Completeness of bounded model checking temporal logic of knowledge

In order to find the completeness threshold which offers a practical method of making bounded model checking complete, the over-approximation for the complete threshold is presented. First, a linear logic of knowledge is introduced into the past tense operator, and then a new temporal epistemic logic LTLKP is obtained, so that LTLKP can naturally and precisely describe the system＇s reliability. Secondly, a set of prior algorithms are designed to calculate the maximal reachable depth and the length of the longest of loop free paths in the structure based on the graph structure theory. Finally, some theorems are proposed to show how to approximate the complete threshold with the diameter and recurrence diameter. The proposed work resolves the completeness threshold problem so that the completeness of bounded model checking can be guaranteed.

兴于诗 立于礼 成于乐

体验幸福是需要素养的。如今我们的物质水平有了很大提高,但很多人并不觉得幸福,这是为什么呢?子曰:“兴于诗,立于礼,成于乐。”(《论语·泰伯篇》)——孔子说:“修身明志,让人生充满激情,当以诗成之;立身处世,在与社会和他人相处时知进退之道,当以礼成之;培养高尚情操与艺术品质,当以乐成之。”

Quantitative Relationship Between Simultaneous Color Contrast and Hue Difference in Complex Displays

To investigate quantitatively one of the parametric effects——simultaneous color contrast on color appearance and color difference evaluation in complex displays, a set of center/surround combinations of color stimuli were displayed on a color monitor and the perceived color shifts of test targets induced by its surrounds were measured using binocular matching method while systematically varying hue difference between target and surround. When the hue difference increased, the magnitude of color shift in test target decreased, but the deflection angle of color shift vector from constant hue line increased. Regression analyses of experimental data indicated that the relationship between hue angle difference and the magnitude of perceived color shifts could be described quantitatively by an exponential function, and a linear function could describe quantitative relationship between hue angle difference and deflection angle of color shift vector from constant hue line.

Adaptive double-threshold energy detection algorithm for cognitive radio

Due to the fact that the conventional spectrum sensing algorithm is susceptible to noise, an adaptive double-threshold energy detection algorithm for a cognitive radio is proposed. Based on double-threshold energy detection, the algorithm can adaptively switch between one-round sensing and two-round sensing by comparing the observations with the pre-fixed thresholds. Mathematical expressions for the probability of detection, the probability of false alarm, and the sensing time are derived. The relationships including signal to noise ratio （SNR） vs. the probability of detection and SNR vs. the sensing time are plotted using Monte Carlo simulation and the algorithm is verified in a real cognitive system based on GNU Radio and universal software radio peripheral （USRP）. Simulation and experimental results show that, compared with the existing spectrum sensing method, the proposed algorithm can achieve a higher probability of detection within a reasonable sensing time.

Differential effects of physical activity and sleep duration on cognitive function in young adults

Purpose: Although exercise and sleep duration habits are associated with cognitive function, their beneficial effects on cognitive function remain unclear. We aimed to examine the effect of sleep duration and daily physical activity on cognitive function, elucidating the neural mechanisms using near-infrared spectroscopy(NIRS).Methods: A total of 23 healthy young adults(age 22.0 ± 2.2 years) participated in this study. Exercise amount was assessed using a uniaxial accelerometer. We evaluated total sleep time(TST) and sleep efficiency by actigraphy. Cognitive function was tested using the N-back task, the Wisconsin Card Sorting Test(WCST), and the Continuous Performance Test—Identical Pairs(CPT-IP), and the cortical oxygenated hemoglobin levels during a word fluency task were measured with NIRS.Results: Exercise amount was significantly correlated with reaction time on 0- and 1-back tasks(r = —0.602, p = 0.002; r = —0.446, p = 0.033,respectively), whereas TST was significantly correlated with % corrects on the 2-back task(r = 0.486, p = 0.019). Multiple regression analysis,including exercise amount, TST, and sleep efficiency, revealed that exercise amount was the most significant factor for reaction time on 0- and 1-back tasks(b = —0.634, p = 0.002; b = —0.454, p = 0.031, respectively), and TST was the most significant factor for % corrects on the 2-back task(b = 0.542, p = 0.014). The parameter measured by WCST and CPT-IP was not significantly correlated with TST or exercise amount. Exercise amount, but not TST, was significantly correlated with the mean area under the NIRS curve in the prefrontal area(r = 0.492, p = 0.017).Conclusion: Exercise amount and TST had differential effects on working memory and cortical activation in the prefrontal area. Daily physical activity and appropriate sleep duration may play an important role in working memory.

