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骨质疏松症患者PINP、25-(OH)VitD_(3)、BMP-2与中医辨证分型的相关性研究
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作者 刘莎莎 郭洪科 《四川中医》 2024年第6期87-91,共5页
目的:分析骨质疏松症患者血清总I型胶原氨基末端前肽(PINP)、25-羟维生素D3[25-(OH)VitD_(3)]及骨形态发生蛋白2(BMP-2)与其中医辨证分型的相关性。方法:收集我院2020年8月~2023年8月医院收治的157例骨质疏松症患者的一般资料及中医四... 目的:分析骨质疏松症患者血清总I型胶原氨基末端前肽(PINP)、25-羟维生素D3[25-(OH)VitD_(3)]及骨形态发生蛋白2(BMP-2)与其中医辨证分型的相关性。方法:收集我院2020年8月~2023年8月医院收治的157例骨质疏松症患者的一般资料及中医四诊资料进行回顾性分析,并统计骨质疏松症患者中医辨证分型结果,对不同症型患者基本资料、PINP、25-(OH)VitD_(3)、BMP-2水平进行比较。结果:157例骨质疏松症患者中医辨证分型属肾阳虚证34例,脾肾阳虚证43例,肝肾阴虚证49例,血瘀气滞证31例。不同中医辨证分型的骨质疏松患者血清PINP、25-(OH)VitD_(3)及BMP-2水平整体相比,差异有统计学意义(P<0.05);其中,血瘀气滞组PINP水平显著高于肾阳虚组、脾肾阳虚组及肝肾阴虚组患者(P<0.05),而其余3组两两间相比,差异无统计学意义(P>0.05);脾肾阳虚证患者25-(OH)VitD_(3)水平明显低于肾阳虚组、肝肾阴虚组及血瘀气滞组(P<0.05),且肾阳虚组低于肝肾阴虚组及血瘀气滞组(P<0.05),而其余两组相比差异无统计学意义(P>0.05);血瘀气滞组BMP-2水平显著低于肾阳虚组、脾肾阳虚组及肝肾阴虚组患者(P<0.05),而其余3组两两间相比,差异无统计学意义(P>0.05);二分类logistics回归分析结果显示,血瘀气滞与PINP呈正相关(P<0.05),与BMP-2呈负相关(P<0.05);脾肾阳虚与25-(OH)VitD_(3)呈负相关(P<0.05)。结论:骨质疏松症患者的血清PINP、25-(OH)VitD_(3)、BMP-2水平与其中医辨证分型具有一定相关性,可作为评估患者中医辨证分型的参考指标。 展开更多
关键词 骨质疏松症 总I型胶原氨基末端前肽 25-羟维生素d3 骨形态发生蛋白2 中医辨证分型
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Resource allocation method for device-to-device communications in cellular networks 被引量:2
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作者 张源 武文斌 李昕 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期361-365,共5页
Based on the conflict graph model which is formulated as a binary integer optimization problem, a resource allocation method to support device-to-device (D2D) communications in ceUular networks is proposed. First, a... Based on the conflict graph model which is formulated as a binary integer optimization problem, a resource allocation method to support device-to-device (D2D) communications in ceUular networks is proposed. First, a frequency resource assignment algorithm is presented which assigns each D2D link one frequency resource block. For this algorithm, frequency resource blocks are assigned so that the frequency resource spatial reuse opportunities in the cellular networks can be fully exploited. Then a slot scheduling algorithm is presented which schedules time slots among D2D links assigned the same frequency resource block. For this algorithm, time slot resources are scheduled so that the proportional fairness among D2D links which are assigned the same frequency resource block can be achieved. The performance of the proposed method is evaluated via computer simulations. The simulation results show that the proposed method can well support D2D communications in cellular networks. 展开更多
关键词 COMMUNICATION resource allocation device-to-device d2d
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在LTE-Advanced网络下的Device-to-Device通信 被引量:25
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作者 王彬 陈力 +1 位作者 张欣 杨大成 《现代电信科技》 2010年第7期24-27,共4页
Device-to-Device(D2D)通信是一种在系统的控制下,允许终端之间通过复用小区资源直接进行通信的新型技术,它能够增加蜂窝通信系统频谱效率,降低终端发射功率,在一定程度上解决无线通信系统频谱资源匮乏的问题。与其他应用于非许可频段... Device-to-Device(D2D)通信是一种在系统的控制下,允许终端之间通过复用小区资源直接进行通信的新型技术,它能够增加蜂窝通信系统频谱效率,降低终端发射功率,在一定程度上解决无线通信系统频谱资源匮乏的问题。与其他应用于非许可频段的同类技术相比,D2D具有干扰可控等优点。文章对D2D技术原理进行了介绍,阐述了它应用的必要性和应用场景、它对比同类技术的优点,以及在应用中的关键问题。 展开更多
关键词 device-to-device(d2d) 频谱效率 LTE-AdVANCEd
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Performance analysis of graph-based scheduling for device-to-device communications overlaying cellular networks
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作者 杜鹏 张源 《Journal of Southeast University(English Edition)》 EI CAS 2016年第3期272-277,共6页
