols. In the particular context of quantum secret sharing, as we will see it allows us to generate broader threshold schemes than those of [17, 18] .. In particular we have to stress the difference with the works in [17, 18] where it was shown that graph state formalism [19] can act as a framework for unifying some of the secret sharing protocols, albeit not for general threshold structures. The idea of [17, 18] was to encode the secret in some local actions of the dealer on a vertex of a suitably chosen weighted graph state. Local measurements of the players on different vertices of this graph, could then reveal the secret to authorized subsets of players. In this way, it was shown that threshold schemes of the type (n, n), (2, 3) and (3, 5) can be implemented in a unified way for various forms of channels interconnecting the dealer and the players. Therefore the works of [17, 18] belong to the same class as in [1] , in which entanglement is fully consumed due to measurements of the players.. It is to be noted that while the idea of a fixed quantum carrier has an appeal for communication, a price should be paid for its implementation: it requires a larger number of particles to be entangled at the beginning and end of the protocol, but at the end of each round a fixed amount of entanglement remains in the form of a carrier. Nevertheless, it is worth to develop such a concept from theoretical side and hope that it will someday become close to reality.. We remark that although we present our analysis for secure communication of basis states or classical information, the idea also works for sending arbitrary quantum states. In the simplest protocol discussed in the beginning of the paper we explicitly show this, although we will not repeat it for other general schemes.. The structure of this paper is as follows. In section 2 we put forward the basic requirements that a quantum carrier should satisfy, in section 3 we explain the basic method in the simplest possible setting, that is quantum key distribution between two parties. Then in section 4 we briefly explain the use of quantum carrier for the simplest secret sharing scheme, where one dealer, wants to share a secret between two different players who have equal right for retrieving the message collaboratively. For this reason, this is called a (2, 2) secret shring scheme. This is then generalized to the (n, n) scheme where a secret is to be shared between n players and all the n players can retrieve the message collaboratively. Finally in section 6 we define the carrier for the (k, n) threshold scheme where any of the k players can retrieve the secret, although collaboration of all of the players is needed for the continuous running and security of the protocol. We end the paper with conclusion and outlook.. • While in transit, the messages should be hidden from third parties so that no intercept-resend strategy can reveal the identity of the message.. • Eve should not be able to entangle herself to the quantum carrier without being detected by the legitimate parties. This property is to prevent Eve from conducting more complex attacks.. Once such criteria are met, we say that a secure quantum carrier has been set up for this communication task. In the rest of this paper we present quantum carriers for various communication tasks. We should stress again that these requirements are purely from the theoretical point of view, the main difficulty will obviously be to maintain the carrier for a long enough time so that it can be used for passing many quantum states before the entanglement decays and becomes useless. We have developed the concept of quantum carrier [14, 8] to encompass more complex classical secret and quantum sharing schemes. We have described the procedure of uploading and downloading messages to and from the carrier in increasingly complex situations, i.e. for quantum key distributions, for (2, 2), (n, n) and (k, n) threshold schemes. As described in the text, for each task a different quantum carrier is required, although it seems that they all have similar forms (38). We have also shown that simple intercept-resend attacks can destroy the pattern of entanglement in the carrier which can be detected by legitimate parties. In the general (k, n) secret sharing scheme, although collaboration of all parties is required for the continuous running of the protocol (i.e. cleaning of the carrier from the remnants of the transmitted messages), any set of k players can download and retrieve the message.. We hope that together with the previous results, the concept of quantum carrier can attract the attention of other researchers who will develop it into more complex forms. An important question is whether there can be universal carriers between a set of players, which can be used for various cryptographic tasks on demand of the players, i.e. quantum key distribution between the sender and a particular receiver, or secret sharing between the sender and a particular set of players.? Another interesting general question is whether there exist general carriers which can be used to simultaneously send many messages to different receivers via a single quantum carrier, in the same way that frequency modulation is used for such a goal in classical communication. Finally the question of general proof of security of these types of carrier-based protocols remain to be investigated. which is zero mod p, since p − 1 is even. The recursion relations above then imply that S m (p) = 0 for all 1 ≤ m < p. The case m = p should be calculated directly, using the Euler theorem which states that for every prime number p, j p−1 = 1 mod p. The result is immediate, namely S p−1 (p) = −1. Now using the relation (74) it's easy to verify that the vectors e i in (71) satisfy the desired properties in (72).

