“仿拟”论略

仿拟分为仿词、仿句和仿篇。在现阶段，仿拟不仅增添了访体这一新类型，而且又增加了造词这一新功能。由于具有造词功能，因而仿拟辞格在当前的语言生活中十分受欢迎。仿词的普遍使用就是最好的佐证。

Novel scheme to specify and integrate RBAC policy based on ontology

To describe and integrate various policies applied in different domains, the definition of the family of OntoRBAC based on the ontology of a general role-based access control （RBAC） policy is proposed, which can support and extend the RBAC96 model. The uniform ontology-based description mechanism of secure policies is applied in OntoRBAC, which can be used to describe different secure policies in distributed systems and integrate policies in semantic level with upper concepts. In addition, some rules have been defined to reason within the OntoRBAC to extend the inference algorithms in ontology, which makes the system accommodate itself to RBAC policies better.

Dynamic Polling MAC Scheme Considering Emergency Access in WSNs Based on Priorities

In Wireless Sensor Networks(WSNs),polling can obviously improve the throughput and decrease average access delay by allocating bandwidth efficiently and reasonably.In this paper,a Dynamic Polling Media Access Control (DPMAC) scheme designed according to WSNs' features is proposed.DPMAC is a priority based access control protocol with the characteristics that its polling table is dynamically refreshed depending on whether the sensor node is active and that the bandwidth is dynamically allocated according to the traffic types.The access priorities are determined by the emergency levels of events and the scheduler proposed in our MAC is preemptive based on the deadline of the events.Simulation results show that DPMAC can efficiently utilize bandwidth and decrease average access delay and response time for emergency events with different access priorities in WSNs.

Traffic-Aware Channelization Medium Access Control for Wireless Ad Hoc Networks

Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grai-ned manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks.

Role based access control design using Triadic concept analysis

Role based access control is one of the widely used access control models.There are investigations in the literature that use knowledge representation mechanisms such as formal concept analysis(FCA),description logics,and Ontology for representing access control mechanism.However,while using FCA,investigations reported in the literature so far work on the logic that transforms the three dimensional access control matrix into dyadic formal contexts.This transformation is mainly to derive the formal concepts,lattice structure and implications to represent role hierarchy and constraints of RBAC.In this work,we propose a methodology that models RBAC using triadic FCA without transforming the triadic access control matrix into dyadic formal contexts.Our discussion is on two lines of inquiry.We present how triadic FCA can provide a suitable representation of RBAC policy and we demonstrate how this representation follows role hierarchy and constraints of RBAC on sample healthcare network available in the literature.

Self-Organization Approaches for Optimization in Cognitive Radio Networks

Cognitive radio(CR) is regarded as a promising technology for providing a high spectral efficiency to mobile users by using heterogeneous wireless network architectures and dynamic spectrum access techniques.However,cognitive radio networks(CRNs)may also impose some challenges due to the ever increasing complexity of network architecture,the increasing complexity with configuration and management of large-scale networks,fluctuating nature of the available spectrum,diverse Quality-of-Service(QoS)requirements of various applications,and the intensifying difficulties of centralized control,etc.Spectrum management functions with self-organization features can be used to address these challenges and realize this new network paradigm.In this paper,fundamentals of CR,including spectrum sensing,spectrum management,spectrum mobility and spectrum sharing,have been surveyed,with their paradigms of self-organization being emphasized.Variant aspects of selforganization paradigms in CRNs,including critical functionalities of Media Access Control(MAC)- and network-layer operations,are surveyed and compared.Furthermore,new directions and open problems in CRNs are also identified in this survey.

Hierarchical Code Assignment Algorithm and StateBased CDMA Protocol for UWSN

The characteristics of underwater acoustic channel such as long propagation delay and low bit rate cause the MAC(Medium Access Control) protocols designed for radio channels to be either inapplicable,or have low efficiency for UWSN(Underwater Sensor Network).We propose a hierarchical and distributed code assignment algorithm based on divisive probability function which can avoid conflict between spread codes with high probability,and provide a statebased MAC protocol for UWSN.Without RTS/CTS(Request To Send/Clear To Send) handshaking,each node maintains a neighbor table including state field,and packages are forwarded according to the state of the receiver,so it can avoid the interference caused by transmitting to a sending node in a half-duplex system and improve channel utilization.The design of power control minimizes the nearfar effect inherent in CDMA.Simulation results reveal that state-based CDMA protocol shows outstanding performance in throughput,delivery ratio and resource-consumption.

