This paper tries to solve the location-constrained virtual network embedding (LC-VNE) problem efficiently. We first investigate the complexity of LC-VNE, and by leveraging the graph bisection problem, we provide the first formal proof of the NP-completeness and inapproximability result of LC-VNE. Then, we propose two novel LC-VNE algorithms based on a compatibility graph (CG) to achieve integrated node and link mapping. In particular, in the CG, each node represents a candidate substrate path for a virtual link, and each link indicates the compatible relation between its two endnodes. Our theoretical analysis proves that the maximal clique in the CG is also the maximum one when the substrate network has sufficient resources. With CG, we reduce LC-VNE to the minimumcost maximum clique problem, which inspires us to propose two efficient LC-VNE heuristics. Extensive numerical simulations demonstrate that compared with the existing ones, our proposed LC-VNE algorithms have significantly reduced time complexity and can provide smaller gaps to the optimal solutions, lower blocking probabilities, and higher time-average revenue as well.

In this work, we study the availability-aware survivable virtual network embedding (A-SVNE) problem in optical interdatacenter networks that use wavelength-division multiplexing. With A-SVNE, we try to satisfy the availability requirement of each virtual component (i.e., a virtual link or a virtual node) in a virtual network. We first analyze the availability of a virtual component based on the availabilities of the substrate link(s) and node(s). Then, we formulate an integer linear programming model for the A-SVNE problem and propose several time-efficient heuristics. Specifically, we design two node mapping strategies: one is sequential selection using efficient weights defined by the availability information, while the other uses auxiliary graphs to transform the problem into a classical problem in graph theory, i.e., the maximum-weight maximum clique. Finally, we use extensive simulations to compare the proposed A-SVNE algorithms with existing ones in terms of the blocking probability, availability gap, and penalty due to service-level agreement violations, and the results indicate that our algorithms perform better.

Elastic optical networks (EONs) enable network operators to have agile bandwidth management in the optical layer. In this paper, we investigate dynamic and adaptive bandwidth defragmentation (DF) in EONs with time-varying traffic using connection reconfigurations. We consider how to design DF procedure in a systematic way, and study the problems that have not been fully explored so far. Basically, we divide the procedure design into four subproblems: How to reconfigure?, How to migrate traffic?, When to reconfigure?, and What to reconfigure?, and solve them sequentially. For How to reconfigure?, we investigate the combination of routing and spectrum assignment (RSA) algorithms for DF, i.e., the RSA algorithm that the connections are originally served with and the algorithm that they are re-optimized with. For How to migrate traffic?, we propose to construct a dependency graph to represent the relations among the selected connections and to use it to assist the best-effort traffic migration. A move-to-vacancy method is also proposed to further reduce the traffic disruptions. For When to reconfigure? and What to reconfigure?, we propose intelligent timing selection and adaptive DF ratio selection methods to tackle the tradeoff between the bandwidth blocking probability (BBP) performance and operational complexity. Simulation results show that the algorithm with both methods implemented (DF-AT-AR) achieves better tradeoff between BBP performance and operational complexity, when compared with existing algorithms.

With the development of datacenter networks and network virtualization, facility-failure-proof survivable virtual network embedding (SVNE) has recently gained notable attention. In this work, we design novel location-constrained SVNE (LC-SVNE) approaches that consider the working and backup embeddings jointly and protect virtual networks against single-facility-failures efficiently. We first transform the survivable node mapping to a bipartite graph matching problem and solve it for effective resource sharing among working and backup facilities. Then, two survivable link mapping schemes are designed to minimize the bandwidth consumption of virtual links, by leveraging anycast- and multicast-based substrate routing scenarios. Simulation results show that the proposed approaches outperform two existing ones on blocking probability and time-average revenue.

We propose intelligent timing and object selection algorithms for adaptive spectrum defragmentation in EONs with time-varying traffic. The simulation results show that the algorithms can stabilize and reduce bandwidth blocking probability (BBP) effectively with the minimum number of connection reconfigurations.