The performance of the graph-based scheduling for device-to-device communications overlaying cellular networks is studied. The graph-based scheduling consists of two stages, the frequency assignment stage and the time... The performance of the graph-based scheduling for device-to-device communications overlaying cellular networks is studied. The graph-based scheduling consists of two stages, the frequency assignment stage and the time slot scheduling stage. For such scheduling, a theoretical method to analyze the average spectrum efficiency of the D2D subsystem is proposed. The method consists of three steps. First, the frequency assignment stage is analyzed and the approximate formula of the average number of the D2D links which are assigned the same frequency is derived. Secondly, the time slot scheduling stage is analyzed and the approximate formula of the average probability of a D2D link being scheduled in a time slot is derived. Thirdly, the average spectrum efficiency of the D2D subsystem is analyzed and the corresponding approximate formula is derived. Analysis results show that the average spectrum efficiency of the D2D subsystem is approximately inversely linearly proportional to the second- order origin moment of the normalized broadcast radius of D2D links. Simulation results show that the proposed method can correctly predict the average spectrum efficiency of the D2D subsystem. 展开更多
关键词 CELLULAR device-to-device (d2d) communication GRAPH SCHEdULING spectrum efficiency
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Outage Probability Analysis for D2D-Enabled Heterogeneous Cellular Networks with Exclusion Zone:A Stochastic Geometry Approach
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作者 Yulei Wang Li Feng +3 位作者 Shumin Yao Hong Liang Haoxu Shi Yuqiang Chen 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第1期639-661,共23页
Interference management is one of the most important issues in the device-to-device(D2D)-enabled heterogeneous cellular networks(HetCNets)due to the coexistence of massive cellular and D2D devices in which D2D devices... Interference management is one of the most important issues in the device-to-device(D2D)-enabled heterogeneous cellular networks(HetCNets)due to the coexistence of massive cellular and D2D devices in which D2D devices reuse the cellular spectrum.To alleviate the interference,an efficient interference management way is to set exclusion zones around the cellular receivers.In this paper,we adopt a stochastic geometry approach to analyze the outage probabilities of cellular and D2D users in the D2D-enabled HetCNets.The main difficulties contain three aspects:1)how to model the location randomness of base stations,cellular and D2D users in practical networks;2)how to capture the randomness and interrelation of cellular and D2D transmissions due to the existence of random exclusion zones;3)how to characterize the different types of interference and their impacts on the outage probabilities of cellular and D2D users.We then run extensive Monte-Carlo simulations which manifest that our theoretical model is very accurate. 展开更多
关键词 device-to-device(d2d)-enabled heterogeneous cellular networks(HetCNets) exclusion zone stochastic geometry(SG) Matérn hard-core process(MHCP)
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T2DM继发周围神经病变发生风险的预测列线图模型研究
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作者 仲彬 李杰 +2 位作者 陈晓倩 高媛媛 王亚梅 《临床误诊误治》 CAS 2024年第12期62-68,共7页
目的构建2型糖尿病(T2DM)继发周围神经病变风险的预警模型,并对该模型进行验证,旨在为临床评估T2DM继发周围神经病变提供可靠模型。方法选取2021年9月至2023年10月收治的T2DM继发周围神经病变患者100例作为观察组,选取单纯T2DM患者100... 目的构建2型糖尿病(T2DM)继发周围神经病变风险的预警模型,并对该模型进行验证,旨在为临床评估T2DM继发周围神经病变提供可靠模型。方法选取2021年9月至2023年10月收治的T2DM继发周围神经病变患者100例作为观察组,选取单纯T2DM患者100例作为对照组。收集2组临床资料、骨代谢标志物,随机森林算法筛选T2DM继发周围神经病变的因素,构建T2DM继发周围神经病变风险的预警列线图模型,受试者工作特征(ROC)曲线、Hosmer-Lemeshow检验评价风险预警模型的预测能力。结果观察组病程、阻塞性睡眠呼吸暂停低通气综合征(OSAHS)患者占比、收缩压、糖化血红蛋白(HbA1c)、稳态模型胰岛素抵抗指数(HOMA-IR)、同型半胱氨酸(Hcy)高于对照组(P<0.05);观察组25-羟维生素D[25-(OH)D]、Ⅰ型前胶原N-端前肽(PⅠNP)低于对照组,β-异构C-端肽(β-CTX)高于对照组(P<0.05)。随机森林算法得出T2DM继发周围神经病变前7的重要排序变量为β-CTX、HOMA-IR、HbA1c、25-(OH)D、PⅠNP、OSAHS、Hcy。基于以上因素构建T2DM继发周围神经病变风险列线图预警模型,ROC曲线显示该模型具有较高预测能力,Hosmer-Lemeshow检验显示该模型具有良好的校准能力。结论T2DM继发周围神经病变风险的因素分别为β-CTX、HOMA-IR、HbA1c、OSAHS、Hcy、25-(OH)D、PⅠNP,基于以上因素构建列线图预警模型具有良好预测能力和校准能力,可为临床防治T2DM继发周围神经病变提供参考。 展开更多