O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O B O O O O O O O O O O O O O O B I O O O O O B O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B I O O O B I O O O O O O O O O O O O O O B I O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Central points and approximation in residuated lattices Abstract. The paper presents results on approximation in residuated lattices given that closeness is assessed by means of biresiduum. We describe central points and optimal central points of subsets of residuated lattices and provide properties of these points. In addition, we present algorithms for two problems regarding optimal approximation.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Rotation Map with a Controlling Segment: Basic Analysis and Application to A/D Converters This paper studies the rotation map with a controlling segment. As a parameter varies, the map exhibits superstable periodic orbits, chaos and rich bifurcation phenomena. The map is applicable to an A/D converter having efficient resolution characteristics. The converter can be realized as a circuit model based on a spiking neuron and the rate-coding. Presenting a test circuit, basic operation is confirmed experimentally. 1D maps can exhibit various complex periodic/non-periodic phenomena. Adding a flat-segment to the 1D maps, the complex behavior can be changed into SSPOs [1] - [7] . The SSPO has interesting properties: it is superstable for initial state, it can be very sensitive for parameter(s), and transient to the steady state is very fast. Such phenomena appear in several practical/mathematical systems: chaos control systems [2] , [3] , a model of the Belousov-Zhabontinsky reaction system [4] , piecewise constant spiking oscillators [5] , a model of dc/dc converters [6] and coupled neuron models [7] . Analysis of such 1D maps is important from both basic and practical viewpoints. Let us consider the 1D map described by. where n denotes discrete time, x n ∈ I 1 ≡ [0, 1] is a state variable, and W ≡ [x c − , x c + ] is a window with center x c and width 2 . On the window W, the map has segment through (x c , h) with slope s. The map and segment. Manuscript received December 18, 2007 . Manuscript revised February 15, 2008 . † The authors are with the EEE Dept., Hosei University, Koganei-shi, 184-8584 Japan.. a) E-mail: matsuoka@nonlinear.k.hosei.ac.jp DOI: 10.1093/ietfec/e91-a.7.1725 are referred to as Wmap and controlling segment, respectively. Figure 1 shows typical examples. If the controlling segment does not present ( = 0), the Wmap correspond to chaotic maps in Fig. 1(a) , the rotation map of the circle Fig. 1 (b) and so on [8] . The map can exhibit chaotic or quasi-periodic orbit. Adding the controlling segment with s = 0, the orbits are changed into SSPOs. Figures 1(a ) and (b ) suggest effects of small perturbation of s: stability of the chaos-based Wmap may be destroyed [6] whereas the rotation-based Wmap can remain stability. This paper studies dynamics of the rotation-based Wmap (RWmap) and its application. First, we investigate dynamics of the RWmap and SSPOs. When s = 0, the RWmap exhibits a variety of SSPOs. When s 0, the SSPO can be changed into stable periodic orbit (SPO) and chaotic orbits. If = 0 the RWmap is equivalent to the rotation map [8] hence the orbit stability is governed completely by the slope s. Second, we propose an application to ADCs that use the SPO as an encoding source. The ADC can have higher resolution and stronger robustness than basic ADCs [9] - [11] . Third, we present an implementation method of the ADC based on a spiking neuron model [12] . An analog dc input is converted into digital output through spikephase and approximation is based on the rate-encoding. As discussed in [12] - [14] , advantages of spike-based ADC include robustness for initial value and low power consumption.. For novelty and motivation of this paper, we emphasize the following. Reference [1] firstly discusses SSPOs in rotation map with flat-segment (s = 0) and this paper firstly discusses bifurcation for s 0. Reference [12] firstly presents a spike-based ADC of binary encoding and this paper firstly presents a spike-based ADC of rate-encoding. This paper triggers to develop SSPO-based bifurcation theory, to design spike-based encoders and to understand spike-based information processing where the temporal and rate encodings play a key role [15] . Preliminary results along these lines can be found in [16] and [17] . Figure 2 shows the RWmap with s = 0: We have studied the dynamics of the RWmap and its application to ADC. When a slope of the controlling segment is zero, the RWmap can have various SSPOs. Varying the slope of the controlling segment, the slope can control the behavior and the RWmap exhibits interesting bifurcation phenomena. We have presented an application of the RWmap to ADC that can realize higher resolution and stronger robustness than the SDMs. Based on spiking neuron model, we have implemented the RWmap-based ADC based on the rate-encoding. Future problems include analysis of dynamics of the spike-based ADCs, design of practical circuits and detailed analysis of SSPO-based bifurcation phenomena as shown in Figs. 5 and 8.

B O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O


The exploration of meditation in the neuroscience of attention and consciousness Abstract Many recent behavioral and neuroscientific studies have revealed the importance of investigating meditation states and traits to achieve an increased understanding of cognitive and affective neuroplasticity, attention and self-awareness, as well as for their increasingly recognized clinical relevance. The investigation of states and traits related to meditation has especially pronounced implications for the neuroscience of attention, consciousness, self-awareness, empathy and theory of mind. In this article we present the main features of meditation-based mental training and characterize the current scientific approach to meditation states and traits with special reference to attention and consciousness, in light of the articles contributed to this issue. Meditation can be conceptualized as a family of complex emotional and attentional regulatory practices, in which mental and related somatic events are affected by engaging a specific attentional set. Many recent behavioral, electroencephalographic and neuroimaging studies have revealed the importance of investigating states and traits related to meditation in order to achieve an increased understanding of cognitive and affective neuroplasticity, attention and selfawareness, as well as for their possible clinical implications (Cahn and Polich 2006; Lutz et al. 2008a) .. The regulation of attention is a central feature of different meditation methods (Davidson and Goleman 1977) , and meditation practices can be usefully classified into two main styles-focused attention (FA) and open monitoring (OM)-depending on how the attentional processes are directed (Cahn and Polich 2006; Lutz et al. 2008a ). In the FA ('concentrative') style, attention is focused on a given object in a sustained manner. The second style, OM ('mindfulness-based') meditation, involves the non-reactive monitoring of the content of ongoing experience, primarily as a means to become reflectively aware of the nature of emotional and cognitive patterns. Mindfulness refers to an alert and open mode of perceiving and monitoring all mental content from moment to moment, including perceptions, sensations, cognitions and affects (Kabat-Zinn 2003) .

O O O B O O O O B O B O O O O O O O O O O O O O B O O O O O O O O O O O O B B O B O O O O O O O O O O O O O O O O O B O O O O O O O O B B B O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O B O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O B B O O O O O O O O O O O O O O O O O O O O O O B O O O O O O B O O O O O O O B O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Steady

state

analysis

of

Boolean

molecular

network

models

via

model

reduction

and

computational

algebra

A

key

problem

in

the

analysis

of

mathematical

models

of

molecular

networks

is

the

determination

of

their

steady

states.

The

present

paper

addresses

this

problem

for

Boolean

network

models,

an

increasingly

popular

modeling

paradigm

for

networks

lacking

detailed

kinetic

information.