Performance Analysis of WLAN Medium Access Control Protocols in Simulcast Radio-Over-Fiber-Based Distributed Antenna Systems

The performance of three wireless local-area network(WLAN) media access control(MAC) protocols is investigated and compared in the context of simulcast radioover-fiber-based distributed antenna systems(RoF-DASs) where multiple remote antenna units(RAUs) are connected to one access point(AP) with different-length fiber links.The three WLAN MAC protocols under investigation are distributed coordination function(DCF) in basic access mode,DCF in request/clear to send(RTS/CTS) exchange mode,and point coordination function(PCF).In the analysis,the inter-RAU hidden nodes problems and fiber-length difference effect are both taken into account.Results show that adaptive PCF mechanism has better throughput performances than the other two DCF modes,especially when the inserted fiber length is short.

Triple negative breast cancer: 5 years follow-up

Objective： The aim of the study was to investigate the long-term therapeutic effects of triple negative breast cancers （TNBCs） and find a standardized treatment. Methods： The clinical data and survival status of 69 patients with TNBC were collected, who were treated from 2003 to 2007 at Chongqing Cancer Institute, China. Results： Median observation for 61 months showed the local recurrence rate was 13.0% （9/69）, the overall survival （OS） rate was 76.8% （53/69） and the disease free survival （DFS） rate was 59.4% （41169）. Log-rank univariate survival analysis showed the OS and DFS rates of TNBCs with axillary lymph node metastasis were 38.1% and 23.8%, respectively, and the OS and DFS rates of triple negative breast cancer with axillary lymph node non-metastasis were 93.6% and 75.0%, respectively. There were significant differences comparing with two groups. Indictor analysis of age, menstruation status, tumor size, TNM stage, histological type, neoadjuvant chemotherapy and p53 did not show any prognostic influence. Conclusion： The axillary nodes metastasis is associated with DFS and OS in triple negative breast cancers. Cisplatin-based chemotherapy may be good choice for triple negative breast cancers with metastasis or local recurrence, who received Anthracycline and Taxane-based chemotherapy. Targeted therapies strategies such as EGFR-targeted therapy may be necessary.

Design and Evaluation of CRDMAC： Circular RTR Directional MAC Protocol for WANETs

Using directional antennas in Wireless Ad hoc Networks (WANETs) offers great potential of reducing the radio interference, and improving the communication throughput. Directional antennas, however, introduces new problems in the wireless Media Access Control (MAC), that is, the deafness and new hidden terminal problem, which may cause severe performance degradation. To solve the problems, we propose an effective Circular RTR Directional MAC (CRDMAC) protocol for WANETs by using a sub-transmission channel and Ready to Receive (RTR) packets, which modifies the IEEE 802.11 Distributed Coordinated Function (DCF). The sub-channel avoids collisions to other ongoing transmission, and the RTR packets notify the neighbor nodes that the mutual transmission has been finished. We evaluate the CRDMAC protocol through simulations and the results show that the proposed protocol outperforms existing DMAC (directional MAC) protocol and the CRCM (Circular RTS and CTS MAC) protocol in terms of throughput and packet drop rate.

A random adaptive method to adjust MAC parameters in IEEE802.11e WLAN

The IEEE 802.11e standard is proposed to provide QoS support in WLAN by providing prioritized differentiation of traffic. Since all the stations in the same priority access category (AC) have the same set of parameters, when the number of stations increases, the probability of different stations in the same AC choosing the same values will increase, which will result in collisions. Random adaptive MAC (medium access control) parameters scheme (RAMPS) is proposed, which uses random adaptive MAC differentiation parameters instead of the static ones used in the 802.11e standard. The performance of RAMPS is compared with that of enhanced distributed coordination access (EDCA) using NS2. The results show that RAMPS can reduce collision rate of the AC and improve the throughput by using adaptive random contention window size and inter-frame spacing values. RAMPS ensures that at any given time, several flows of the same priority have different MAC parameter values. By using the random offset for the inter-frame spacing value and the backoff time, RAMPS can provide intra-AC differentiation. The simulation results show that RAMPS outperforms EDCA in terms of both throughput and end-to-end delay irrespective of the traffic load.