A Knowledge Model System for Wheat Production Management

A knowledge model with temporal and spatial characteristics for the quantitative design of a cultural pattern in wheat production, using systems analysis and dynamic modeling techniques, was developed for wheat management, as a decision-making tool in digital farming. The fundamental relationships and algorithms of wheat growth indices and management criteria to cultivars, ecological environments, and production levels were derived from the existing literature and research data to establish a knowledge model system for quantitative wheat management using Visual C^＋＋. The system designed a cultural management plan for general management guidelines and crop regulation indices for timecourse control criteria during the wheat-growing period. The cultural management plan module included submodels to determine target grain yield and quality, cultivar choice, sowing date, population density, sowing rate, fertilization strategy, and water management, whereas the crop regulation indices module included submodels for suitable development stages, dynamic growth indices, source-sink indices, and nutrient indices. Ewluation of the knowledge model by design studies on the basis of data sets of different eco-sites, cultiwrs, and soil types indicated a favorable performance of the model system in recommending growth indices and management criteria under diverse conditions. Practical application of the knowledge model system in comparative field experiments produced yield gains of 2.4% to 16.5%. Thus, the presented knowledge model system overcame some of the difficulties of the traditional wheat management patterns and expert systems, and laid a foundation for facilitating the digitization of wheat management.

High-Speed Railway Train Timetable Conflict Prediction Based on Fuzzy Temporal Knowledge Reasoning

Trains are prone to delays and deviations from train operation plans during their operation because of internal or external disturbances. Delays may develop into operational conflicts between adjacent trains as a result of delay propagation, which may disturb the arrangement of the train operation plan and threaten the operational safety of trains. Therefore, reliable conflict prediction results can be valuable references for dispatchers in making more efficient train operation adjustments when conflicts occur. In contrast to the traditional approach to conflict prediction that involves introducing random disturbances, this study addresses the issue of the fuzzification of time intervals in a train timetable based on historical statistics and the modeling of a high-speed railway train timetable based on the concept of a timed Petri net. To measure conflict prediction results more comprehensively, we divided conflicts into potential conflicts and certain conflicts and defined the judgment conditions for both. Two evaluation indexes, one for the deviation of a single train and one for the possibility of conflicts between adjacent train operations, were developed using a formalized computation method. Based on the temporal fuzzy reasoning method, with some adjustment, a new conflict prediction method is proposed, and the results of a simulation example for two scenarios are presented. The results prove that conflict prediction after fuzzy processing of the time intervals of a train timetable is more reliable and practical and can provide helpful information for use in train operation adjustment, train timetable improvement, and other purposes.

Narrating the Past in Different Contexts:C-BI Approach to the Present Perfect and Past Simple

Concept-based instruction(C-BI)has proven to be effective in improving students’command of grammar items used out of context by offering the students revision lessons,but its effect in teaching newly-introduced grammar items in a complex context of a specific genre remains unclear.To probe C-BI’s effect on students’use of the past simple and present perfect tenses out of context and in the context of a narrative by its description of the grammar concept in its materialization,that is,the Schemas of a Complete Orienting Basis of an Action(SCOBAs),we taught the two tenses to 40 eighth-graders in a Chinese middle school in our three-week teaching experiment.The qualitative and quantitative analysis of the results shows that i)in both out-ofcontext use and in-context use,accuracy of using the target tenses is higher after C-BI intervention;ii)by improving their conceptual knowledge through C-BI,the students are helped to pin down reference time and are hence more certain in using the target tenses.Moreover,they are encouraged to use the newly-introduced tenses in the complex context of the narrative genre;iii)both in simple contexts or complex contexts,the SCOBAs are effective in helping students navigate the learning task and determine their intended meaning by establishing temporal reference in the context.

Modeling of goethite iron precipitation process based on time-delay fuzzy gray cognitive network

The goethite iron precipitation process consists of several continuous reactors and involves a series of complex chemical reactions,such as oxidation reaction,hydrolysis reaction and neutralization reaction.It is hard to accurately establish a mathematical model of the process featured by strong nonlinearity,uncertainty and time-delay.A modeling method based on time-delay fuzzy gray cognitive network(T-FGCN)for the goethite iron precipitation process was proposed in this paper.On the basis of the process mechanism,experts’practical experience and historical data,the T-FGCN model of the goethite iron precipitation system was established and the weights were studied by using the nonlinear hebbian learning(NHL)algorithm with terminal constraints.By analyzing the system in uncertain environment of varying degrees,in the environment of high uncertainty,the T-FGCN can accurately simulate industrial systems with large time-delay and uncertainty and the simulated system can converge to steady state with zero gray scale or a small one.