关键词 糖尿病 2 糖尿病神经病变 胰岛素抵抗指数 糖化血红蛋白 睡眠呼吸暂停 阻塞性 25-羟维生素d Ⅰ型前胶原N-端前肽
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Outage Probability Based on Relay Selection Method for Multi-Hop Device-to-Device Communication
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作者 HAI Han QIAN Hongzhi +1 位作者 FENG Hongzhan YU Jinming 《Journal of Donghua University(English Edition)》 CAS 2021年第3期214-220,共7页
To improve the connectivity of device-to-device(D2D)communication between delay-assisted vehicles,a multi-hop D2D relay selection strategy based on outage probability is proposed.The algorithm firstly clusters the rel... To improve the connectivity of device-to-device(D2D)communication between delay-assisted vehicles,a multi-hop D2D relay selection strategy based on outage probability is proposed.The algorithm firstly clusters the relay users based on the distance of D2D users,and determines the number of one-hop relay nodes through the outage probability threshold.Two-hop relay nodes directly select the same number of relays as one-hop relay nodes according to the descending order of signal noise ratio(SNR)to establish a square matrix.The Hungarian algorithm is used to assign the relay nodes of two clusters to complete the inter relay communication.Finally,the information is sent to the D2D receiver by combining technology.The simulation results show that this algorithm can reduce the cost of relay probing process and the outage probability of system in multi-hop D2D relay communication. 展开更多
关键词 multi-hop device-to-device(d2d) vehicle communication relay selection Hungarian algorithm
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Device-to-Device Based Cooperative Relaying for 5G Network:A Comparative Review
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作者 JIANG Wei 《ZTE Communications》 2017年第B06期60-66,共7页
Due to the proliferation of mobile internet access, the cellu-lar traffic is envisaged to experience a 1000-fold growth inthe second decade of the 21 st century. To meet such a hugetraffic demand, the Fifth Generation... Due to the proliferation of mobile internet access, the cellu-lar traffic is envisaged to experience a 1000-fold growth inthe second decade of the 21 st century. To meet such a hugetraffic demand, the Fifth Generation(5G) network have toadopt new techniques to substantially increase spectral effi-ciency and reliability. At the base station side, available re-sources(power supply, equipment size, processing capability,etc.) are far more sufficient than that of the terminal side,which imposes a high challenge on the uplink transmission.The concept of cooperative communications opens a possibili-ty of using multiple terminals to cooperatively achieve spa-tial diversity that is typically obtained by means of multipleantennas in the base station. The application of Device-to-Device(D2D) communications in the 3GPP LTE system fur-ther pushes the collaboration of terminals from the theory tothe practice. The utilization of D2D-based cooperative relay-ing is promising in the era of 5G. In this paper, we compara-tively study several cooperative multi-relay schemes, includ-ing the proposed opportunistic space-time coding, in thepresence of imperfect channel state information. The numeri-cal results reveal that the proposed scheme is the best coop-erative solution until now from the perspective of multiplex-ing-diversity tradeoff. 展开更多
