首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
有线电视计算机控制收费系统是对通往用户信号传输通道进行控制处理,信号通道是可寻址的。那么,通过由有线电视收费管理软件、计算机前端控制设备及用户现场的防盗型供电器、可寻址智能分支器等组成的系统,可以对欠费的用户进行可寻址关断,即“路权控制”方式。计算机通过控制前端的数据编码器输出的信号与原有的有线电视信号混合后送入有线电视网络,在用户现场装上防盗型供电器、可寻址智能分支器,计算机控制信号通过有线电视网络送到各个可寻址智能分支器,实现对每个用户的电视信号进行电子开关控制。同时,模块化的软件设计,可根据不同区域的有线电视管理模式进行更改,彻底改变了有线电视收费管理模式,提高了有线电视台的经济效益和工作效率。  相似文献   

2.
叶彤 《安徽科技》2002,(3):46-46
有线电视计算机控制收费系统是对通往用户信号传输通道进行控制处理,信号通道是可寻址的.那么,通过由有线电视收费管理软件、计算机前端控制设备及用户现场的防盗型供电器、可寻址智能分支器等组成的系统,可以对欠费的用户进行可寻址关断,即"路权控制"方式.  相似文献   

3.
为了根据网络的业务状态动态地调整基站的开关状态以在保证用户服务质量的同时降低宏微网络的能量消耗,提出将时延限制下长期平均能耗的最小化问题映射为受限马尔科夫决策过程(constrained Markov decision process,CMDP).在该过程中把网络中每个基站的用户数目定义为系统状态,将每个小基站的开/关操作定义为网络行动.为了充分利用网络已知的先验知识加快学习速度,采用后决策状态学习算法在线更新网络的开/关策略.该算法可根据关断策略执行前已知的网络状态学习关断策略执行后未知的网络状态,从而快速制定出相应的关断策略.理论验证了后决策状态学习算法的收敛性.通过仿真对比可知,后决策状态学习算法不仅学习速度快,且可在保证网络服务质量的同时收敛到最优的基站关断节能策略.  相似文献   

4.
:HFC宽带接入网和符合 DOCSIS规范的 Cable Modem 系统的实现促使 CATV运营商考虑利用 CATV网络来开展实时的分组话音业务 .在研究了有关技术规范的基础上 ,提出了 IP电话系统在 HFC上的实现方案 ,并着重讨论了基于 Cable Modem的 IP电话用户网关的软、硬件结构和功能实现  相似文献   

5.
随着宽带接入技术的发展,各种宽带技术从不同角度为用户提供了相应的宽带接入方案。基于CATV网的多媒体远程教学系统是一个以CATV网为主要传输媒介的高速数据网,它支持广播式的单向数据传输以及通过交互网络支持双向宽带接入技术。本主要从基于CATV网的多媒体远程教学系统的特点、结构、功能等方面来介绍该系统。  相似文献   

6.
CATV网络遭受的雷击主要有两种:“直击雷”和“感应雷”。“直击雷”占雷击的概率较小,危害范围一般也较小,可使用避雷针、避雷线和避雷网来防避。“感应雷”占雷击的概率很大,CATV系统的电子设备受雷击损坏主要是由感应雷造成的。网络通过每一个有源器件安装一个接地体,实现整个网络的良好接地,可以有效地避免CATV网络受到损坏。本文对CATV系统的防雷措施进行了探讨。  相似文献   

7.
王莉 《科技信息》2007,(21):100
为保证有线电视网络始终高质量运行,满足广大用户的需求,让用户看到高质量的电视节目,农村CATV网络在每年雷雨季节,经常发生雷电打坏CATV网络设备的情况,为减少经济损失,实现整个网络的良好运行,网络的避雷与接地已显得十分重要.  相似文献   

8.
张志祥  唐海波 《科技信息》2007,(22):297-299
概述 随着邵阳电广宽带网络公司可寻址工程的不断改造,数字电视全面平移,用户不断增加,使得有线电视用户管理系统收费压力不断加大.  相似文献   

9.
本文对该台可寻址用户管理系统,以及该系统在应用中常见的故障,采取的维修方法进行了介绍。  相似文献   

10.
光纤技术在有线电视系统中的应用不仅克服了同轴电缆网络的不足,并为CATV的大规模化、多频道化、多业务化、多功能化开辟了广阔的发展道路。光纤技术在CATV系统中的应用是对CATV传输技术的一次重大变革。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

14.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

15.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

16.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

17.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

18.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

19.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

20.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号