基于UML的文化中心设施管理系统的设计与实现

随着智慧城市的蓬勃发展,采用信息化手段辅助人们对基础设施进行管理势在必行。文中以天津市文化中心设施管理为基础,采用UML语言对文化中心设施管理系统进行分析设计,建立了系统的用例图、静态模型和动态模型,抽象出基础设施管理的共同特点,可提高系统开发的效率和重用性。最后,在分析设计的基础上进行了系统实现。     

我国商用密码管理现状与发展对策建议

随着信息技术日新月异的发展,网络环境日益复杂、安全形势瞬息万变,网络安全威胁的范围和内涵不断扩大和演化,我国面临的网络安全挑战日趋严峻。“没有网络安全就没有国家安全”,商用密码技术作为实现网络安全的核心技术,在网络安全防护工作中发挥着重要的基础支撑作用。聚焦我国商用密码管理现状,围绕政策法规、标准规范、技术实力、产业发展等内容进行研究,分析我国商用密码管理工作中的挑战,并提出相应的建议与举措,为商用密码管理工作提供了有益参考。     

SCM: Secure and accountable TLS certificate management

In classical public‐key infrastructure (PKI), the certificate authorities (CAs) are fully trusted, and the security of the PKI relies on the trustworthiness of the CAs. However, recent failures and compromises of CAs showed that if a CA is corrupted, fake certificates may be issued, and the security of clients will be at risk. As emerging solutions, blockchain‐ and log‐based PKI proposals potentially solved the shortcomings of the PKI, in particular, eliminating the weakest link security and providing a rapid remedy to CAs' problems. Nevertheless, log‐based PKIs are still exposed to split‐world attacks if the attacker is capable of presenting two distinct signed versions of the log to the targeted victim(s), while the blockchain‐based PKIs have scaling and high‐cost issues to be overcome. To address these problems, this paper presents a secure and accountable transport layer security (TLS) certificate management (SCM), which is a next‐generation PKI framework. It combines the two emerging architectures, introducing novel mechanisms, and makes CAs and log servers accountable to domain owners. In SCM, CA‐signed domain certificates are stored in log servers, while the management of CAs and log servers is handed over to a group of domain owners, which is conducted on the blockchain platform. Different from existing blockchain‐based PKI proposals, SCM decreases the storage cost of blockchain from several hundreds of GB to only hundreds of megabytes. Finally, we analyze the security and performance of SCM and compare SCM with previous blockchain‐ and log‐based PKI schemes.     

发达国家数字充电桩部署策略对我国的启示

当前我国亟需针对行业痛点,借鉴发达国家数字充电桩部署经验,强化顶层设计,明确建设需求,持续推进各级充电数据库的搭建和对接,深入挖掘充电信息服务平台价值,充分发挥地方政府和行业作用,完善全国综合充电网络,为用户提供高质量充电基础设施和智能灵活的充电解决方案。     

电信套餐资费配置研究

针对电信套餐资费人工配置周期长、效率低等现状,提出一种模板化的资费配置体系,采用预定义资费模板和自动化加载业务参数的方法,提升资费配置效率。针对集团级集约销售品进行了验证,并对套餐其他配置内容进行了扩展。     

470-MHz–698-MHz IEEE 802.15.4m Compliant RF CMOS Transceiver

This paper proposes an IEEE 802.15.4m compliant TV white-space orthogonal frequency-division multiplexing (TVWS)-(OFDM) radio frequency (RF) transceiver that can be adopted in advanced metering infrastructures, universal remote controllers, smart factories, consumer electronics, and other areas. The proposed TVWS-OFDM RF transceiver consists of a receiver, a transmitter, a 25% duty-cycle local oscillator generator, and a delta-sigma fractional-N phase-locked loop. In the TV band from 470 MHz to 698 MHz, the highly linear RF transmitter protects the occupied TV signals, and the high-Q filtering RF receiver is tolerable to in-band interferers as strong as −20 dBm at a 3-MHz offset. The proposed TVWS-OFDM RF transceiver is fabricated using a 0.13-μm CMOS process, and consumes 47 mA in the Tx mode and 35 mA in the Rx mode. The fabricated chip shows a Tx average power of 0 dBm with an error-vector-magnitude of < 3%, and a sensitivity level of −103 dBm with a packet-error-rate of < 3%. Using the implemented TVWS-OFDM modules, a public demonstration of electricity metering was successfully carried out.     

浅谈“营改增”对电信行业的影响

本文着眼于“营改增”分析了其对电信行业的影响,具体探讨了电信行业的特殊性、营业税、增值税等特点,且全面分析了营业税改为增值税后的几方面的变化,综合电信行业特点提出了电信行业应对的措施建议。     

DCIM与数据中心基础设施管理

本文阐述了数据中心基础设施管理中存在的问题,DCIM的发展及其对基础设施管理的价值,DCIM在基础设施管理中的具体应用;指出DCIM关注数据的综合整理、关联、挖掘与分析,并根据分析的结果优化管理,是数据中心运营管理的发展方向。     

全双工WLAN的吞吐量性能分析

WLAN是当前移动互联网接入的重要方式之一,然而随着移动互联网用户数量的增加,WLAN接入性能迅速下降,提高在高密度部署条件下的性能是WLAN技术发展的重要方向.对IEEE 802.11协议中的基本媒体接入方法的分布式协调功能(DCF)进行了分析,建立模型分析基础架构WLAN的性能,指出在基础架构WLAN中下行吞吐率在站点数量较多情况下的瓶颈及产生瓶颈的原因.采用近年来有突破性进展的全双工技术,设计新的MAC层协议并对其性能进行分析,通过对基础架构中的AP提供全双工支持以及对DCF协议进行简单修改,使基础架构无线局域网性能可以突破瓶颈,在网络负载较高的情况下保证一定的下行吞吐率,并使总吞吐量提高60％以上.     

Comprehensive analysis of photonic nanojets in 3D dielectric cuboids excited by surface plasmons

In this paper we study the excitation of photonic nanojets (PNJ) in 3D dielectric cuboids by surface plasmons at telecommunication wavelengths. The analysis is done using the effective refractive index approach. It is shown that the refractive index contrast between the regions with and without cuboid should be roughly less than 2 in order to generate jets at the output of the cuboid. The best performance at λ₀ = 1550 nm is obtained when the height of the cuboid is 160 nm producing a jet just at the output interface with a subwavelength resolution of 0.68λ₀ and a high intensity enhancement (×5) at the focus. The multi‐wavelength response is also studied demonstrating that it is possible to use the proposed structure at different wavelengths. Finally, the backscattering enhancement is numerically evaluated by inserting a metal particle within the PNJ region, demonstrating a maximum value of ～2.44 dB for a gold sphere of radius 0.1λ₀.