关键词 cooperative communications device-to-device(d2d) distributed Space-Time Coding(dSTC) outdated chanel stateinformation opportunistic relaying
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SP600125对D-氨基葡萄糖衍生物诱导Eca-109细胞凋亡的影响 被引量:1
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作者 吴静 强占荣 +3 位作者 杨国栋 周永宁 王爱勤 薛群基 《中华肿瘤防治杂志》 CAS 2006年第14期1056-1059,共4页
目的:观察特异性JNK抑制剂[specificc-junNH2terminalproteinkinase(JNK)inhibitor]SP600125对D-氨基葡萄糖衍生物2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖{[2-(3-carboxy-1-oxopropyl)a-mino-2-deoxy-D-Glucose],COPADG}诱导Eca-109细... 目的:观察特异性JNK抑制剂[specificc-junNH2terminalproteinkinase(JNK)inhibitor]SP600125对D-氨基葡萄糖衍生物2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖{[2-(3-carboxy-1-oxopropyl)a-mino-2-deoxy-D-Glucose],COPADG}诱导Eca-109细胞凋亡的影响并探讨COPADG诱导Eca-109细胞凋亡的潜在分子机制。方法:体外培养Eca-109细胞,用COPADG及SP600125对细胞进行处理。细胞间接免疫荧光染色观察P-JNK蛋白表达的改变,倒置相差显微镜观察细胞形态学变化;MTT检测不同时间点的细胞活性;流式细胞术检测细胞凋亡率。结果:经SP600125处理后,COPADG诱导的Eca-109细胞P-JNK蛋白表达明显减弱,同时,COPADG诱导的Eca-109细胞凋亡率明显减低,细胞增殖抑制率下降明显,与COPADG单独作用组之间比较差异有统计学意义。结论:SP600125对D-氨基葡萄糖衍生物CO-PADG诱导Eca-109细胞凋亡具有抑制作用,并间接证明JNK信号转导通路在COPADG诱导Eca-109细胞凋亡过程中发挥着重要作用。 展开更多
关键词 2-(3-羧基-1-丙酰氨基)-2-脱氧-d-葡萄糖/药理学 食管肿瘤/病理学 蛋白激酶类/c—Jun氨基末端激酶 JNK 抑制剂(SP600125)
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细胞(d1,d2)-有向图语言类在集合论运算下的封闭性
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作者 樊建席 《青岛大学学报(自然科学版)》 CAS 1996年第3期11-13,共3页
本文给出了细胞(d1,d2)-有向图自动机类的定义及其接受的语言(判断)类的定义,并讨论了该语言(判断)类在并、交。
关键词 有向图接受器 有向图行动机 有向图语言类
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A Combining Call Admission Control and Power Control Scheme for D2D Communications Underlaying Cellular Networks 被引量:7
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作者 Xujie Li Wenna Zhang +1 位作者 Honglang Zhang Wenfeng Li 《China Communications》 SCIE CSCD 2016年第10期137-145,共9页
As device-to-device(D2D) communications usually reuses the resource of cellular networks, call admission control(CAC) and power control are crucial problems. However in most power control schemes, total data rates or ... As device-to-device(D2D) communications usually reuses the resource of cellular networks, call admission control(CAC) and power control are crucial problems. However in most power control schemes, total data rates or throughput are regarded as optimization criterion. In this paper, a combining call admission control(CAC) and power control scheme under guaranteeing QoS of every user equipment(UE) is proposed. First, a simple CAC scheme is introduced. Then based on the CAC scheme, a combining call admission control and power control scheme is proposed. Next, the performance of the proposed scheme is evaluated. Finally, maximum DUE pair number and average transmitting power is calculated. Simulation results show that D2 D communications with the proposed combining call admission control and power control scheme can effectively improve the maximum DUE pair number under the premise of meeting necessary QoS. 展开更多
关键词 device-to-device(d2d) call admission control power control cellular networks
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Secure Beamforming Design for SWIPT in Cooperative D2D Communications 被引量:5
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作者 Li Jiang Cheng Qin +1 位作者 Xixi Zhang Hui Tian 《China Communications》 SCIE CSCD 2017年第1期20-33,共14页
