A novel low-complexity power allocation algorithm based on the NOMA system in a low-speed environment

For future wireless communication systems, Power Domain Non-Orthogonal Multiple Access (PD-NOMA) using an advanced receiver has been considered as a promising radio access technology candidate. Power allocation plays an important role in the PD-NOMA system because it considerably affects the total throughput and Geometric Mean User Throughput (GMUT) performance. However, most existing studies have not completely accounted for the computational complexity of the power allocation process when the User Terminals (UTs) move in a slow fading channel environment. To resolve such problems, a power allocation method is proposed to considerably reduce the search space of a Full Search Power (FSP) allocation algorithm. The initial power reallocation coefficients will be set to start with former optimal values by the proposed Lemma before searching for optimal power reallocation coefficients based on total throughput performance. Step size and correction granularity will be adjusted within a much narrower power search range while invalid power combinations may be reasonably discarded during the search process. The simulation results show that the proposed power reallocation scheme can greatly reduce computational complexity while the total throughput and GMUT performance loss are not greater than 1.5% compared with the FSP algorithm.     

码资源利用率提升方案

TD-SCDMA网络经过4期的建设后,覆盖日臻完善,TD-SCDMA用户快速发展但有相当部分的用户和业务长期驻留和承载在GSM网,导致目前GSM网络利用率持续攀升,峰值网络利用率可以达到80％,而TD-SCDMA网的码资源利用率还不到12％.详细介绍了采取功率提升,2G/3G互操作参数优化及引导用户使用TD网络等三种措施,在保障用户使用感知度和不影响网络KIP指标的基础上,有效提升TD网络码资源利用率的承载能力,达到GSM向TD-SCDMA网分流的效果.     

差别电价及其对电力市场的影响

差别电价是政府倡导、电力行业试行的电力营销策略。本文从经济学原理出发,研究了差别电价的经济学基础和法规依据,并分析了差别电价制度对电力市场的影响,以期为差别电价的政策执行提供有益的借鉴。     

Relationship between HOMO energy level and open circuit voltage of polymer solar cells

A series of π-conjugated polymers (PDHF-BT and PDHF-TBT) with 4-(3,4-ethylenedioxythienyl)-2,1,3-benzothiadiazole (BT), 4,7-bis(3,4-ethylenedioxythienyl)-2,1,3-benzothiadiazole (TBT), and 9,9′-dihexylfluorene were synthesized by the Suzuki coupling reaction. The HOMO energy level of PDHF-BT was −5.47 eV, which was lower than that of PDHF-TBT (−5.22 eV), while the LUMO energy level of PDHF-BT (−3.45 eV) was very similar to that of PDHF-TBT (−3.42 eV). These energy levels of PDHF-BT and PDHF-TBT were also supported by a DFT calculation. The power conversion efficiency (PCE) of the polymer solar cell (PSC) with a structure of ITO/PEDOT:PSS/PDHF-BT:PCBM (1:1)/Al was determined as 0.34% and it was larger than that of the device based on PDHF-TBT (0.22%). Correspondingly, the V_oc of the PSC based on PDHF-BT (0.71 V) was much larger than that of the device based on PDHF-TBT (0.40 V). The results support that the V_oc of polymer based PSCs is strongly related to the HOMO energy level of the active polymers.     

Key processing with control vectors

A method is presented for controlling cryptographic key usage based on control vectors. Each cryptographic key has an associated control vector that defines the permitted uses of the key within the cryptographic system. At key generation, the control vector is cryptographically coupled to the key by way of a special encryption process. Each encrypted key and control vector are stored and distributed within the cryptographic system as a single token. Decryption of a key requires respecification of the control vector. As part of the decryption process, the cryptographic hardware verifies that the requested use of the key is authorized by the control vector. This article focuses mainly on the use of control vectors in cryptosystems based on the Data Encryption Algorithm.     

IMT系统对1518～1525 MHz频段卫星移动系统的干扰

为分析在1 518～1 525MHz频段附近部署IMT系统的可行性,在梳理了国际电信联盟建议书和《无线电规则》的基础上,通过理论分析和仿真计算等手段,就1 492～1 518MHz频段IMT系统对1 518～1 525MHz频段卫星移动系统的干扰问题进行了深入分析.针对IMr系统基站对卫星移动系统终端在不同场景下的干扰链路,采用蒙特卡洛仿真方法对阻塞干扰与邻频干扰进行计算仿真.仿真结果给出了不同场景下的阻塞干扰概率以及两个系统邻频共存的条件.研究结果可为我国无线电管理部门对该频段邻频的未来规划提供理论支撑.     

搞好闭环管理 提高可靠性水平

本文以作者十年来从事元器件选用、检验、筛选、失效分析等工作实践为基础,阐述了搞好元器件的闭环管理,对提高军用电子设备的可靠性的重大意义。     

Energy Efficient Forwarding Algorithm in Opportunistic Networks

In opportunistic networks,a successful message transmission between node pairs depends on the message size,the transmission speed and the connection duration time.This paper proposes a new message forwarding algorithm to improve the message delivery ratio and reduce the energy consumption.Previous encounter characteristics between nodes are used to estimate future connection duration time using a three point estimation method.Furthermore,the buffer utilization of nodes is used as a weight for the likelihoods to meet destinations according to the hop count of messages stored in the buffer.The simulation results show that the proposed forwarding algorithm achieves higher delivery ratio and less overhead ratio than the other four popular routing protocols.In addition,the proposed algorithm gains a better average residual energy performance among all the compared protocols.     

输电线现场安全作业指挥装置意义

据调查,由于人的因素造成事故占电力建设施工企业事故总数85%以上.人为因素主要表现为:违章作业、冒险蛮干、误操作、应变能力差等.从事故受害者来看,绝大多数都是起重工、电工、架子工、铁工、水泥工等现场作业人员,只有极少数现场施工管理人员,因此,努力做好施工现场作业人员的安全管理极为重要.     

应用计算机加强天气预报信息管理的作用

天气预报,主要是借助卫星等现代化设备,实现对气象信息的检测,通过相关软件和模式的分析,实现对未来天气的预知、探测和发布,以满足人们对气象信息的需要。气象部门在进行天气预报探测过程中,根据计算机技术的运行特点和高效管理,全面运用计算机技术,有利于实现对天气预报信息的科学监测和管理,以推动天气预报技术的全面发展。本文对应用计算机加强天气预报信息管理的作用进行探讨,以实现对天气预报信息管理的全面认识,结合计算机的相关技术,制定合理的应用策略,以提高天气预报信息管理的准确性和科学性,进而促进天气预报技术的发展。