A two-tier location management mechanism for IMS

This paper proposed a two-tier location management mechanism （TTLM） by improving the current registration mechanism （CR） in IP Multimedia Subsystem （IMS）. The TTLM includes the visited network registration and the home network registration, in which the visited network registration is responsible for re-registration in IMS. When subscriber roams, the location information of home network will be updated by the visited network based on the change of user equipment （UE）＇ s IP address. Thereibre the TTLM can reduce the times of IMS registration signaling. Using the proposed analytical model, the performance of the CR and the proposed TTLM were investigated. After the performance analysis of CR and TTLM by using proposed analytical model, the cost of CR in IMS could significantly be reduced theoretically and also was proven by simulation experiments.

Two-tier control structure design methodology applied to heat exchanger networks

Because of its paramount importance in the successful industrial control strategy of a given heat exchanger network(HEN),the control structure designs for providing appropriate manipulated variable(MV)and controlled variable pairings have received considerable attention.However,quite frequently HENs with such control structures face the problem of hard constraints,typically holding the HENs at less controlled operating space.So both the MV pairings and the above control pairings should be considered to design a control structure.This paper investigates the systematic incorporation of the two pairings,and presents a methodology for designing such two-tier control structure.This is developed based on the sequential strategy,coupling an indirect-tier with direct-tier control structure design,wherein the intention is realized in the former stage and the latter is implemented for further optimization.The MV identification and pairing are achieved through variations in heat load of heat exchangers to design the indirect-tier control structure.Then the direct-tier control structure is followed the relative gain array pairing rules.With the proposed methodology,on the one hand,it generates an explicit connection between the MV pairings and the HEN configuration,and the quantitative interaction measure is improved to avoid the multiple solutions to break the relationship among all the control pairings into individuals;on the other hand,a two-tier control structure reveals control potentials and control system design requirements,this may avoid complex and economically unfavourable control and HEN structures.The application of proposed framework is illustrated with two cases involving the dynamic simulation analysis,the quantitative assessment and the random test.

INTERFERENCE COORDINATION METHOD BASED ON GRAPH THEORY IN TWO-TIER CELLULAR NETWORKS

This paper studies an interference coordination method by means of spectrum allocation in Long-Term Evolution (LTE) multi-cell scenario that comprises of macrocells and femtocells. The purpose is to maximize the total throughput of femtocells while ensuring the Signal-to-Interference plus Noise Ratio (SINR) of the edge macro mobile stations (mMSs) and the edge femtocell Mobile Stations (fMSs). A new spectrum allocation algorithm based on graph theory is proposed to reduce the interference. Firstly, the ratio of Resource Blocks (RBs) that mMSs occupy is obtained by genetic algorithm. Then, after considering the impact of the macro Base Stations (mBSs) and small scale fading to the fMS on different RBs, multi-interference graphs are established and the spectrum is allocated dynamically. The simulation results show that the proposed algorithm can meet the Quality of Service (QoS) requirements of the mMSs. It can strike a balance between the edge fMSs' throughput and the whole fMSs' throughput.

Distributed robust power control in two-tier vehicle networks under uncertain channel environments

This paper proposes a novel optimization scheme to support stable and reliable vehicle-to-everything connections in two-tier networks,where the uplink channel of the cellular user is reused by underlay vehicle-to-vehicle communications.However,considering complex channel fading and high-speed vehicle movement,the cer-tainty assumption is impractical and fails to maintain power control strategy in reality in the traditional statical vehicular networks.Rather than the perfect channel state information assumption,the first-order Gauss-Markov process which is a probabilistic model affected by vehicle speed and fading is introduced to describe imperfect channel gains.Moreover,interference management is a major challenge in reusing communications,especially in uncertain channel environments.Power control is an effective way to realize interference management,and optimal power allocation can ensure that interference of the user meets the communication requirements.In this study,the sum-rate-oriented power control scheme and minimum-rate-oriented power control scheme were implemented to manage interference and satisfy different design objectives.Since both of these schemes are non-convex and intractable,the Bernstein approximation and successive convex approximation methods were adopted to transform the original problems into convex ones.Furthermore,a novel distributed robust power control al-gorithm was developed to determine the optimal solutions.The performance of the algorithm was evaluated through numerical simulations,and the results indicate that the proposed algorithm is effective in vehicular communication networks with uncertain channel environments.