In device-to-device(D2D) communications, device terminal relaying makes it possible for devices in a network to function as transmission relays for each other to enhance the spectral efficiency. In this paper we consi... In device-to-device(D2D) communications, device terminal relaying makes it possible for devices in a network to function as transmission relays for each other to enhance the spectral efficiency. In this paper we consider a cooperative D2D communication system with simultaneous wireless information and power transfer(SWIPT). The cooperative D2D communication scheme allows two nearby devices to communicate with each other in the licensed cellular bandwidth by assigning D2D transmitters as half-duplex(HD) relay to assists cellular downlink transmissions. In particular, we focus on secure information transmission for the cellular users when the idle D2D users are the potential eavesdroppers. We aim to design secure beamforming schemes to maximize the D2D users data rate while guaranteeing the secrecy rate requirements of the cellular users and the minimum required amounts of power transferred to the idle D2D users. To solve this non-convex problem, a semi-definite programming relaxation(SDR) approach is adopted to obtain the optimal solution. Furthermore, we propose two suboptimal secure beamforming schemes with low computational complexity for providing secure communication and efficient energy transfer. Simulation results demonstrate the superiority of our proposed scheme. 展开更多
关键词 device-to-device(d2d) communications half-duplex relaying physical layer security secure beamforming simultaneous wireless information and power transfer
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Beamforming and Interference Cancellation for D2D Communication Assisted by Two-Way Decode-and-Forward Relay Node 被引量:4
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作者 Yiyang Ni Jie Zhao +1 位作者 Yuxi Wang Hongbo Zhu 《China Communications》 SCIE CSCD 2018年第3期100-111,共12页
This paper investigates the device-to-device(D2D) communication underlaying cellular network assisted by a two-way decode-and-forward relay node. We assume the base station(BS) is equipped with M-antenna and serves it... This paper investigates the device-to-device(D2D) communication underlaying cellular network assisted by a two-way decode-and-forward relay node. We assume the base station(BS) is equipped with M-antenna and serves its own cellular user while the D2D users communicate via a two-way decode-and-forward relay node. Both beamforming(BF) and interference cancellation(IC) strategies at the BS are considered to improve the performance for the cellular link and D2D link, respectively. We first analyze the received signal-to-interference-plus-noise for the cellular link under BF and IC strategies and then derive the exact closed-form expressions for the cellular link. Asymmetric and symmetric cases are discussed for various locations of each user. Finally, the approximations for high signal-to-noise regime are also presented. Numerical results demonstrate the accuracy of the analytical and asymptotic results. 展开更多
关键词 BEAMFORMING interference cancel-lation device-to-device (d2d) outage proba-bility relay-assisted
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Efcient Algorithms for Cache-Throughput Analysis in Cellular-D2D 5G Network 被引量:2
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作者 Nasreen Anjum Zhaohui Yang +4 位作者 Imran Khan Mahreen Kiran Falin Wu Khaled Rabie Shikh Muhammad Bahaei 《Computers, Materials & Continua》 SCIE EI 2021年第5期1759-1780,共22页
In this paper,we propose a two-tiered segment-based Device-toDevice(S-D2D)caching approach to decrease the startup and playback delay experienced by Video-on-Demand(VoD)users in a cellular network.In the S-D2D caching... In this paper,we propose a two-tiered segment-based Device-toDevice(S-D2D)caching approach to decrease the startup and playback delay experienced by Video-on-Demand(VoD)users in a cellular network.In the S-D2D caching approach cache space of each mobile device is divided into two cache-blocks.The rst cache-block reserve for caching and delivering the beginning portion of the most