Performance Analysis under MAC Layer Misbehavior Attack in Mobile Ad-Hoc Networks

This work presents a multi-criteria analysis of the MAC （media access control） layer misbehavior of the IEEE （Institute of Electrical and Electronics Engineers） 802.11 standard, whose principle is to cheat at the protocol to increase the transmission rate by greedy nodes at the expense of the other honest nodes. In fact, IEEE 802.11 forces nodes for access to the channel to wait for a back off interval, randomly selected from a specified range, before initiating a transmission. Greedy nodes may wait for smaller back-off intervals than honest nodes, and then obtaining an unfair assignment. In the first of our works a state of art on the research on IEEE 802.11 MAC layer misbehavior are presented. Then the impact of this misbehavior at the reception is given, and we will generalize this impact on a large scale. An analysis of the correlation between the throughput and the inter-packets time is given. Afterwards, we will define a new metric for measuring the performance and capability of the network.

Energy-efficient Medium Access Approach for Wireless Body Area Network Based on Body Posture

Energy efficiency has become one of the most important issues in wireless body area network(WBAN).In this paper,an energy-efficient medium access control(MAC)protocol for WBAN is proposed based on human body posture under walking scenery.Due to person's movements,WBAN is a dynamic network,which means that traditional static protocols are no more suitable for it.For solving this problem,firstly,the feature of human walking at a constant speed is analyzed and we divide a spell of movements into a sequence of key frames just like a video constituted by numbers of continuous frames.As a result,the dynamic walking process is translated into several static postures,which the static MAC protocol could be used for.Secondly,concerning the performance of network lifetime,we design a posture-aware approach for lifetime maximization(PA-DPLM).With analytical and simulation results provided,we demonstrate that PA-DPLM protocol is energy-efficient and can be used under constant speed walking scenery.

Physical activity,fitness and all-cause mortality:An 18-year follow-up among old people

Background：Little is known about change in physical activity（PA） and its relationship to all-cause mortality among old people.There is even less information about the association between PA,fitness and all-cause mortality among people aged 80 years and above.The objective is to investigate persistence and change in PA over 5 years as a predictor of all-cause mortality,and fitnes as a mediator of this association,among people aged 80 and 85 years at the beginning of an 18-year mortality follow-up period.Methods：Using Evergreen Project data（started in 1989）,4 study groups were formed according to self-reported changes in PA level,over a 5-year period（starting in 1989–1990 and ending in 1994–1995）：remained active（RA,control group）,changed to inactive（CI）,remained inactive（RI）,and changed to active（CA）.Mortality was followed up over the 18-year period（1994–2012）.Cox models with different covariates such as age,sex,use of alcohol,smoking,chronic diseases,and a 10 m walking test were used to analyze the association between change in PA level and mortality.Results：Compared to RA,those who decreased their PA level（CI） between baseline and follow-up had higher all-cause mortality（hazard ratio（HR=2.09;95%CI：1.63–2.69） when adjusted for age,gender,and chronic diseases.RI showed the highest all-cause mortality（HR = 2.16;95%CI：1.59–2.93）.In CA,when compared against RA,the risk of all-cause mortality was not statistically significan（HR=1.51;95%CI：0.95–2.38）.In comparison with RA,when walking speed over 10 m was added as a covariate,all-cause mortality risk was almost statistically significan only in CI（HR=1.37;95%CI：1.00–1.87）.Conclusion：Persistence and change in PA level was associated with mortality.This association was largely explained by fitnes status.Randomized controlled studies are needed to test whether maintaining or increasing PA level could lengthen the life of old people.

Architecture of Intra Prediction for High Efficiency Video Coding

This paper explains intra prediction method for High Efficiency Video Coding(HEVC).Intra prediction removes correlation of adjacent samples in spatial domain.Intra predictor requires reference images which are stored in external memory.Memory access is required frequently in process of intra prediction.The proposed architecture can reduce external memory access by optimized internal buffer.

Personalization on the TV on Demand

The Interactive Intemet TV Project is intended to be a web tool for publishing, indexing and viewing videos; that offers ontology based recommendations. The application has been developed and tested as a platform for e-learning in a univerasity context and in Optiva Media Company. It combines expertise in education and television to develop a prototype,., where the contents are generated using an automatic recommendation model based on personal profiles of each user; and that can be accessed from different devices： computers, mobile phones and so on.