For

small

models,

the

problem

can

be

solved

by

exhaustive

enumeration

of

all

state

transitions.

But

for

larger

models

this

is

not

feasible,

since

the

size

of

the

phase

space

grows

exponentially

with

the

dimension

of

the

network.

The

dimension

of

published

models

is

growing

to

over

so

that

efficient

methods

for

steady

state

determination

are

essential.

Several

methods

have

been

proposed

for

large

networks,

some

of

them

heuristic.

While

these

methods

represent

a

substantial

improvement

in

scalability

over

exhaustive

enumeration,

the

problem

for

large

networks

is

still

unsolved

in

general.

Results:

This

paper

presents

an

algorithm

that

consists

of

two

main

parts.

The

first

is

a

graph

theoretic

reduction

of

the

wiring

diagram

of

the

network,

while

preserving

all

information

about

steady

states.

The

second

part

formulates

the

determination

of

all

steady

states

of

a

Boolean

network

as

a

problem

of

finding

all

solutions

to

a

system

of

polynomial

equations

over

the

finite

number

system

with

two

elements.

This

problem

can

be

solved

with

existing

computer

algebra

software.

This

algorithm

compares

favorably

with

several

existing

algorithms

for

steady

state

determination.

One

advantage

is

that

it

is

not

heuristic

or

reliant

on

sampling,

but

rather

determines

algorithmically

and

exactly

all

steady

states

of

a

Boolean

network.

The

code

for

the

algorithm,

as

well

as

the

test

suite

of

benchmark

networks,

is

available

upon

request

from

the

corresponding

author.The

algorithm

presented

in

this

paper

reliably

determines

all

steady

states

of

sparse

Boolean

networks

with

up

to

nodes.

The

algorithm

is

effective

at

analyzing

virtually

all

published

models

even

those

of

moderate

connectivity.

The

problem

for

large

Boolean

networks

with

high

average

connectivity

remains

an

open

problem.Boolean

network

(BN)

models

are

widely

used

in

molecular

and

systems

biology

to

capture

coarse-grained

dynamics

of

a

variety

of

regulatory

networks,

with

a

particular

focus

on

features

such

as

steady

state

behavior

One

advantage

of

discrete

models

of

this

type

is

that,

for

small

models,

the

entire

dynamics

can

be

explored

by

exhaustive

enumeration

of

all

state

transitions.

Since

the

size

The

capability

to

analyze

the

attractors

of

discrete

dynamic

models

of

biological

networks

is

a

key

technology

in

any

systems

biology

toolkit

that

incorporates

this

popular

type

of

model.

This

capability

needs

to

include

steady

state

analysis

as

well

as

the

determination

of

periodic

points

of

larger

periods.

And

it

needs

to

apply

to

models

that

allow

an

arbitrary

(finite)

number

of

states

for

its

variables,

such

as

logical

models.

In

this

paper,

we

have

focused

on

Boolean

networks

as

the

model

type

most

commonly

used

currently.

And

we

have

focused

only

on

steady

state

analysis,

at

the

exclusion

of

periodic

limit

cycles.

As

is

the

case

in

many

situations,

algorithms

available

for

this

purpose,

some

of

which

we

used

here

for

comparison,

perform

well

on

some

types

of

models

and

not

so

well

on

others.

For

instance,

for

Kaufmann

networks

with

connectivity

the

method

in

outperforms

all

other

methods,

including

ours.

The

method

in

is

generally

slower

than

our

method

in

computing

steady

states,

but

has

the

added

capability

that

it

also

finds

limit

cycles

of

larger

lengths,

which

our

method

is

not

currently

equipped

to

do..

We

have

used

three

types

of

networks

for

benchmarking:

Kauffman

networks,

power

law

networks,

and

published

networks.

Kauffman

networks

are

commonly

used

for

this

purpose,

but

they

don't

capture

all

properties

of

molecular

networks,

which

include

a

power

law

distribution

of

node

connectivities.

Our

analysis

of

published

networks

shows

that

some

of

them

have

high

average

connectivity,

not

generally

considered

in

theoretical

studies.

These

pose

serious

challenges

to

computational

methods,

as

we

demonstrate.

As

more

large

published

networks

become

available,

they

will

represent

the

most

important

suite

of

benchmark

models

to

be

used,

in

our

opinion..

We

believe

that

this

study

also

holds

another

important

lesson.

Our

method

is

a

combination

of

two

methods,

neither

one

of

which

performs

particularly

well

when

applied

on

its

own

(see

Additional

file

In

combination,

however,

they

are

quite

powerful:

model

reduction

plus

polynomial

algebra.

This

might

point

towards

a

general

strategy

for

other

algorithms

of

this

type.

Nonetheless,

as

our

calculations

show,

the

challenge

of

finding

steady

states

is

far

from

solved

in

general,

even

for

existing

published

models.

Thus,

much

work

remains

to

be

done.

The

method

we

propose

for

steady

state

analysis

is

a

combination

of

network

reduction/transformation

and

computational

algebra

(see

Figure

The

reduction

technique

we

use

is

based

on

results

in

In

it

was

shown

that

any

Boolean

network

can

be

"transformed"

into

an

AND-NOT

network,

namely

a

network

whose

Boolean

functions

are

all

of

the

form

y

y

where

y

i

{x

i

¬x

i

The

AND-NOT

network

has

the

property

that

its

steady

states

are

in

one-to-one

correspondence

with

the

steady

states

of

the

original

network.

Furthermore,

the

one-to-one

correspondence

between

steady

states

is

algorithmic.

