一种高效自适应的CICQ交换机数据包切分机制

为了有效处理CICQ(Combined Input Crosspoint Queued)交换机中的变长数据包,通常采用切分-重组(Segmentation and Reassembly,SAR)机制将变长包切分为定长信元进行交换。针对目前已有切分方法在不同网络流量下交换效率低、灵活性差的问题,设计了一种基于CICQ交换机的高效自适应数据包切分机制。新机制的主要思想是根据输入端的队列状态实时改变切片大小,并采用相邻数据包合并切分的方式进行切片,以自适应网络环境中的不同流量和数据包长度。仿真结果表明,提出的数据包切分机制较传统切分方法有显著优势,与已有方法中表现最好的变长多包切分相比,在不同的流量下能获得更优的时延性能和系统稳定性。

Distribution and mechanism of gently dipping fractures subjected to river incision: A case study from Nujiang River, China

Gently dipping fractures subjected to river incision are widely distributed on rock slopes.In this paper,a rock slope on the Nujiang River(China)is investigated to study the role of gently dipping fractures in the rock slopes evolution.Detailed field surveys indicate that gentle fractures are concentrated in four main zones.Moreover,the kinematics of the fracture system suggest that the genesis of these fractures can be synthesized into a progressive evolution model.This model indicates that the joints begin with the formation of an array of en echelon cracks that are subjected to continued crack elongation and shearing before ultimately approaching one another and interacting to form a complex joint system.Geomechanical analysis is performed to reveal the mechanisms of this genesis,and three main fracture patterns are identified based on the slope stress and are classified with respect to the slope evolution.Based on the detail field investigations and the evolutionary history of the river valley,we propose that intermittent incision by the river was the main factor contributing to the concentrated distribution of gently dipping joints.

Nuclear entry of active caspase-3 is facilitated by its p3-recognition-based specific cleavage activity

As a critical apoptosis executioner, caspase-3 becomes activated and then enters into the nucleus to exert its function. However, the molecular mechanism of this nuclear entry of active caspase-3 is still unknown. In this study, we revealed that easpase-3 harbors a crm-l-independent nuclear export signal （NES） in its small subunit. Using reversecaspase-3 as the study model, we found that the function of the NES in caspase-3 was not disturbed by the conformational changes during induced caspase-3 activation. Mutations disrupting the cleavage activity or p3-recognition site resulted in a defect in the nuclear entry of active caspase-3. We provide evidence that the p3-mediated specific cleavage activity of active caspase-3 abrogated the function of the NES. In conclusion, our results demonstrate that during caspase-3 activation, NES is constitutively present, p3-mediated specific cleavage activity abrogates the NES function in caspase-3, thus facilitating the nuclear entry of active caspase-3.

“Three-Grade Criteria” of Radical Resection for Primary Liver Cancer

OBJECTIVE The present study was designed to develop the “Three- Grade Criteria” for radical resection of primary liver cancer （PLC） and to evaluate its clinical significance. METHODS Criteria for radical resection of PLC were summed up to 3 grades based on criterion development. Grade Ⅰ： complete removal of all gross tumors with no residual tumor at the excision margin. Grade Ⅱ： on the basis of Grade Ⅰ, additional 4 requirements were added： （1） the tumor was not more than two in number; （2） no tumor thrombi in the main trunks or the primary branches of the portal vein, the common hepatic duct or its primary branches, the hepatic veins or the inferior vena cava; （3）no hilar lymph nodes metastases; （4）no extrahepatic metastases. Grade Ⅲ ： in addition to the above criteria, negative postoperative follow-up result including AFP dropping to a normal level （with positive AFP before surgery） within 2 months after operation, and no residual tumor upon diagnostic imaging.The clinical data from 354 patients with PLC who underwent hepatectomy were reviewed retrospectively. Based on the “Three-Grade Criteria” these patients were divided into 6 groups： Grade Ⅰ radical group, Grade Ⅰ palliative group, Grade Ⅱ radical group, Grade Ⅱ palliative group, Grade Ⅲ radical group, Grade Ⅲ palliative group. The survival rate of each group was calculated by the life-table method and the rates compared among the groups. RESULTS The survival rate of patients receiving radical treatment was better than those receiving palliative treatment （P〈0.01）. Survival improved as more criteria were applied. The 5-year survival rate of the patients in Grade Ⅰ, Ⅱ and Ⅲ who underwent radical resection was 43.2%, 51.2% and 64.4%, respectively （P〈0.01）. CONCLUSION The “Three-Grade Criteria” may be applied for judging the curability of resection therapy for PLC. The stricter the criterion used, the better the survival would be. Adopting high-grade criteria to select cases and guide operations and strengthening postoperative follow-up would improve the results of hepatectomy for PLC.

Evaluation and Optimization of the Mixed Redundancy Strategy in Cloud-Based Systems

Mixed redundancy strategies are generally used in cloud-based systems,with different node switch mechanisms from traditional fault-tolerant strategies.Existing studies often concentrate on optimizing a single strategy in cloud computing environment and ignore the impact of mixed redundancy strategies.Therefore,a model is proposed to evaluate and optimize the reliability and performance of cloud-based degraded systems subject to a mixed active and cold standby redundancy strategy.In this strategy,node switching is triggered by a continual monitoring and detection mechanism when active nodes fail.To evaluate the transient availability and the expected job completion rate of systems with such kind of strategy,a continuous-time Markov chain model is built on the state transition process and a numerical method is used to solve the model.To choose the optimal redundancy for the mixed strategy under system constraints,a greedy search algorithm is proposed after sensitivity analysis.Illustrative examples were presented to explain the process of calculating the transient probability of each system state and in turn,the availability and performance of the whole system.It was shown that the near-optimal redundancy solution could be obtained using the optimizationmethod.The comparison with optimization of the traditional mixed redundancy strategy proved that the system behavior was different using different kinds of mixed strategies and less redundancy was assigned for the new type of mixed strategy under the same system constraint.

Dynamic spectrum allocations in multi-cells and intra-cell of cognitive network to enhance system performance

In this study, we propose new dynamic spectrum allocations in multi-cells and intra-cell of cognitive network to enhance system performance in terms of decreasing probability of interruption and spectrum handoff of communication services in a cognitive system. The inter-cells of the spectrum allocation mechanism is designed to share the risk of vacating spectrum caused by licensed incumbents re-occupying the spectrum and minimize probability of service interruption in the cognitive network. This mechanism also can guarantee fairness among multi-cells. The intra-cell of the proposed spectrum allocation is based on a service data hierarchical model and establishes a mapping mechanism between layered data and the spectrum. It can reduce probability of spectrum handoff. Finally, simulation results are given and show that the new mechanism can reduce service interruption ratio and the probability of spectrum handoff caused by licensed incumbents with re-occupying the spectrum.

Reversible switching between normal and thermally activated delayed fluorescence towards “smart” and single compound whitelight luminescence via controllable conformational distribution

An organic compound exhibiting simultaneously reversible switch between its emission colors and luminescence mechanisms,possessing high contrast from deep blue normal fluorescence(NF) to yellow thermally activated delayed fluorescence(TADF),is reported. Based on these two complementary colors, white-light emission combining NF and TADF from a single compound can be achieved in various states. Experimental results and density functional theory calculations indicate that the controllable conformational distribution under thermal and mechanical activation is the mechanism responsible for the reversible switching behavior.