Mobile Edge Computing Servers Deployment with Improved Genetic Algorithm in Cellular Internet of Things

Mobile edge computing(MEC)provides services to devices and reduces latency in cellular internet of things(IoT)networks.However,the challenging problem is how to deploy MEC servers economically and efficiently.This paper investigates the deployment problem of MEC servers of the real-world road network by employing an improved genetic algorithm(GA)scheme.We first use the threshold-based K-means algorithm to form vehicle clusters according to their locations.We then select base stations(BSs)based on clustering center coordinates as the deployment locations set for potential MEC servers.We further select BSs using a combined simulated annealing(SA)algorithm and GA to minimize the deployment cost.The simulation results show that the improved GA deploys MEC servers effectively.In addition,the proposed algorithm outperforms GA and SA algorithms in terms of convergence speed and solution quality.

Adaptive Load Balancing for Parameter Servers in Distributed Machine Learning over Heterogeneous Networks

In distributed machine learning(DML)based on the parameter server(PS)architecture,unbalanced communication load distribution of PSs will lead to a significant slowdown of model synchronization in heterogeneous networks due to low utilization of bandwidth.To address this problem,a network-aware adaptive PS load distribution scheme is proposed,which accelerates model synchronization by proactively adjusting the communication load on PSs according to network states.We evaluate the proposed scheme on MXNet,known as a realworld distributed training platform,and results show that our scheme achieves up to 2.68 times speed-up of model training in the dynamic and heterogeneous network environment.

An Efficient Framework for Utilizing Underloaded Servers in Compute Cloud

In cloud data centers,the consolidation of workload is one of the phases during which the available hosts are allocated tasks.This phenomenon ensures that the least possible number of hosts is used without compromise in meeting the Service Level Agreement(SLA).To consolidate the workloads,the hosts are segregated into three categories:normal hosts,under-loaded hosts,and over-loaded hosts based on their utilization.It is to be noted that the identification of an extensively used host or underloaded host is challenging to accomplish.Thresh-old values were proposed in the literature to detect this scenario.The current study aims to improve the existing methods that choose the underloaded hosts,get rid of Virtual Machines(VMs)from them,andfinally place them in some other hosts.The researcher proposes a Host Resource Utilization Aware(HRUAA)Algorithm to detect those underloaded and place its virtual machines on different hosts in a vibrant Cloud environment.The mechanism presented in this study is contrasted with existing mechanisms empirically.The results attained from the study estab-lish that numerous hosts can be shut down,while at the same time,the user's workload requirement can also be met.The proposed method is energy-efficient in workload consolidation,saves cost and time,and leverages active hosts.

Graph Partitioning Method to Determine Servers Placement in CDN

To determine CDN cache servers'placement reasonably,an idea that using graph partitioning to solve the problem was put forward through theoretical analysis and the specific algorithm of partitioning was researched. The concept of graph partitioning for CDN was defined. The conditions of graph partitioning for CDN were demonstrated: the sum of the weights of the nodes in each subarea is as close as possible; edge cut between the subareas is as large as possible; internal nodes in each subarea are connected as far as possible. By reference to light vertex matching algorithm of graph partitioning for network simulation,a multilevel k-way algorithm of graph partitioning for CDN was proposed. The maximized edge cut k-way KL refinement algorithm was discussed. Graph partitioning is a feasible way to solve the problem of CDN servers'placement. Multilevel k-way algorithm is a feasible algorithm for CDN graph partitioning.

The Configuration Strategies on Caching for Web Servers

The Web cluster has been a popular solution of network server system because of its scalability and cost effective ness. The cache configured in servers can result in increasing significantly performance, In this paper, we discuss the suitable configuration strategies for caching dynamic content by our experimental results. Considering the system itself can provide support for caching static Web page, such as computer memory cache and disk＇s own cache, we adopt a special pattern that only caches dynamic Web page in some experiments to enlarge cache space. The paper is introduced three different replacement algorithms in our cache proxy module to test the practical effects of caching dynamic pages under different conditions. The paper is chiefly analyzed the influences of generated time and accessed frequency on caching dynamic Web pages. The paper is also provided the detailed experiment results and main conclusions in the paper.

On One Model of Multichannel Queuing System with Unreliable Repairable Servers and Input Memory

The work deals with the development of analytical model of multichannel technical queuing system with unreliable servers and input memory where server failure flows and incoming request flows comply with Poissonian laws, while the flows of failed facilities repairs and flows of incoming requests comply with exponential laws of probability distribution. Random process of system change-over is a Markovian process with continuous time and discrete states. Relations binding basic parameters and output characteristics of the system indicated are obtained as probabilities of system staying in the given moment in one of the possible states. The proposed model is the most generalized compared to some models known in literature which could be considered as special cases of the considered model.

