CN101355583B - Method for searching buffer based on loose location dependence in wireless self-networking - Google Patents

Method for searching buffer based on loose location dependence in wireless self-networking Download PDF

Info

Publication number
CN101355583B
CN101355583B CN2008101960417A CN200810196041A CN101355583B CN 101355583 B CN101355583 B CN 101355583B CN 2008101960417 A CN2008101960417 A CN 2008101960417A CN 200810196041 A CN200810196041 A CN 200810196041A CN 101355583 B CN101355583 B CN 101355583B
Authority
CN
China
Prior art keywords
user
result
searching
request
loose
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN2008101960417A
Other languages
Chinese (zh)
Other versions
CN101355583A (en
Inventor
王义麟
李文中
陆桑璐
陈道蓄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing University
Original Assignee
Nanjing University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing University filed Critical Nanjing University
Priority to CN2008101960417A priority Critical patent/CN101355583B/en
Publication of CN101355583A publication Critical patent/CN101355583A/en
Application granted granted Critical
Publication of CN101355583B publication Critical patent/CN101355583B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Abstract

The invention discloses a method for searching a buffer memory based on loose position dependence in a wireless ad-hoc network. The searching process under the mode of loose position dependence comprises the following steps of: 1) generating a request; 2) searching a local buffer memory, and executing step 3) if no result; 3) sending a searching request to a neighbored user who executes the local searching of step 2) and returns a result to the user who submits the request and selects an optimal result, and executing step 4) if no result; and 4) submitting a searching request to a server to return the optimal result. The user can add overhead which can be afforded by the user according to particular conditions when the user submits the searching request, and determines whether buffer data is available or not through comparing effective areas of the buffer data and corresponding restriction values. The method not only improves the hit rate of the buffer memory, but also reduces the energy consumption during the process of communication transmission.