Space-Time Correlation Based Fast Regional Spectrum Sensing in Cognitive Radio

In this paper,a space-time correlation based fast regional spectrum sensing(RSS)scheme is proposed to reduce the time and energy consumption of traditional spatial spectrum sensing. The target region is divided into small meshes,and all meshes are clustered into highly related groups using the spatial correlation among them. In each group,some representative meshes are selected as detecting meshes(DMs)using a multi-center mesh(MCM)clustering algorithm,while other meshes(EMs)are estimated according to their correlations with DMs and the Markov modeled dependence on history by MAP principle. Thus,detecting fewer meshes saves the sensing consumption. Since two independent estimation processes may provide contradictory results,minimum entropy principle is adopted to merge the results. Tested with data acquired by radio environment mapping measurement conducted in the downtown Beijing,our scheme is capable to reduce the consumption of traditional sensing method with acceptable sensing performance.

Time series online prediction algorithm based on least squares support vector machine

Deficiencies of applying the traditional least squares support vector machine （LS-SVM） to time series online prediction were specified. According to the kernel function matrix＇s property and using the recursive calculation of block matrix, a new time series online prediction algorithm based on improved LS-SVM was proposed. The historical training results were fully utilized and the computing speed of LS-SVM was enhanced. Then, the improved algorithm was applied to timc series online prediction. Based on the operational data provided by the Northwest Power Grid of China, the method was used in the transient stability prediction of electric power system. The results show that, compared with the calculation time of the traditional LS-SVM（75 1 600 ms）, that of the proposed method in different time windows is 40-60 ms, proposed method is above 0.8. So the improved method is online prediction. and the prediction accuracy（normalized root mean squared error） of the better than the traditional LS-SVM and more suitable for time series online prediction.

Control and its role in the process of ensuring knowledge continuity

With the commencement of the 21st century, the information age, knowledge economy and integration of information and knowledge among production factors, organizations show increasing interest in knowledge management. Managers are trying not only to preserve knowledge and transfer it efficiently within their organization, but also to ensure that it is not lost when a knowledge employee leaves the organization. Therefore, it is indispensable for organizations to monitor, record, transfer and preserve their knowledge. In order to ensure efficient preservation of knowledge by the organization, it is essential to integrate the area of the so-called knowledge continuity into the general management and ensure its maximum value. The goal of the article is to identify the role of control in the transformation process and its impact on ensuring knowledge continuity within the organization. A partial goal lies in identifying output quality control by means of productivity One of the conclusions of the article is that in today＇s economic situation, ignoring the existence of knowledge continuity could result in a crisis of management of knowledge and its loss.

Optimal Time and Bandwidth Allocation Based on Nash Bargaining Solution for Cooperative Cognitive Systems

In this paper,we propose a cooperative spectrum sharing strategy based on the Nash bargaining solution.Specifically,the primary system leases a fraction of its transmission time to the secondary system in exchange for cooperation to improve its transmission performance.To gain access to the spectrum of the primary system,the secondary system needs to split a fraction of its transmission bandwidth to help to forward the primary signal.As a reward,the secondary system can use the remaining bandwidth to transmit its own signal.We find a unique solution for this time and bandwidth allocation using the Nash bargaining solution.Simulation results demonstrate that the performance of the primary and secondary systems can both be improved by the proposed spectrum sharing strategy.

Acknowledgments to reviewers of World Journal of Gastroenterology

many reviewers have contributed their expertise and time to the peer review,a critical process to ensure the quality of World Jowrnal of Gastroenterology The editors and anthors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles （including those published in this issue and those rejected for this issue） during the last editing time period.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed their expertise and time to the peer review,a critrical process to ensure the quality of World Journal of Gastroenterology.The editors and authors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles （including those published in this issue and those rejected for this issue）during the last editing time period.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed their expertise and time to the peer review,a critical process to ensure the quality of World Journal of Gastroenterology .The editors and authors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles（including those published in this issue and those rejected for this issue）during hte last editing time period.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed their expertise and time to the peer review, a critical process to ensure the quality of World Journal of Gastroenterology. The editors and authors of the articles submitted to the joural are grateful to the following reviewers for evaluating the articles （including those published in this issue and those rejected for this issue）during the last editing time period.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed their expertise and time to the peer review, a critical process to ensure the quality of World Journal of Gastroenterology. The editors and authors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles（ including those published in this issue and those rejected for this issue） during the last editing time preriod.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed theix expertise and time to the peer review,a critical process to ensure the quality of World Journal of Gastraenterology.The editors and authors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles （ineluding those published in this issue and those rejected for this issue ）during the last editing time period.

Acknowledgments to reviewers of World Journal of Gastroenterology

Many reviewers have contributed their expertise and time to the peer review, a critical process to ensure the quality of World Journal of Gastroenterology. The editors and authors of the articles submitted to the journal are grateful to the following reviewers for evaluating the articles（ including those published in this issue and those rejected for this issue） during the last editing time preriod.