A New Handover Management Model for Two-Tier 5G Mobile Networks

There has been an exponential rise in mobile data traffic in recent times due to the increasing popularity of portable devices like tablets,smartphones,and laptops.The rapid rise in the use of these portable devices has put extreme stress on the network service providers while forcing telecommunication engineers to look for innovative solutions to meet the increased demand.One solution to the problem is the emergence of fifth-generation(5G)wireless communication,which can address the challenges by offering very broad wireless area capacity and potential cut-power consumption.The application of small cells is the fundamental mechanism for the 5Gtechnology.The use of small cells can enhance the facility for higher capacity and reuse.However,it must be noted that small cells deployment will lead to frequent handovers of mobile nodes.Considering the importance of small cells in 5G,this paper aims to examine a new resource management scheme that can work to minimize the rate of handovers formobile phones through careful resources allocation in a two-tier network.Therefore,the resource management problem has been formulated as an optimization issue thatwe aim to overcome through an optimal solution.To find a solution to the existing problem of frequent handovers,a heuristic approach has been used.This solution is then evaluated and validated through simulation and testing,during which the performance was noted to improve by 12%in the context of handover costs.Therefore,this model has been observed to be more efficient as compared to the existing model.

An efficient and DoS-resistant user authentication scheme for two-tiered wireless sensor networks

Wireless sensor networks (WSNs) are vulnerable to security attacks due to their deployment and resource constraints.Considering that most large-scale WSNs follow a two-tiered architecture,we propose an efficient and denial-of-service (DoS)-resistant user authentication scheme for two-tiered WSNs.The proposed approach reduces the computational load,since it performs only simple operations,such as exclusive-OR and a one-way hash function.This feature is more suitable for the resource-limited sensor nodes and mobile devices.And it is unnecessary for master nodes to forward login request messages to the base station,or maintain a long user list.In addition,pseudonym identity is introduced to preserve user anonymity.Through clever design,our proposed scheme can prevent smart card breaches.Finally,security and performance analysis demonstrates the effectiveness and robustness of the proposed scheme.

Three-Tier Knowledge Management System Based on .NET

Three-tier knowledge management system based on .NET architecture is designed according to requirement specification, characteristics of and relationship between enterprise electronic archives and knowledge management. This system using three-tier design based on factory pattern has good encapsulation and portability, with clearer and more concise structure. It degrades the costs of system development and maintenance and upgrades system’s high reusability and development efficiency.

Optimal operation of Internet Data Center with PV and energy storage type of UPS clusters

With the development of green data centers,a large number of Uninterruptible Power Supply(UPS)resources in Internet Data Center(IDC)are becoming idle assets owing to their low utilization rate.The revitalization of these idle UPS resources is an urgent problem that must be addressed.Based on the energy storage type of the UPS(EUPS)and using renewable sources,a solution for IDCs is proposed in this study.Subsequently,an EUPS cluster classification method based on the concept of shared mechanism niche(CSMN)was proposed to effectively solve the EUPS control problem.Accordingly,the classified EUPS aggregation unit was used to determine the optimal operation of the IDC.An IDC cost minimization optimization model was established,and the Quantum Particle Swarm Optimization(QPSO)algorithm was adopted.Finally,the economy and effectiveness of the three-tier optimization framework and model were verified through three case studies.

基于Delphi的C/S结构数据库应用程序的开发

Delphi是当今数据库应用软件开发的主流工具。基于Delphi的Two-Tier结构的C/S开发模式,介绍了用Delphi开发C/S数据库应用程序的方法,并通过实例,描述了从ADO数据库程序设计标准、数据库控件的使用及荐储过程的编写直到Delphi数据库应用程序实现的整个开发过程。

两层和三层Client/Server结构的分析

介绍两层和三层客户／服务器结构，分析它们各自的优缺点，以及对重用的难易程度和开发阶段进行了比较，以便对给定项目进行结构的适当选择。

IRT框架下追踪数据的测量不变性分析--以4至5岁儿童认知能力测验为例

本研究以4岁~5岁儿童认知能力测验为例,在IRT框架下探讨了如何进行追踪数据的测量不变性分析。分析模型采用项目间多维项目反应理论模型（between-item MIRT model）和项目内（within-item MIRT model）多维two-tier model,被试为来自全国的882名48个月的儿童,工具为自编4岁~5岁儿童认知能力测验。经测验水平分析和项目水平分析,结果表明：（1）本文对追踪数据的测量不变性分析方法合理有效;（2）该测验在两个时间点上满足部分测量不变性要求,测验的潜在结构稳定;（3）＂方位题＂的区分度和难度参数都发生变化,另有4题难度参数出现浮动;（4）儿童在4岁~5岁期间认知能力总体呈快速发展趋势,能力增长显著。