In

the

authors

proposed

a

method

to

reduce

an

AND-NOT

network

to

another,

smaller

AND-NOT

network

in

polynomial

time,

in

such

a

way

that

the

steady

states

of

the

original

and

the

reduced

network

are

in

one-to-one

correspondence,

in

a

constructive

way.

This

reduction

algorithm

looks

for

motifs

(e.g.

feed-forward

loops)

in

the

wiring

diagram

and

removes

nodes

in

such

motifs;

the

reduction

stops

when

there

are

no

more

motifs

to

be

reduced

(attempting

to

do

further

reductions

would

destroy

the

correspondence

of

steady

states).

Once

the

reduced

network

is

constructed,

one

can

compute

its

steady

states

by

converting

the

Boolean

functions

into

polynomial

functions

and

then

solving

a

system

of

polynomial

equations,

as

explained

above.

The

computational

algebra

technique

is

based

on

The

idea

is

that

by

computing

a

Gröbner

basis

(a

special

set

of

polynomials

with

the

same

roots

as

the

original

equations),

it

is

possible

to

find

the

roots

of

the

system

of

polynomial

equations

using

a

generalized

version

of

Gaussian

elimination..

The

correspondence

between

Boolean

and

polynomial

functions

is

accomplished

via

the

"dictionary"

x

y

x

y,

x

y

x

y

xy,

¬x

x

The

correspondence

is

unique

if

we

limit

the

degree

with

which

each

variable

appears

in

the

polynomial

function

to

since

any

function

K

n

K

can

be

represented

uniquely

as

a

polynomial

function

that

is

square-free,

that

is,

in

which

every

variable

appears

with

exponent

The

algorithm

is

summarized

in

the

following

pseudocode

and

a

more

detailed

description

follows.

The

source

code

can

be

found

at

ADAM..

Compute

p

=polynomial

representation

of

h

Solve

the

equations

h

i

x

i

using

computational

algebra

(i.e.

compute

the

Gröbner

basis

to

perform

a

generalized

version

of

Gaussian

elimination)

and

let

L

{s

s

r

be

the

set

of

solutions

Use

backtracking

to

compute

the

steady

states

of

g:

L

{s

s

r

Project

each

s

j

to

its

first

n

coordinates

to

obtain

s

j

The

input

of

our

algorithm

is

an

n−dimensional

Boolean

network

f

(f

f

n

In

Step

we

use

the

formulas

from

to

compute

an

AND-NOT

network

g

(g

g

m

with

m

n,

which

has

the

same

number

of

steady

states

as

f

The

idea

is

to

introduce

variables

to

rewrite

the

Boolean

operations

using

only

the

operators

AND

and

NOT;

for

example,.

can

be

written

as

f

¬x

¬x

where

f

¬x

¬x

Furthermore,

the

steady

states

of

f

are

given

by

projecting

the

steady

states

of

g

to

their

first

n

coordinates.

In.

Step

we

simply

consider

the

wiring

diagram

of

g,

which

is

a

signed

directed

graph

that

encodes

which

variable

depends

on

which

others

and

whether

the

interactions

are

activating

or

inhibiting.

In

Step

we

use

the

algorithm

from

to

reduce

the

wiring

diagram

of

g

to

another

signed

directed

graph,

W

Then,

in

Step

we

construct

the

AND-NOT

network

that

has

W

as

its

wiring

diagram,

h

(h

h

l

the

steady

states

of

g

can

be

computed

from

the

steady

states

of

h

by

backtracking

In

Step

we

compute

the

polynomial

representation

of

h.

This

is

done

by

replacing

¬x

i

with

x

i

and

x

i

x

j

with

x

i

x

j

as

explained

earlier.

In

Step

we

solve

the

system

of

polynomial

equations

h

i

x

i

i

l;

this

is

done

using

tools

from

computational

algebra

as

done

in

The

solutions

of

the

system,

L

{s

s

r

will

also

be

solutions

of

h.

In

Step

we

use

backtracking

to

compute

the

steady

states

of

g,

L

{s

s

r

And

finally,

in

Step

we

project

each

s

j

to

its

first

n

coordinates

and

obtain

the

steady

states

of

f

(See

Additional

file

for

an

example

and

Additional

files

and

for

the

code

version

used

for

this

publication).

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Modelling process and optimization of EMC filters for power electronics applications Abstract. The paper proposes an approach for easy and fast modelling and optimization of power electronics structures. It focuses on the EMC filter design. To achieve this task for electrical drives, a full EMC modelling of the application is defined by combining time simulation, FFT and automatic frequency modelling. The automatic modelling gives also automatically the model gradients. This process is very generic, fast and systematic, and can be used with any optimisation algorithm, using gradients or not. Therefore, the model can be used to optimize the EMC filter, but also can help in choosing its topology, according to the technological choices of the aircraft power electronics specifications. There may be a great impact of the electromagnetic behaviour due to the power electronics of the electrical systems in several applications. In aircraft application, global weight, cost and volume of the equipment are also important complementary constraints. So, there is a strong need in helping the power electronics designers to choose among various technological possibilities, and to know the impact of these choices on all these constraints. The electromagnetic compatibility (EMC) filter usually represents roughly 30% of the cost and volume of a power electronics converter; so, it is very important to optimize it (Fig. 1) . The impact of the converter control law, semiconductor choice, interconnection design, cable selection and placement, electrical machine characteristics… should be perfectly known to reach a good system design. The paper proposes an aid in the frequency modelling of the drive elements, in the frequency domain, including all key parameters for sizing aim; and so, a way to optimize the filter using different algorithms available in Cades® framework [1] (see Fig. 2 ), but also in the Matlab® environment. It becomes especially important to manage the filter design and the impact of the system volume, weight and cost, specifically in aircraft applications. The use of a simple model, based on disturbance sources allows obtaining quickly an estimation of the EMC spectrum of an electrical drive, including the influence of all the parameters involved in the design: control, power package, busbar, harnesses and machine. The paper proposes a way to easy achieve such a modelling, allowing to carry out any optimisation algorithm thanks to automatic gradient computation. The automatic modelling reduces the modelling task, so allow optimizing on several power electronics architectures and several equivalent circuits for every architecture.