利用Delphi中Servers组件结合Word模板实现某些特殊功能的打印需求(一)

一、引言 在实际工作中,用户常常会提出某些特殊打印需求,比如各种证件、证明文件以及带有统计功能的数据库报表等等.

利用Dephi中Servers组件结合Word模板实现某些特殊打印报表需求(二)

一、引言 现实生活当中数据库的打印需求是相当多的,各种形式的打印报表都有,笔者不可能对这些报表一一列举并写出源代码,所以举这个例子是希望能起到抛砖引玉的作用,只要读者用心去体会其中的语句,一定会有所收获!

Rehabilitative Environment for Prison Servers

A prison can be something different as ordinary people imagine. It can be a therapeutic and rehabilitative environment, a place where human beings can learn to cope with the stressful situations they could not deal with in their past. That is what happens in the Rencheng prison under the administration of Lineng Prison Sub-Bureau of East China’s Shandong Province.

Active Authentication Protocol for IoV Environment with Distributed Servers

The Internet of Vehicles(IoV)has evolved as an advancement over the conventional Vehicular Ad-hoc Networks(VANETs)in pursuing a more optimal intelligent transportation system that can provide various intelligent solutions and enable a variety of applications for vehicular traffic.Massive volumes of data are produced and communicated wirelessly among the different relayed entities in these vehicular networks,which might entice adversaries and endanger the system with a wide range of security attacks.To ensure the security of such a sensitive network,we proposed a distributed authentication mechanism for IoV based on blockchain technology as a distributed ledger with an ouroboros algorithm.Using timestamp and challenge-responsemechanisms,the proposed authentication model can withstand several security attacks such asMan-in-Middle(MiM)attacks,Distributed Denial of Service(DDoS)attacks,server spoofing attacks and more.The proposed method also provides a solution for single-point failure,forward secrecy,revocability,etc.We exhibit the security of our proposed model by using formal(mathematical)analysis and informal analysis.We used Random Oracle Model to perform themathematical analysis.In addition,we compared the communication cost,computation cost,and security of the proposed model with the related existing studies.We have verified the security of the model by using AVISPA tool simulation.The security analysis and computation analysis show that the proposed protocol is viable.

Do ICMP Security Attacks Have Same Impact on Servers?

There are different types of Cyber Security Attacks that are based on ICMP protocols. Many ICMP protocols are very similar, which may lead security managers to think they may have same impact on victim computer systems or servers. In this paper, we investigate impact of different ICMP based security attacks on two popular server systems namely Microsoft’s Windows Server and Apple’s Mac Server OS running on same hardware platform, and compare their performance under different types of ICMP based security attacks.

基于ESP8266的单片机无线烧写器的设计与实现

为了简化51单片机烧写流程,克服传统单片机有线烧写的弊端,设计了基于ESP8266的单片机无线烧写器。该无线烧写器以ESP8266作为主控单元,通过Wi-Fi网络使用TCP协议与PC上的TCP服务器进行通信,获取烧写BIN文件,然后通过ESP8266内的烧写控制程序,适时对51单片机的电源进行控制,实现51单片机程序的自动烧写。测试结果验证了该设计方案的正确性和可用性。

SQL Server性能优化的技术分析

随着客户端/服务器技术和多层架构的进步,系统效率问题日益引发广泛讨论。由于缺乏数据库管理系统(DBMS)提供的优化方法和工具,以及基于微软技术的数据库管理员和应用程序开发人员的知识,无法对设计和服务执行系统进行优化。文章回顾了提高SQL Server实例性能时需要考虑的目标,并阐述了用于优化查询的技术。

Blockchain-Based Certificateless Bidirectional Authenticated Searchable Encryption Scheme in Cloud Email System

Traditional email systems can only achieve one-way communication,which means only the receiver is allowed to search for emails on the email server.In this paper,we propose a blockchain-based certificateless bidirectional authenticated searchable encryption model for a cloud email system named certificateless authenticated bidirectional searchable encryption(CL-BSE)by combining the storage function of cloud server with the communication function of email server.In the new model,not only can the data receiver search for the relevant content by generating its own trapdoor,but the data owner also can retrieve the content in the same way.Meanwhile,there are dual authentication functions in our model.First,during encryption,the data owner uses the private key to authenticate their identity,ensuring that only legal owner can generate the keyword ciphertext.Second,the blockchain verifies the data owner’s identity by the received ciphertext,allowing only authorized members to store their data in the server and avoiding unnecessary storage space consumption.We obtain a formal definition of CL-BSE and formulate a specific scheme from the new system model.Then the security of the scheme is analyzed based on the formalized security model.The results demonstrate that the scheme achieves multikeyword ciphertext indistinguishability andmulti-keyword trapdoor privacy against any adversary simultaneously.In addition,performance evaluation shows that the new scheme has higher computational and communication efficiency by comparing it with some existing ones.