Studies estimating eye movements have demonstrated that non-human primates have fixation patterns similar to humans at the first sight of a picture. In the current study, three sets of pictures containing monkeys, humans or both were presented to rhesus monkeys and humans. The eye movements on these pictures by the two species were recorded using a Tobii eye-tracking system. We found that monkeys paid more attention to the head and body in pictures containing monkeys, whereas both monkeys and humans paid more attention to the head in pictures containing humans. The humans always concentrated on the eyes and head in all the pictures, indicating the social role of facial cues in society. Although humans paid more attention to the hands than monkeys, both monkeys and humans were interested in the hands and what was being done with them in the pictures. This may suggest the importance and necessity of hands for survival. Finally, monkeys scored lower in eye-tracking when fixating on the pictures, as if they were less interested in looking at the screen than humans. The locations of fixation in monkeys may provide insight into the role of eye movements in an evolutionary context.

To proceed from sensation to movement, integration and transformation of information from different senses and reference frames are required. Several brain areas are involved in this transformation process, but previous neuroanatomical and neurophysiological studies have implicated the caudal area 7b as one particular component of this transformation system. In this study, we present the first quantitative report on the spatial coding properties of caudal area 7b. The results showed that neurons in this area had intermediate component characteristics in the transformation system; the area contained bimodal neurons, and neurons in this area encode spatial information using a hybrid reference frame. These results provide evidence that caudal area 7b may belong to the reference frame transformation system, thus contributing to our general understanding of the transformation system.

Sleep/circadian timing depends on several neurotransmitter systems, including 5-HT, NE, DA, Ach, GABA, etc. These neurotransmitter systems play critical roles in mental, emotional and cognitive functions in the brain. Dysfunctions of these systems not only result in sleep disorder, but are also related to many psychiatric and neurodegenerative diseases. Sleep disruption is tightly associated with an increased susceptibility to a broad range of psychiatric and neurodegenerative diseases, such as depression and Parkinson diseases. Non-human primates, especially the rhesus monkey is an excellent biomedical model for human sleep and CNS diseases. Establishing nonhuman primates' model of mental disorders and monitoring the sleep changes during the development of the model will help us to know more about the relationships between sleep disorder and psychiatric and neurodegenerative diseases. Sleep disorder as an early marker for psychiatric and neurodegenerative diseases would permit early intervention of these diseases and draw attention to the potential therapeutic benefits of normalizing sleep rhythms in individuals with brain pathologies.

ABSTRACTIn rodents, a conditioned place preference (CPP) can be induced by morphine. In the current study, we designed a biased place conditioning paradigm to test the rewarding effects of morphine in freely moving rhesus monkeys. Five monkeys were first placed in three serial rooms with the doors open between them for three days. After this habituation period, during which baseline preference for each of the two end rooms was measured, CPP conditioning occurred when the monkeys were injected intramuscularly with morphine at an increasing dose (1.5, 3, 4.5 mg/kg) before they entered the non‐preferred room and on alternate days, with saline before they entered the preferred room. Morphine and saline treatment lasted for six days, respectively. CPP was tested 24 hours after the end of CPP training. The result showed that in all five monkeys, CPP was induced by the morphine treatment. The preference lasted for at least 15.3 ± 1.7 months.

Credit risk is not only the most important and oldest form of risk in the financial markets, but also the most decisive financial risk in the face of the economic subjects in the current market environment. It directly affects all aspects of modern economic, and also a country's macroeconomic policy-making and economic development, and it even affects the stability and coordination of the global economic. But in China, commercial banks with the flaws in their systems and their backward in management means are encountering serious credit risks. In this paper, through summarizing the credit of China's commercial banks and studying the root causes of these problems, some possible effective advices are put forward to resolve the credit risks of commercial banks.