O O O B O O O O O O O O O O O O O O O O O O O B O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O B I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Threshold Anonymous Password-Authenticated Key Exchange Secure against Insider Attacks An anonymous password-authenticated key exchange (PAKE) protocol is designed to provide both password-only authentication and client anonymity against a semi-honest server, who honestly follows the protocol. In INDOCRYPT2008, Yang and Zhang [26] proposed a new anonymous PAKE (NAPAKE) protocol and its threshold (D-NAPAKE) which they claimed to be secure against insider attacks. In this paper, we first show that the D-NAPAKE protocol [26] is completely insecure against insider attacks unlike their claim. Specifically, only one legitimate client can freely impersonate any subgroup of clients (the threshold t > 1) to the server. After giving a security model that captures insider attacks, we propose a threshold anonymous PAKE (called, TAP + ) protocol which provides security against insider attacks. Moreover, we prove that the TAP + protocol has semantic security of session keys against active attacks as well as insider attacks under the computational Diffie-Hellman problem, and provides client anonymity against a semi-honest server, who honestly follows the protocol. Finally, several discussions are followed: 1) We also show another threshold anonymous PAKE protocol by applying our Rationale to the non-threshold anonymous PAKE (VEAP) protocol [23]; and 2) We give the efficiency comparison, security consideration and implementation issue of the TAP + protocol. key words: password-authenticated key exchange, passwords, on-line/offline dictionary attacks, anonymity, insider attacks, provable security In order to establish secure channels between parties, one of the ways is to use an authenticated key exchange (AKE) protocol that allows the involving parties to authenticate each other and then share an authenticated session key to be used for subsequent cryptographic algorithms (e.g., AES-CBC or MAC). Note that the Diffie-Hellman protocol [8] is a key exchange that does not provide authentication at all.. Adding authentication to a (plain) key exchange protocol is crucial because it can prevent an active adversary, who can completely control the communications, from getting any useful information about the session key. In particular, human-memorable passwords (e.g., 4-digit pin-code or alphanumerical passwords) are commonly used for authentication rather than high-entropy keys because of their convenience in use. Many password-based AKE protocols (see [11] for the exclusive list) have been extensively investigated for a long time where a client remembers a short pass- word and the corresponding server holds the password or its verification data that is used to verify the client's knowledge of the password. However, one should be very careful about two attacks on passwords: on-line and off-line dictionary attacks. Let us take for example a simple challenge-response password authentication protocol [21] where a client and a server share a password pw. In the protocol, the server sends a challenge c to the client, who computes a response r = H(c, pw) and sends back r to the server where H is a hash function. After receiving r, the server authenticates the client if the received r is equal to its own computation H(c, pw). The on-line dictionary attacks are performed by an adversary who impersonates one party (i.e., the client in the above example) so that the adversary can sieve out possible password candidates one by one. On the other hand, the off-line dictionary attacks are performed off-line and in parallel where an adversary exhaustively enumerates all possible password candidates, in an attempt to determine the correct one, by simply guessing a password and verifying that with additional information. In the above example, an adversary can find out the correct password pw with offline dictionary attacks by trying all password candidates pw until it satisfies r = H(c, pw ). While on-line attacks are applicable to all of the password-based protocols equally, they can be prevented by having a server take appropriate countermeasures (e.g., lock-up accounts for 10 minutes after 3 consecutive failures of passwords). But, we cannot avoid off-line attacks by such countermeasures mainly because these attacks can be done off-line and independently of the party. After analyzing the D-NAPAKE protocol [26] , we showed that it is completely insecure against insider attacks unlike the authors' claim. Specifically, only one legitimate client can freely impersonate any subgroup of clients (the threshold t > 1) to the server. In order to capture insider attacks, we gave a formal model where an adversary can control less than the threshold number of clients by invoking the Register-query. Also, we proposed a threshold anonymous PAKE (called, TAP + ) protocol that provides security against insider attacks. Moreover, we proved that the TAP + protocol is AKE-secure against active attacks as well as insider attacks under the computational Diffie-Hellman problem, and provides client anonymity against a semi-honest server, who honestly follows the protocol. Finally, several discussions were followed: 1) We also showed another threshold anonymous PAKE protocol by applying our Rationale to the (non-threshold) anonymous PAKE (VEAP) protocol [23] ; and 2) We gave the efficiency comparison, security consideration and implementation issue of the TAP + protocol. As we discussed in Sect. 5.3 , an open (and challenging) problem is to design a threshold anonymous PAKE protocol that is secure against insider attacks and has a tight security reduction (independent of the number of clients n) in the probability of on-line dictionary attacks. We also leave it as an open issue to deal with potential Denial-of-Service (DoS) attacks to the client group because, if an adversary impersonates any client in a threshold anonymous PAKE protocol, the server cannot identify the client exactly as well as restrict his/her further access.