基于VB 6.0的病案首页数据质量控制系统的实现与应用

目的基于VB 6.0编程设计软件开发病案首页数据质量控制系统,提高病案首页数据质量。方法通过调用SQL Server数据库中省规则、字典规则、数据逻辑规则和院内规则4个存储过程的方式构建病案首页数据质量控制系统。结果该系统实施应用后,根据首页数据质量评估系统每月评分反馈,2019年10月至2022年7月触犯校验规则为月均3.29例次,2022年8月至2023年8月降低至月均0.23例次;病案首页质量满分率由17.65%提升至84.62%,提升明显;病案质量满分率和校验规则满分率分别达100.00%、84.62%,有显著提升。结论目前大部分医院病案首页质量受医院信息化水平不高、医生相关病案知识匮乏、医院信息和病案工作人员的协作关系不佳等多方面制约,可通过应用该系统,帮助医院病案工作人员提高病案首页数据质量。

DRPS:efficient disk-resident parameter servers for distributed machine learning

Parameter server(PS)as the state-of-the-art distributed framework for large-scale iterative machine learning tasks has been extensively studied.However,existing PS-based systems often depend on memory implementations.With memory constraints,machine learning(ML)developers cannot train large-scale ML models in their rather small local clusters.Moreover,renting large-scale cloud servers is always economically infeasible for research teams and small companies.In this paper,we propose a disk-resident parameter server system named DRPS,which reduces the hardware requirement of large-scale machine learning tasks by storing high dimensional models on disk.To further improve the performance of DRPS,we build an efficient index structure for parameters to reduce the disk I/O cost.Based on this index structure,we propose a novel multi-objective partitioning algorithm for the parameters.Finally,a flexible workerselection parallel model of computation(WSP)is proposed to strike a right balance between the problem of inconsistent parameter versions(staleness)and that of inconsistent execution progresses(straggler).Extensive experiments on many typical machine learning applications with real and synthetic datasets validate the effectiveness of DRPS.

Python Server Page Performance Analysis and Modeling

Today, in the field of computer networks, new services have been developed on the Internet or intranets, including the mail server, database management, sounds, videos and the web server itself Apache. The number of solutions for this server is therefore growing continuously, these services are becoming more and more complex and expensive, without being able to fulfill the needs of the users. The absence of benchmarks for websites with dynamic content is the major obstacle to research in this area. These users place high demands on the speed of access to information on the Internet. This is why the performance of the web server is critically important. Several factors influence performance, such as server execution speed, network saturation on the internet or intranet, increased response time, and throughputs. By measuring these factors, we propose a performance evaluation strategy for servers that allows us to determine the actual performance of different servers in terms of user satisfaction. Furthermore, we identified performance characteristics such as throughput, resource utilization, and response time of a system through measurement and modeling by simulation. Finally, we present a simple queue model of an Apache web server, which reasonably represents the behavior of a saturated web server using the Simulink model in Matlab (Matrix Laboratory) and also incorporates sporadic incoming traffic. We obtain server performance metrics such as average response time and throughput through simulations. Compared to other models, our model is conceptually straightforward. The model has been validated through measurements and simulations during the tests that we conducted.

图书馆智慧化阅读推广建设研究

本研究旨在探讨以SQLServer为基础的图书馆阅读推广智慧化建设。通过对图书馆阅读推广数字服务系统的分析和研究,发现基于SQLServer的系统在运行过程中具有最短的响应时间,并且在多次测试中质量因子始终高于其他系统。此外,该系统还对阅读推广数据进行了预处理,提高了阅读推广的服务质量。本研究的结果对于图书馆阅读推广智慧化建设具有重要的参考价值。

基于WebGIS的测绘与地理信息服务模式研究

伴随GIS技术迅速进步并且互联网普及,Web GIS在测绘及地理信息服务上的优越性越来越明显。此项研究以Web GIS作为平台,对测绘与地理信息服务模式展开探讨。借助Web GIS工具,使用ArcGIS Server和iBroker技术构筑服务平台,设定并施行一种测绘与地理信息服务模式。研究成果揭示,这种以Web GIS为基础的服务模式不仅增强了测绘的效率,同时也大幅度提升了地理信息服务的便利性和易接入性。对于满足社会公众和专业人员的地理信息需求,改善地理信息服务的质量和效率具有重要的现实意义。同时,本研究还在模式设计中考虑了安全性和稳定性等因素,使得服务在应对大规模数据处理和并发请求时,能够保持稳定和高效运行。

存储过程和触发器在商超管理系统中的应用

存储过程和触发器是数据库中的重要编程对象,在系统设计中可以提升数据库的性能。触发器是一种特殊的存储过程,主要用于实现比约束更复杂的功能,维护数据的完整性。文章利用SQL Server 2019数据库管理工具,以商超管理系统为例,研究存储过程和触发器在该系统中的应用,并结合实际案例,给出了存储过程和触发器在解决具体业务问题中的实现方法。