Emotional stimuli have evolutionary significance for the survival of organisms; therefore, they are attention-grabbing and are processed preferentially. The neural underpinnings of two principle emotional dimensions in affective space, valence (degree of pleasantness) and arousal (intensity of evoked emotion), have been shown to be dissociable in the olfactory, gustatory and memory systems. However, the separable roles of valence and arousal in scene perception are poorly understood. In this study, we asked how these two emotional dimensions modulate overt visual attention. Twenty-two healthy volunteers freely viewed images from the International Affective Picture System (IAPS) that were graded for affective levels of valence and arousal (high, medium, and low). Subjects' heads were immobilized and eye movements were recorded by camera to track overt shifts of visual attention. Algebraic graph-based approaches were introduced to model scan paths as weighted undirected path graphs, generating global topology metrics that characterize the algebraic connectivity of scan paths. Our data suggest that human subjects show different scanning patterns to stimuli with different affective ratings. Valence salient stimuli (with neutral arousal) elicited faster and larger shifts of attention, while arousal salient stimuli (with neutral valence) elicited local scanning, dense attention allocation and deep processing. Furthermore, our model revealed that the modulatory effect of valence was linearly related to the valence level, whereas the relation between the modulatory effect and the level of arousal was nonlinear. Hence, visual attention seems to be modulated by mechanisms that are separate for valence and arousal.

UNLABELLED:The saccadic system has anatomical and functional connections with the pupillary light reflex (PLR) system. But it is not known whether the saccadic system modulates the PLR system. To investigate this issue, it is necessary to understand whether the uneven light stimulus to retina and the near responses influence the change of pupil diameter. We designed a new behavioral method to investigate the issue on human subjects.METHODS:one eye of the subject was stimulated by pulse light stimulus from a horizontal linear array of light emitting diodes (LEDs) presented across visual field in an ocular mask. The changes of the eye position and pupil diameter of another eye were recorded by an infrared eye tracking system.RESULTS:The relative constriction ratios of PLRs on the condition that the fixation points of subjects were in the nasal visual field were not significantly different from that the fixation points of subjects were in the temporal visual field(P=0.148, non-paired t test).CONCLUSION:The influences from uneven light stimulus to retina and the near responses were eliminated by this method. The method can be used to study the modulation from the saccadic system on the pupillary light reflex system.

The accurate implantation of microelectrodes is a significant difficulty facing many neurophysiologists. This paper reports on a new method used to promote the precise positioning of electrode implantation through magnetic resonance imaging (MRI), allowing both the relevant brain structure and the MRI-visible external markers anchored on the skull (in this case rigid glass tubes with a 0.5mm internal diameter) to be displayed. By referencing these markers, the coordinates of the brain target were calculated. Using this novel approach, recording electrodes were successfully implanted into the superior colliculus (SC) of rhesus monkeys, with an error <1mm, and its neuronal discharge signals were obtained. This new method allows neurophysiologists to precisely target the small deep brain structures of monkeys and study their electrophysiological characteristics in detail.

The responses of sensory neurons to repeated presentations of identical stimuli can be highly reproducible. Little is known about the reliability of the motor command signals carried by individual premotor neurons. We measured the variability in the interspike intervals of the high-frequency, saccade-related bursts generated by neurons in the pontine reticular formation. During movements having similar amplitudes and velocity profiles, the interspike intervals of the high-frequency component of the bursts are very similar. The low variability in interspike intervals cannot be attributed to a burst mode characterized by fixed interspike times. Different, but repeatable, burst patterns are observed when movements having approximately the same amplitude but different velocity profiles occur. These findings suggest that the discharge of a single pontine cell is strongly correlated with the activity of other pontine burst cells. Both the high temporal precision of the saccade-related bursts and the correlated activity of pontine burst cells reduce variability in the signals sent to the motoneuron pools and, thereby, contribute to the accuracy and precision of saccadic eye movements.