popular video les and the second cacheblock caches the latter portion of the requested video les‘fully or partially’depending on the users’video watching behaviour and popularity of videos.In this approach before caching,video is divided and grouped in a sequence of xed-sized fragments called segments.To control the admission to both cacheblocks and improve the system throughput,we further propose and evaluate three cache admission control algorithms.We also propose a video segment access protocol to elaborate on how to cache and share the video segments in a segmentation based D2D caching architecture.We formulate an optimisation problem and nd the optimal cache probability and beginning-segment size that maximise the cache-throughput probability of beginning-segments.To solve the non-convex cache-throughout maximisation problem,we derive an iterative algorithm,where the optimal solution is derived in each step.We used extensive simulations to evaluate the performance of our proposed S-D2D caching system. 展开更多
关键词 device-to-device(d2d) startup-delay playback-delay CACHING
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Security Rate Optimization of D2D Communication Based on Power Control 被引量:2
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作者 王珍 李莉 +1 位作者 龚帅 叶鹏 《Journal of Donghua University(English Edition)》 EI CAS 2017年第5期624-629,共6页
An optimization of device-to-device(D2D) security rate algorithm based on power control is provided to enhance the physical layer security underlaying D2D communication and guarantee the data rate requirement of the c... An optimization of device-to-device(D2D) security rate algorithm based on power control is provided to enhance the physical layer security underlaying D2D communication and guarantee the data rate requirement of the cellular user(CU) at the same time.First,a scenario model is set up,in which an eavesdropper is considered to wiretap the information of D2D transmitters.Then,a secure region of D2D communication is proposed.When D2D communication users reside outside the secure region,the spectrum of CU's is not allowed to share with the D2D communication so as to avoid eavesdropper tapping useful information of D2D communication.When D2D communication users reside inside the secure region,the security rate of D2D is maximized by optimization of the transmitting power of D2D and CU.The simulation results showthat the achieved D2D security rate of the proposed algorithm increases 2.8 bps/Hz when the signal to noise ratio(SNR) is 15 d B,compared with that when the random access algorithm is used. 展开更多
关键词 device-to-device(d2d) security rate secure region power control
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Energy-Efficient Architecture and Technologies for Device to Device(D2D) Based Proximity Service 被引量:5
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作者 ZHANG Bo WANG Yufeng +1 位作者 JIN Qun MA Jianhua 《China Communications》 SCIE CSCD 2015年第12期32-42,共11页
Considering that modern mobile terminals possess the capability to detect users' proximity,and offer means to directly communicate and share content with the people in close area,Device-to-Device(D2D) based Proxim... Considering that modern mobile terminals possess the capability to detect users' proximity,and offer means to directly communicate and share content with the people in close area,Device-to-Device(D2D) based Proximity Services(ProSe) have recently witnessed great development,which enable users to seek for and utilize relevant value in their physical proximity,and are capable to create numerous new mobile service opportunities.However,without a breakthrough in battery technology,the energy will be the biggest limitation for ProSe.Through incorporating the