O O B I I O O B I O O B I I O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I B O O O B B I B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Improved detection of fluorescently labeled microspheres and vessel architecture with an imaging cryomicrotome Abstract Due to spectral overlap, the number of fluorescent labels for imaging cryomicrotome detection was limited to 4. The aim of this study was to increase the separation of fluorescent labels. In the new imaging cryomicrotome, the sample is cut in slices of 40 lm. Six images are taken for each cutting plane. Correction for spectral overlap is based on linear combinations of fluorescent images. Locations of microspheres are determined by using the system point spread function. Five differently colored microspheres were injected in vivo distributed over two major coronaries, the left anterior descending and left circumflex artery. Under absence of collateral flow, microspheres outside of target perfusion territories were not found and the procedure did not generate false positive detection when spectral overlap was relevant. In silicogenerated microspheres were used to test the effect of background image, transparency correction, and color separation. The percentage of microspheres undetected was 2.3 ± 0.8% in the presence and 1.5 ± 0.4% in the absence of background structures with a density of 900 microspheres per color per cm 3 . The image analysis method presented here, allows for an increased number of experimental conditions that can be investigated in studies of regional myocardial perfusion. Labeled microspheres have been used for more than half a century to quantify perfusion distribution, either over the circulatory system as a whole or within an organ [14] . In this method, labeled microspheres are injected into the circulation either as a bolus or by continuous infusion over a period of time [12] . The working principle is that these microspheres, typically with a diameter around 15 lm, travel with the blood stream and become trapped in the microcirculation since they cannot pass the capillaries. Ultimately, they shift from the capillary lumen to the interstitium [4, 10] . The number of microspheres in a certain region, relative to the total amount of injected microspheres and weighted by the blood flow at the site of injection, represents the regional perfusion in volume flow per unit mass.. Several methods have been developed permitting the distinction of different labels. The classical labels were radioactive [3] , colored [9] or following recent development, fluorescent [8] . Tissue samples for measurements were originally obtained by cutting the tissue in the area of interest into pieces of 0.1-2 cm 3 depending on the study aim [1] . The radioactivity in these samples was then measured directly [6] or these were processed to determine the total fluorescence or number of microspheres [17] .. In a recently introduced and more advanced method, an imaging cryomicrotome is used that allows the position of individual microspheres to be detected [11] . In this method, the tissue block under investigation is frozen and sliced with a cryomicrotome at a preset thickness, e.g., 40 lm at a time. After each cut, fluorescent images are taken with a high-resolution digital camera. Image processing then yields the x-y-z coordinates of the microspheres [2, 11] .. The classical and cryomicrotome method share a commonality in that the tissue examined is destroyed. The information retained in the classical method has a spatial resolution of the tissue sample size which has an under limit of 0.1 g, while in the cryomicrotome the resolution is of the voxel size of the camera and slice thickness, which is a factor 1 9 10 6 higher. Moreover, the region of interest for calculation of microsphere density can be selected at will in the cryomicrotome method but not in the classical methods. In addition, injection of fluorescent cast material into the vasculature prior to freezing allows detection of the arterial tree structures down to small arterioles with a diameter of 20-40 lm [15, 16] . Hence, the imaging cryomicrotome enables the combined measurements of blood vessel structure and flow distribution within an organ. However, until now, only four different fluorescent labels could be distinguished with the imaging cryomicrotome method [11] , which is a limitation compared to the earlier radioactive labeled methods where up to nine different labels could be detected.. The purpose of this study was to increase the number of differently labeled fluorescents. We present a method to improve the fluorescent color separation by correcting for spectral overlap based on a linear combination of the images. Our approach permits differentiation of six fluorescent labels, of which five are used for the microspheres and one for the infused casting material. The proposed method was validated both in silico and with actual data obtained from canine hearts. We demonstrated the feasibility of using different filter combinations to distinguish five separate microsphere colors in addition to the fluorescently labeled vascular tree. This allows high-resolution spatial measurements of local perfusion for five different experimental conditions in the same organ that can additionally be closely related to the detected vascular structure. We presented a method to correct for spectral overlap of fluorescent emission light, which allows the use and successful separation of a larger number of fluorescent labels in imaging cryomicrotome applications. With our image processing algorithms, we successfully distinguished one color for the casting material and an additional five colors for microspheres, thereby increasing the number of fluorescent colors successfully detected from 4 to 6. An increase in labels is important, since it enlarges the maximum number of experimental conditions that can be The in silico simulations demonstrated that over 98% of the microspheres were correctly counted for a realistic range of microsphere densities. The number of missed counts was only 1.5 ± 0.4% for high microsphere density (900 spheres/cm 3 ) and decreased to 0.9 ± 0.8% for a lower concentration (500 spheres/cm 3 ). With background images added, the number of missed microspheres increased to 2.3 ± 0.8 and 1.8 ± 1.3%, respectively. The error was not specific for any color.. The data obtained from frozen canine hearts showed a clear demarcation zone between the LAD and LCX perfusion territories indicating the absence of false positive detection of microspheres. Although, the number of saddle points and high intensity observations was very low, it increased with the wavelength of the emission light. This is due to the widening of the point spread function as a consequence of the lower attenuation coefficient of the tissue for longer wavelengths in combination with the chromatic aberration of the lens system.