多维题组反应模型:多维随机系数多项Logistic模型的应用拓展

本文将多维随机系数多项Logistic模型(MRCMLM)拓展应用到多维题组领域,得到适用于多维目标能力和多维题组效应的多维题组反应模型(MTRM),该模型具有高度灵活性和适用性。本文通过两个模拟研究和一个应用研究探究MTRM参数估计精度和模型适用性,以及与two-tier模型的差异,结果发现:(1)能力维度间相关和项目评分等级是影响模型参数估计的重要因素;(2)MTRM对项目参数估计准确性和稳定性高于two-tier模型,对题组效应大小估计更为准确。(3)MTRM在考虑项目内多维题组情况下模型拟合度更高,为测验分析提供了更广泛的模型结构选择,具有显著的应用价值。

Delphi三层结构在网上考试系统中的应用

主要描述了Delphi的三层结构和应用Delphi的三层结构开发基于局域网的网上考试系统,给出了三层数据库程序设计原理,详细阐述了网上考试系统的设计。

基于三层次客户机/服务器体系的优越性

通过将两层C/S模型结构与三层C/S模型结构在广域网上的应用比较,给出了两层结构模型在广域网应用的问题和困难,同时也给出了三层结构模型应用的优越性。

J2EE体系结构探讨

介绍了两层结构、三层结构、网络结构和J2EE体系结构在构建企业应用程序解决方案时各自的优缺点,并着重探讨了J2EE体系结构及在构建企业应用程序解决方案时的优点。

基于B/S三层结构的证券实时行情系统

在研究基于C/S二层结构的证券实时行情系统基础上,构建了一种简单可靠并遵循J2EE技术规范的B/S三层结构的证券实时行情系统。详细描述了实现系统的内部三层结构体系,并详细说明了采用Applet/Servlet、多线程技术实现系统的方案方法。

基于多层结构应用技术的研究

多层分布计算应用服务技术是目前数据库应用发展的潮流文章讨论传统客户／服务器（二层）的应用存在的局限性及三层结构所要解决的问题并对三层结构的优势及开发三层应用的工具加以论进

Expression of serum human epididymal secretory protein E4 at low grade and high grade serous carcinomas

Objective:To investigate the value of serum human epididymis protein 4(HE4) in differential diagnosis of patients with low-grade serous(LGSC) and high-grade serous carcinoma(HGSC) serous ovarian cancer.Methods:LGSC and HGSC serous ovarian cancer were diagnosed by the two-tier grade system,serum levels of HE4 and carbohydrate antigen 12S(CA125) were measured by ELBA and radioisotope method,respectively in 60 serous ovarian cancer patients. HE4 and TPS3 protein in cancer tissue were measured by immunohistochemical method. Results:The difference in density of HE4 and TP53 protein was significant between LGSC and HGSC tissue,while serum CA12S did not show significant difference between different serum samples.There was significant difference in serum HE4 levels between LGSC and HGSC and the result was different within FIGO(Ⅰ+Ⅱ) stage,suggesting HE4 was not a reliable biomarker for the discrimination between LGSC and HCSC.HE4 had potential as a biomarker for the discrimination between LGSC and HGSC but the role in early diagnosis was limited.Conclusions:HE4 may be a reliable marker for differential diagnosis of LGSC and HGSC.But its role in early diagnosis of LGSC and HGSC need to be confirmed from the perspective of two-tier grade system.

基于.net的三层架构B/S工作日志管理系统设计与实现

论述三层架构在软件开发中的应用的优缺点。采用asp.net实现基于B/S的三层架构的工作日志管理系统。

Multiple Mobile Sinks Data Dissemination Mechanism for Large Scale Wireless Sensor Network

WSN has been developing from traditional environment monitoring applications to the ubiquitous information services such as the Congestion-oriented Intelligent Transportation System （ColTS）. However, the mobility of nodes makes data dissemination a hard nut to crack. In this paper, we propose MSDD, a multiple mobile sinks data dissemination mechanism for solving the dissemination problem. The main ideas of MSDD are constructing a two-tier grid structure by a designated sink, exploiting a hierarchical monitoring mechanism, and employing a global agent to track the sink locations in order to make the emergencies reported to the sinks immediately, In addition, MSDD supports the query-driven data dissemination. Being compared with TTDD, MSDD is theoretically proved to have less communication overhead. We also validate MSDD outperforms TTDD in reliability and the emergency delivery latency bv simulations.