features of ProSe(D2D communication technologies,abundant built-in sensors,localization-dependent,and context-aware,etc.),this paper thoroughly investigates the energy-efficient architecture and technologies for ProSe from the following four aspects:underlying networking technology,localization,application and architecture features,context-aware and user interactions.Besides exploring specific energy-efficient schemes pertaining to each aspect,this paper offers a perspective for research and applications.In brief,through classifying,summarizing and optimizing the multiple efforts on studying,modeling and reducing energy consumption for ProSe on mobile devices,the paper would provide guide for developers to build energy-efficient ProSe. 展开更多
关键词 aware localization terminals users networking utilize Bluetooth d2d battery enable
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Admission control based on beamforming and interference alignment for D2D communication underlaying cellular networks 被引量:1
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作者 Wang Gang Li Yongmei +2 位作者 Meng Chao Wang Hao Heng Wei 《Journal of Southeast University(English Edition)》 EI CAS 2019年第1期1-7,共7页
An admission control algorithm based on beamforming and interference alignment for device-to-device( D2D) communication underlaying cellular networks is proposed. First, some portion of D2D pairs that are the farthest... An admission control algorithm based on beamforming and interference alignment for device-to-device( D2D) communication underlaying cellular networks is proposed. First, some portion of D2D pairs that are the farthest away from the base station( BS) is selected to perform joint zero-forcing beamforming together with the cellular user equipments( UEs) and is admitted to the cellular network. The interference of the BS transmitting signal to the cellular UEs and the portion of D2D pair is eliminated completely at the same time. Secondly,based on the idea of interference alignment,the definition of channel parallelism is given. The channel parallelism of the remaining D2D pairs which are not involved in joint zero-forcing beamforming is computed by using the channel state information from the BS to the D2D devices. The higher the channel parallelism,the less interference the D2D pair suffers from the BS. Finally,in a descending order of channel parallelism,the remaining D2D pairs are reviewed in succession to determine admission to the cellular network. The algorithm stops when the admission of a D2D pair decreases the system sum rate. Simulation results show that the proposed algorithm can effectively reduce the interference of the BS transmitting signal for D2D pairs and significantly improve system capacity. Furthermore, D2D communication is more applicable to short-range links. 展开更多
关键词 device-to-device(d2d)communication cellular network admission control BEAMFORMING interference alignment
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Energy Efficiency Optimization for D2D Communications Based on SCA and GP Method 被引量:3
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作者 Xiaozheng Gao Hangcheng Han +1 位作者 Kai Yang Jianping An 《China Communications》 SCIE CSCD 2017年第3期66-74,共9页