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I I I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O


Sleep quality, social well-being, gender, and inflammation: an integrative analysis in a national sample Social isolation and poor sleep quality are independent predictors of poor health outcomes and increased biological risk for disease. We previously found in a small sample of older women that the presence of social ties compensated for poor sleep in associations with the inflammatory protein interleukin 6 (IL-6). The current study extended those findings to a national sample of middle-aged and older men and women. Using both subjective and objective sleep assessments, we found that in men, but not in women, social engagement moderated the association of subjective sleep complaints with both IL-6 and the soluble adhesion molecule E-selectin. Social engagement also moderated the link between sleep efficiency-assessed by actigraphy-and IL-6 levels in men, but not in women. These results extend our previous work and bolster the suggestion that positive psychological functioning may compensate for other risk factors in predicting advantageous profiles of biological risk in aging adults. Circulating levels of inflammatory proteins, which have been cross-sectionally and prospectively linked to a range of disease conditions, [1] [2] [3] are influenced by myriad social, psychological, and behavioral factors. Studies documenting these relationships typically focus on the independent association of one or more of these determinants with inflammatory proteins. None of these determinants exists in isolation of the others, however, and it is therefore important to consider the ways in which they may interact in predicting inflammation. This study weaves together three separate lines of inquiry involving sleep and social factors and examines the points at which they intersect in their associations with inflammation.. First, studies using multiple assessment techniques and approaches have established robust links between sleep and inflammation. Major depression, for example, is often associated with increased circulating levels of inflammatory proteins 4, 5 and significantly impaired sleep, 6 and recent evidence suggests that impaired sleep may be a better predictor of inflammation than the presence or absence of major depression. 7 Similarly, adults with excessive daytime sleepiness have higher circulating levels of IL-6 than those with better sleep. 8 Experimental studies involving sleep restriction report higher levels of IL-6 9,10 along with increased expression of genes linked to increased inflammation. 11 In community dwelling adults, poor sleep is associated with higher circulating levels of IL-6 12 and with increased release of inflammatory proteins from stimulated lymphocytes. 13 Collectively, these results show that impaired or curtailed sleep, achieved either naturally or experimentally, predict higher circulating levels of inflammatory proteins.. The second line of inquiry focuses on the association of social well-being and inflammation. Isolation from social contact has been linked with increased risk of mortality in epidemiological studies [14] [15] [16] and with impaired host defense in experimental studies. 17 Recent evidence suggests that loneliness is associated with increased activity in genetic pathways regulating the production of inflammatory proteins, such as NF-B. 18 A complementary literature has shown that strong social relationships in women with ovarian cancer 19 and social engagement in older community dwelling women 20 predict lower levels of IL-6. These studies suggest that social ties are important predictors of inflammation; the latter studies in particular suggest that high levels of social well-being may have compensatory properties, predicting lower levels of inflammation in those at risk of greater inflammation due to illness or advancing age.. Finally, recent studies from Cacioppo et al. suggest associations between social relationships and sleep. Specifically, individuals who report high levels of loneliness also had reduced sleep efficiency as assessed by self report 21 or using the Nightcap sleep system. 22 Another study using daily diary assessments showed that loneliness predicted impaired daytime functioning independently of the amount of sleep the prior night. 23 One hypothesis stemming from this work is that loneliness is evolutionarily linked to feelings of vulnerability, one result being increased nighttime vigilance, which in turn reduces the restorative quality of sleep. 24 These three lines of inquiry converge on the hypothesis that sleep and social relationships, which are independently linked to inflammation and to one another, may interact in predicting inflammation. We tested this hypothesis in a sample of older women living in Wisconsin, and we found that while greater sleep efficiency and higher levels of social engagement independently predicted lower levels of IL-6, the presence of one compensated for the lack of the other; the only women in the sample at risk of higher levels of IL-6 were those with low sleep efficiency and low social engagement. 25 We now extend this research to a national sample of middle-aged and older men and women-the Survey of Mid-Life in the United States (MIDUS) 26 -that combines measures of subjective and objective sleep quality. We also extend these analyses with measurement of E-selectin, a soluble adhesion molecule that, like IL-6, is implicated in age-related morbidity, especially cardiovascular disease, [27] [28] [29] [30] and is elevated by reduced sleep related to sleep apnea 31 and experimental sleep deprivation. 32 We hypothesized that poor sleep quality would predict higher levels of IL-6 and E-selectin, while greater social engagement would predict lower levels. More centrally, we hypothesized that sleep quality and social engagement would interact so that higher levels of social engagement would compensate for poor sleep quality-and vice versa-in predicting inflammation. Finally, as noted below, we observed significant differences between men and women in sleep, inflammation, and their interaction. Therefore, consistent with other studies examining links between social factors and inflammation, 33 we conducted separate analyses for men and women. The central hypothesis of the current study was that sleep quality and social well-being would interact in predicting inflammation in a national sample of middle-aged men and women. The results provide support for this hypothesis. The association between subjective sleep quality and inflammation was (Table 5) is illustrated here using the top ("high relations") and bottom ("low relations") tertiles of scores from the positive relations scale.. significantly weaker in male participants with higher scores on the positive relations with others scale. Positive relations with others also moderated the association of objectively assessed sleep efficiency and IL-6. We previously reported that positive relations with others moderated the relationship between sleep efficiency, assessed using the Nightcap system, and IL-6 in older women. 25 We observed the same pattern of results in the current study in additional analyses of women over the age of 60, although the results were not statistically significant (data not shown). In sum, the current results extend our earlier work to a national sample, and they suggest that across a 50-year age range, social engagement may buffer against the proinflammatory effects of poor sleep (and good sleep may compensate for low levels of social engagement), particularly in men.. As expected, poorer subjective sleep quality, as measured by the PSQI, predicted higher levels of both IL-6 and E-selectin in men and women. A number of studies have reported links between poor subjective sleep quality and higher circulating levels of inflammatory proteins, 13, 45, 46 but to the best of our knowledge, this study is the first to document this association in a national sample with broad demographic representation. These associations were also independent of an array of health status and health behavior measures, including factors that are strongly linked to inflammation, such as obesity. 