Land potential appraisal for urban land reserve based on GIS: A case of metropolitan area in Chongqing

With the rapid urbanization, land banking has become an important means for rational land use and land configuration optimizing. Rational urban land reserve and supply plan are keys for an urban land banking. GIS has been used to model urban growth, growth at the rural-urban fringe specifically. This paper identifies that the urban land banking potential can be evaluated based on RS and GIS technology. 10 indicators were chosen in the integrated index system. As a case of Metropolitan area in Chongqing, urban land banking potential was evaluated based on RS and GIS technology. With GIS, two steps can help to finish potential analysis of land banking. One is goal driven process, such as the process of planning and definition; the other step is data-driven process, such as the process of Manipulating. The results are used to establish the current land banking plan.     

Analysis and compare of location technologies supporting LBS

Location technology is the key part of location based service. Different technologies have different accuracy, modifying to network and cost of operating. Also these technologies have limitation to network. This paper compares existing popular location technologies and gives some suggestions about choosing of location technologies in GSM and CDMA systems.     

Hybrid location determination technology within urban and indoor environmeng based on Cell _ID and path loss

The location determination technology based on simple delay evaluations or GPS is not accurate enough or even impossible in urban and indoor environments due to the multi-path propagation. To enhance the location accuracy and reduce the operation cost within these environments，this paper proposes a novel hybrid location determination technology which combines CELL-ID with the database correlation method. The proposed method generate the prediction database of path loss according to CELL-ID，and after the computation the smallest squared error of measured path loss and the prediction path loss，the location of the mobile terminal is decided by the coordinates of the best matching matrix entry.     

Y1.95-xGdxSiO5:Eu0.05的真空紫外光谱

利用高温固相法合成了Ｙ１．９５－ｘＧｄｘＳｉＯ５：Ｅｕ０．０５（ｘ＝０．６ｍｏｌ％）荧光体。结构测定表明所合成的荧光体为单斜晶系的Ｘ２型Ｙ２ＳｉＯ５相,空间群为Ｂ２／ｂ。真空紫外光谱表明：随着Ｇｄ＾３＋含的增加,在１９２ｎｍ附近,出现了Ｇｄ＾３＋的激发峰,且此峰的强度随着Ｇｄ＾３＋含量的增加而增在;同时位于１５０￣１８５ｎｍ之间的基质吸收带的强度也增大;而位于２００￣３００ｎｍ之间的Ｅｕ的电荷迁移     

YP1xVxO4∶Eu3+在真空紫外区发光的优化

系统地考查了Eu3 + 在YPO4 YVO4 固溶体中的发光。当V5+ 的浓度低于 0 3 ,出现VO4 3 -离子团的蓝色发射 ;直到V5+ 的浓度等于或大于 0 3时 ,VO4 3 -离子团的蓝色发射才被Eu3 + 离子的红色发射所猝灭 ,发射主波长在 61 9nm。在真空紫外线的激发下 ,Eu3 + 在YPO4 YVO4 固溶体有较强发光 ,并随着P5+ 浓度的增加 ,Eu3 + 离子的发光增强。经过优化的组成为YP0 7V0 3 O4 ∶Eu3 + 的荧光粉在真空紫外激发下既具有较强的发光 ,又具有优良的色纯度 ,将是一种新型的良好的等离子体平板显示用荧光粉。     

基于RFID位置语义的室内移动轨迹聚类算法

面向室内空间的移动轨迹聚类有利于发现室内热点和用户移动模式.针对室内环境在定位技术、距离度量等方面的特殊性,充分考虑室内移动轨迹的空间和语义特征,提出一种基于无线射频识别(radio frequency identi-fication,RFID)位置语义的室内移动轨迹聚类方法.该方法对原始轨迹提取特征点,可简化轨迹以降低算法时间复杂度;从空间形状和位置语义2个方面加权计算轨迹相似度,其中,空间相似度通过定义适用于室内三维空间的距离函数来计算,语义相似度计算基于最长公共子序列思想,并引入移动对象在轨迹点的到达时间和停留时间;利用线性表存储轨迹相似度,采用改进的层次聚类方法对移动轨迹进行聚类.实验结果表明,该方法能够有效地进行室内轨迹聚类并具有较高的效率.     

A novel assistance data processing method for AGPS location system

A method for efficiently transmitting location assistance information to an MS (mobile station) over a control channel with minimal impact on the capacity of the control channel. A location server provides a difference between satellite positions that have been computed using Almanac data and Ephemeris data. Sending only the difference between the positions and satellite clock corrections computed using the two different data types. The total amount of information to be transmitted to a MS is significantly reduced. Furthermore, by providing rate of change information, the method allows the location assistance information to remain valid for a relatively long time after it has been received by the MS.     

Indexing large moving objects from past to future with PCFI

In moving object database, the moving objects' current position must be kept in memory, also to the trajectory, in some case, as same as the future. But the current existing indexes such as SEB-tree, SETI-tree, 2+3R-tree, 2-3RT-tree and etc. can only provide the capability for past and current query, and the TPR-Tree, TPR*-Tree and etc.can only provide the capability for current and future query. None of them can provide a strategy for indexing the past, current and also the future information of moving objects.In this paper, we propose the past-current-future Index (PCFI-Index) to index the past,current & future information of the moving objects. It is the combination of SETI-tree and TPR*-tree, the SETI liking index is used for indexing the historical trajectory segments except the front line structure, and the moving objects' current positions, velocities are indexed via the in-memory frontline structure which mainly implemented with TPR*-tree.Considering the large update operations on TPR-tree of large population, a hash table considering cache sensitivity is also introduced. It works with the frontline part, leading a bottom-up update of the tree. The performance analysis proves that the PCFI-index can handle most of the query efficiently and provides a uniform solution for the trajectory query, time-slice query, internal query and moving query.     

Analysis and compare of location technologies supporting LBS

Location technology is the key part of location based service. Different technologies have different accuracy,modifying to network and cost of operating. Also these technologies have limitation to network. This paper compares existing popular location technologies and gives some suggestions about choosing of location technologies in GSM and CDMA systems.     

时空数据模型的初步设计

时空数据库用于模拟和查询位置或形状随时间改变的移动对象。提出了用于表示移动对象的时空数据类型和扩展数据类型。并在此基础上，对时空操作符也作了相应的概括。该数据模型便于实现，并能较好地支持时空查询。