In this paper, we propose an energy-efficient power control scheme for device-to-device(D2D) communications underlaying cellular networks, where multiple D2D pairs reuse the same resource blocks allocated to one cellu... In this paper, we propose an energy-efficient power control scheme for device-to-device(D2D) communications underlaying cellular networks, where multiple D2D pairs reuse the same resource blocks allocated to one cellular user. Taking the maximum allowed transmit power and the minimum data rate requirement into consideration, we formulate the energy efficiency maximization problem as a non-concave fractional programming(FP) problem and then develop a two-loop iterative algorithm to solve it. In the outer loop, we adopt Dinkelbach method to equivalently transform the FP problem into a series of parametric subtractive-form problems, and in the inner loop we solve the parametric subtractive problems based on successive convex approximation and geometric programming method to obtain the solutions satisfying the KarushKuhn-Tucker conditions. Simulation results demonstrate the validity and efficiency of the proposed scheme, and illustrate the impact of different parameters on system performance. 展开更多
关键词 device-to-device(d2d) communications power control energy efficiency(EE) successive convex approximation(SCA) geometric programming(GP)
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老年2型糖尿病患者空腹C肽、25-羟基维生素D水平与骨密度的关系研究 被引量:3
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作者 张翠兰 赵汉儒 +5 位作者 李玲 苏佩琼 黎宝仁 蓝燕 彭菊桃 陈雪丽 《解放军医药杂志》 CAS 2022年第2期83-86,共4页
目的研究老年2型糖尿病患者骨密度与空腹C肽、25-羟基维生素D水平的相关性。方法选取2018年5月—2019年5月收治的老年2型糖尿病132例作为老年2型糖尿病组,其中骨量正常组50例,骨量减少组42例,骨质疏松组40例;另外选取同期行健康体检的... 目的研究老年2型糖尿病患者骨密度与空腹C肽、25-羟基维生素D水平的相关性。方法选取2018年5月—2019年5月收治的老年2型糖尿病132例作为老年2型糖尿病组,其中骨量正常组50例,骨量减少组42例,骨质疏松组40例;另外选取同期行健康体检的正常老年人50例作为健康对照组。检测所有受试者骨密度及血清空腹C肽、25-羟基维生素D水平,分析空腹C肽、25-羟基维生素D、临床生化指标与骨密度的关系,以及空腹C肽、25-羟基维生素D、骨密度的相关性。结果老年2型糖尿病组骨密度、空腹C肽、25-羟基维生素D水平低于健康对照组(P<0.05)。骨量减少组、骨质疏松组空腹C肽、25-羟基维生素D水平低于骨量正常组,且骨质疏松组低于骨量减少组(P<0.05)。骨量减少组、骨质疏松组血清钙、血磷、骨钙素(BGP)水平低于骨量正常组,24 h尿蛋白定量、糖化血红蛋白、Ⅰ型胶原胶联蛋白羧基末端肽(CTX-Ⅰ)水平高于骨量正常组(P<0.05);骨质疏松组血清钙、血磷、BGP水平低于骨量减少组,24 h尿蛋白定量、糖化血红蛋白、CTX-Ⅰ水平高于骨量减少组(P<0.05)。骨密度与空腹C肽呈正相关(r=0.304,P=0.007);骨密度与25-羟基维生素D呈正相关(r=0.198,P=0.023);空腹C肽与25-羟基维生素D呈正相关(r=0.397,P=0.001)。结论老年2型糖尿病患者骨密度与空腹C肽、25-羟基维生素D相关,且与骨代谢指标水平有关。 展开更多
关键词 糖尿病 2 骨密度 C肽 25-羟基维生素d 骨钙素 Ⅰ型胶原胶联蛋白羧基末端肽
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Novel dynamic anti-collusion ciphertext policy attribute-based encryption scheme in 5G D2D environment
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作者 Xu Xiangjie Jiang Rui 《Journal of Southeast University(English Edition)》 EI CAS 2021年第3期251-257,共7页
To share data securely with secure attribute revocation,anti-collusion,and dynamic user management in the 5G device-to-device(D2D)environment,a novel dynamic anti-collusion ciphertext policy attribute-based encryption... To share data securely with secure attribute revocation,anti-collusion,and dynamic user management in the 5G device-to-device(D2D)environment,a novel dynamic anti-collusion ciphertext policy attribute-based encryption(NDA-CP-ABE)scheme in the 5G D2D environment is proposed.On the basis of the ciphertext policy attribute-based encryption algorithm,fine-grained access control and secure attribute revocation are realized,and the confidentiality of data is guaranteed.A polynomial function is adopted in the ciphertext generation phase to realize dynamic user management.A random number is used to prevent a collusion attack among the legitimate user equipment(UE),revoked UE,and external network attackers.Finally,on the basis of the Diffie-Hellman problem,the NDA-CP-ABE scheme is formally proved,and the simulation performances are compared with those of similar schemes.The results show that data can be securely shared through a D2D channel with secure attribute revocation,anti-collusion,and dynamic user management.Moreover,compared with similar schemes,the NDA-CP-ABE scheme has higher efficiency in encryption,decryption,and storage. 展开更多
关键词 device-to-device(d2d) attribute revocation user management dynamic anti-collusion ciphertext policy attribute-based encryption(NdA-CP-ABE) access control
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