47, 48 Subjective sleep quality is thus an important independent predictor of biological processes related to age-related disease.. In the subsample that provided actigraphy data, longer sleep durations, shorter latencies to fall asleep, and greater sleep efficiency all predicted lower levels of IL-6 in women, but not in men, in bivariate analyses; greater sleep efficiency was also associated with lower levels of E-selectin in women. In multivariate analyses, however, only sleep efficiency continued to predict IL-6 and E-selectin after adjustments for demographic characteristics, and those associations were eliminated by further adjustment for health status and health behavior. Age is the most likely factor to account for the sleep duration and sleep latency results. IL-6 in particular rises with age, 1 and older adults typically sleep less than younger adults. 49 Age thus represents a likely confound for these associations. With regard to sleep efficiency, obesity was the strongest predictor of both IL-6 and E-selectin among the health status variables, and as it is strongly linked to disturbed sleep, particularly due to increased risk of sleep apnea, 50 obesity is the most likely mediator of the association between sleep efficiency and inflammation. It is worth noting that the relationship between sleep efficiency and inflammation was the most robust of the actigraphic measures. This is consistent with the research on sleep and loneliness, which centers on differences in sleep quality without differences in sleep quantity, 24 and with other lines of work examining the links among social factors, sleep, and health more broadly. 51 We also found in bivariate analyses that greater subjective sleep quality, greater sleep efficiency, and reduced sleep latency in men were all associated with greater social engagement. These complement earlier studies reporting poorer sleep in young and older adults with higher levels of loneliness, [21] [22] [23] and suggest that the link between sleep and social contact may involve not merely the presence or absence of loneliness but also the presence or absence of high levels of social engagement. There is rising interest in the positive end of the spectrum of psychological functioning, including flourishing, and the extent to which positive functioning is an independent predictor of mental and physical health above and beyond the lack of negative functioning. 52 Nevertheless, this relationship was not a central focus of the current study, and the extent to which these associations are explained by other factors, such as demographic characteristics of health-related variables, remains to be determined.. There were marked gender differences in sleep quality and inflammation in the MIDUS sample, and this is consistent with a number of earlier studies. Women typically have a greater number of subjective sleep complaints than men, but when sleep quality is assessed objectively using polysomnography or actigraphy, women are often found to sleep better than men. 49, [53] [54] [55] Indeed, while women had significantly higher PSQI scores in the current study, indicating greater sleep pathology, actigraphic assessments showed that compared to men, women took less time to fall asleep, slept longer, and slept for a greater proportion of the night. Men in this sample also had higher levels of E-selectin than women, and this is consistent with other studies. 27, 56 Interestingly, while bivariate analyses showed that better subjective and objective sleep quality was more likely to predict lower levels of IL-6 and E-selectin in women, the moderating effect of social engagement on the link between sleep quality and inflammation was apparent only in men. The reasons for this pattern of results are not clear. In some instances, links between psychosocial factors and health are stronger in women. 46 On the other hand, there is scant literature on interactive associations among psychological and behavioral factors in predicting inflammation. The current results are similar to those from an earlier study in which exposure to chronic discrimination was linked to higher levels of E-selectin in men from the MIDUS study in spite of the fact that women reported greater exposure to discriminatory treatment. 35 Interpretation of these results should be tempered by several limitations of the study. First and foremost, these analyses are cross-sectional, so it is not possible to determine the causal association among the key variables. This is particularly relevant for the link between sleep and inflammation, as inflammatory proteins such as IL-6 are known to impair sleep 57 and increase fatigue. 58, 59 In addition, while this sample was racially diverse, much of that diversity comes from a regional sample of African Americans, and there may be differences between this sample and those from other regions of the country. Finally, inflammatory proteins were only assessed once, which, given variability in their levels within individuals, might produce inaccurate estimates of each person's circulating levels. Nevertheless, such variability would be expected to reduce the likelihood of detecting associations, meaning that the strength of the relationships observed may be underestimated.. In spite of these limitations, the present study adds to the literature on links between sleep and inflammation, social engagement and inflammation, and social engagement and sleep. It also extends our earlier work on interactive associations between sleep and social engagement to a national sample of middle-aged and older adults. These findings underscore the importance of considering the ways in which factors in multiple domains of experience within the same individual interact to affect biological processes related to health. They also highlight the role of positive psychological functioning in the maintenance of advantageous profiles of biological risk as well as the ways in which positive functioning may compensate for the presence of other risk factors. Descriptive statistics for all variables are shown in Table 1 ; results for men and women are shown separately. Men and women differed significantly on most measures, with the exception of IL-6, depressive symptoms, exercise, BMI, and use of blood pressure medication. Bivariate associations among key variables in men and women are shown in Table 2 . Higher PSQI global scores, indicating poorer subjective sleep quality, were associated with shorter actigraphic sleep duration in women, greater sleep latency, and reduced sleep efficiency. Higher global scores also predicted higher levels of both IL-6 and E-selectin. Greater sleep duration and sleep efficiency and shorter sleep latencies predicted lower levels of IL-6 in women, but not in men; greater sleep efficiency also predicted lower E-selectin levels in women. Finally, higher scores on positive relations with others predicted lower levels of IL-6 and E-selectin in women, but not in men. Tables 3 and 4 display the results of multivariate regression analyses involving PSQI global scores. In men, but not in women, PSQI global scores and its interaction with positive relations with others were significantly associated with IL-6 ( Table 3 ) and Eselectin (Table 4 ) in the base model adjusting for demographic characteristics (model 1) and the full model adjusting for health status, health behavior, and positive and negative affect (model 2). In particular, the interaction showed that as subjective sleep quality declined (higher PSQI scores), IL-6 and Eselectin levels were less likely to rise in men reporting higher positive relations scores (Figs. 1 and 2 ). Positive relations with others was positively associated with IL-6 and E-selectin in men but only after the interaction term was included in the model, suggesting a complex relationship among these predictor variables.

B I B I O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O B O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O B I O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O B O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O B O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B O O O O O O O O O O O O O O O O O O O O O