Research on Architecture of Campus Mobile Library System based on Cloud Computing

Through analysis of cloud computing and characteristics, the paper described cloud computing infrastructure architecture. Mainly discusses cloud computing advantages in the use of the library and the use should pay attention to the problem, on this basis, we propose a cloud- based library information platform construction model to analyze the basic architecture of cloud computing, cloud-depth study calculated at the library information platform and database access patterns operating mode, and cloud computing future development and application prospects.

Dopamine receptor D2 polymorphism is associated with alleviation of obesity after 8-year follow-up: a retrospective cohort study in obese Chinese children and adolescents

Objective： The aim of this study was to explore the association of dopamine receptor D2 （DRD2） polymorphism and alleviation of obesity in children and adolescents after 8-year follow-up. Methods： This retrospective cohort study included obese children and adolescents with a follow-up period of 8 years. Baseline clinical character- istics and DRD2 polymorphisms （including rs1076562, rs2075654, and rs4586205） were extracted from medical records. A follow-up visit was performed in May 2017 to collect related data including height, weight, diet compliance, and exercise compliance. Results： One hundred and nine obese children and adolescents were included in the current study. Among three DRD2 single nucleotide polymorphisms, only rs2075654 had a statistically significant association with alleviation of obesity, as the alleviation rate for minor allele carders （68.6% for TC＋TT） was higher compared to the major allele homozygote （43.3% for CC）. After adjusting for all related factors, the hazard ratio of rs2075654 minor allele carders for the alleviation of obesity was 3.34 （95% confidence interval （CI）： 1.30-8.58）. Conclusions： The rs2075654 ~olvmomhism of DRD2 is related to Ionq-term obesity alleviation in obese Chinese children and adolescents.

Bariatric surgery proves long-term benefit in patients with cirrhosis

Background:Obesity is commonly observed in patients with cirrhosis,especially with the increasing prevalence of nonalcoholic steatohepatitis(NASH).Bariatric surgery has been avoided in these patients given concerns about increased perioperative risk;therefore,data are lacking regarding long-term outcomes.In this study,we aimed to evaluate the long-term outcomes of patients with cirrhosis who underwent bariatric surgery.Methods:We reviewed the charts of adult patients with compensated cirrhosis who underwent bariatric surgery after they were prospectively enrolled between February 23,2009 and November 9,2011,and followed in a pilot study for evaluation of bariatric surgery outcomes.Only patients with more than 4 years of follow-up were included in the analysis.Data regarding their liver disease,metabolic status,and survival were collected.A descriptive analysis was performed.Results:The cohort consisted of 10 patients,of whom 7 were females.The median post-surgical follow-up was 8.7 years(61.4 years).All patients had biopsy-proven NASH;two patients had concurrent,untreated hepatitis C infection.During the observation period,there was a mean weight loss of 24 kg(19.2%of total body weight pre surgery,P<0.001)and only one patient regained weight to the baseline pre-surgical measurement.One patient who was not eligible for transplant developed hepatic encephalopathy 3 years after surgery and later died.The remainder of the patients did not have any hepatic decompensation,cardiovascular event,or mortality.Except for one patient with Gilbert syndrome,bilirubin was normal in all patients at last follow-up.Conclusions:Bariatric surgery in patients with compensated cirrhosis can lead to sustained weight loss and stable hepatic function on long-termfollow-up.

In-home Power Line Communication Media Access Control Protocol Based on Collision Resolution

Most existing media access control(MAC) protocols in power line communication(PLC) networks just discard the colliding data packets when collision occurs.The collision deteriorates throughput and delay performance of system under high traffic conditions.This article presents a novel media access scheme with fast collision resolution for in-home power line networks.It works by first recognizing the colliding stations through detecting the inserted unique ID sequence ahead of data packets,then the source nodes retransmitting their packets immediately after the collision slot.The proposed protocol maintains the benefits of ALOHA systems.It needs no scheduling overhead and is suitable for bursty sources,such as multimedia data packets.Computer simulations have demonstrated that this approach can achieve high throughput due to its ability of resolving collisions.