Description

In the wireless self-networking based on the method for searching buffer of loose location dependence
Technical field
The present invention relates to the data cached management of dependence information service in position in the wireless self-networking, specially refer to definition and describing method for data cached space effective zone.
Technical background
Position dependent information service (Location Dependent Information Services is called for short LDISs) is current moving and next type of general environment important use.Different with information service in the past, rely on the request that the user proposes in the information service in the position and in global scope, possibly have a plurality of alternative results, and actually which to be only the user needed, be that the geographical location information when being initiated by request determines.Along with wireless and popularization general fit calculation, a large amount of position dependent information services like traffic inquiry and automobile navigation etc., has demonstrated great application prospect.Different with wire communication, this category information service facing many-sided problem under wireless environment, and caching technology has very positive effect to promoting this type of systematic function.
In the position relies on information service, except Data Update, data cachedly also can become invalid data, promptly so-called " cache invalidation that the position relies on " owing to user's position change.In order to solve the cache invalidation problem that the position relies on, can in data cached, preserve the effective coverage of these data usually, the user just can judge whether this is data cached effective based on the effective coverage in this locality like this.Need extra storage and transport overhead yet preserve the effective coverage, therefore how to define effectively and represent that the effective coverage becomes important research contents in the cache invalidation research that the position relies on.
Existing research only is confined to strict position dependence for the definition of effective coverage; The effective coverage that is each data object is disjoint; Appoint and give a query requests; This object a suitable data object arranged and only has, if not in local cache, then must obtain from server in arbitrary zone.And in a large amount of practical applications, user's request need not returned optimal results, as long as object within user's acceptable scope, can return to the user as suitable result.The benefit of introducing this loose restriction relation be more to fit user's actual request provides more alternative result simultaneously, can obviously improve the hit rate of buffer memory.Existing work can not define the restriction relation of this " loose ", so we need define new describing method.
Summary of the invention
The objective of the invention is to rely on the position dependence of information service, proposed a kind of definition and described the new method that loose location dependence concerns to position in the wireless self-networking.
Based on the method for searching buffer of loose location dependence, it is characterized in that in a kind of wireless self-networking of the present invention with space constraint (r), internal object collection (P In) and peripheral object set (P Out) a data object q described 0Loose effective coverage, and the search procedure under the loose location dependence pattern comprises following 4 steps:
1) generates request Q (X, (xc, yc), Δ d);
2) if local cache search is no result execution in step 3 then);
3) send searching request to neighbours user, each neighbours user's execution in step 2) local search, the result is returned the generation requesting users, select optimum result by this user, if no result execution in step 4 then);
4) submit searching request to server, return optimal result by server.
For given q 0And r, the building method of loose effective coverage is: make Poly iThe q that expression is divided with Voronoi figure i(i=1 ..., the limit collection of effective coverage N) is at first q iBy arriving q 0Distance sort from small to large, take out nearest object q k, do curve f (M (x, y)): | q 0M|-||q kIf M|=r is this curve and Poly kIntersection point be less than 2, then get next object and repeat aforesaid operations, if this curve and Poly k2 intersection point P are arranged 1And P 2(the q of this moment kBe a peripheral object), get an intersection point P 2, then must have another object q K ', P 2Also at Poly K 'A limit on, do new curve f ' (M (x, y)): | q 0M|-|q K 'M|=r obtains another intersection point P 3, go down to obtain new intersection point P successively 4, P 5..., P mOwing to cross some P 1, P 2..., P mZone with the hyperbolic line segment is surrounded is sealed, i.e. P M+1=P 1, q so far 0The limit collection structure of loose effective coverage accomplish, also found out all peripheral objects simultaneously, the internal object collection just can be confirmed in the position that next can contrast each data object, promptly is positioned at other alternative data objects of this loose effective coverage.
Above-mentioned steps 2) process is: the search local cache, find out alternative result set Ai}, i.e. its loose effective coverage coverage rate user's current location, for each Ak ∈ Ai}, if its space constraint value rk≤Δ d, then Ak is suitable Search Results of Q; Otherwise, find out that (coordinate is nearest alternative objects qx (the ∈ P of M (xc, yc)) from Q In), make e=|qkM|-|qxM|, if e>=Δ d, then Ak also be suitable result of Q, returns the suitable result with minimum e, as if no result execution in step 3 then
According to the present invention; User's its overhead that can bear of affix (comparing the expense that need pay more with optimal result) as the case may be when proposing searching request is through comparing data cached effective coverage and corresponding binding occurrence decides this data cached whether available.This method had both improved the hit rate of buffer memory, had also reduced the energy expense in the communication transmission process simultaneously.
Description of drawings
Fig. 1 is the effective coverage sketch map under the loose location dependence pattern;
Fig. 2 is the search procedure sketch map under the loose location dependence pattern.
Embodiment
Wireless self-networking is made up of base station and one group of mobile terminal device (being the user), and one group of portable terminal is interconnected to form a self-organizing network.Each portable terminal all has the function of data route, can be other device forwards data.The base station is a fixing accessing points, can be regarded as a data server, and the data of all requests of portable terminal can be got from the base station.The part portable terminal is positioned at the communication range of base station, they can with the base station direct communication.If a portable terminal is positioned at outside the communication range of base station, it can pass through the multi-hop communication mode, utilizes other-end to transmit, thereby can have access to the data of base station.There are a plurality of alternative data objects (its physical location is fixed) in a searching request for portable terminal proposes in global scope, when the user proposed searching request, service routine can be confirmed suitable data object according to user's current location.
Based on the loose request of loose location dependence pattern, for example " look near the hotel the family, the there from the distance of current position compared with no more than 100 meters of the distance in a nearest tame hotel ", its user can bear overhead (Δ d) for walking 100 meters more.Fig. 1 is the effective coverage sketch map under the loose location dependence pattern, wherein data object q 2For from the nearest alternative objects of user M, q 1The distance that leaves the user is than q 2Δ d rice far away.Can object of proof q 1Be that the loose effective coverage of binding occurrence is the closed area that is surrounded by one group of hyperbolic line segment with Δ d.
We are with space constraint (r), internal object collection (P In) and peripheral object set (P Out) a data object q described 0Loose effective coverage.Wherein the border of loose effective coverage is by r and P OutConfirm P InBe used to calculate q 0And the difference between the actual optimum result of request.
For given q 0Can find a unique description with r, concrete grammar is following: make Poly iThe q that expression is divided with Voronoi figure i(i=1 ..., the limit collection of effective coverage N), at first we are q iBy arriving q 0Distance sort from small to large, take out nearest object q k, do curve f (M (x, y)): | q 0M|-|q kIf M|=r is this curve and Poly kIntersection point be less than 2, then get next object and repeat aforesaid operations.If this curve and Poly k2 intersection point P are arranged 1And P 2(the q of this moment kBe a peripheral object), get an intersection point P 2, then must have another object q k, P 2Also at Poly K 'A limit on.Do new curve f ' (M (x, y)): | q 0M|-|q K 'M|=r obtains another intersection point P 3, go down to obtain new intersection point P successively 4, P 5..., P mOwing to cross some P 1, P 2..., P mZone with the hyperbolic line segment is surrounded is sealed, i.e. P M+1=P 1So far q 0The limit collection structure of loose effective coverage accomplish, also found out all peripheral objects simultaneously.Internal object collection (being positioned at other alternative data objects of this loose effective coverage) just can be confirmed in the position that next can contrast each data object.
Search procedure under the loose location dependence pattern can be divided into 4 steps (as shown in Figure 2).
1. generate request Q (X, (xc, yc), Δ d).
2. the search local cache is found out alternative result set { Ai}, i.e. its loose effective coverage covering user's current location.For each Ak ∈ Ai}, if its space constraint value rk≤Δ d, then Ak is suitable Search Results of Q; Otherwise, find out that (coordinate is nearest alternative objects qx (the ∈ P of M (xc, yc)) from Q In), make e=|qkM|-|qxM|, if e>=Δ d, then Ak also is suitable result of Q.Return suitable result, if no result execution in step 3 then with minimum e.
3. send searching request to neighbours user, each neighbours user carries out local search (with step 2), and the result is returned the generation requesting users, selects to have the suitable result of minimum e by this user, if no result execution in step 4 then.
4. submit searching request to server, return optimal result by server.

Claims (1)

  1. In the wireless self-networking based on the method for searching buffer of loose location dependence, it is characterized in that with space constraint r, internal object collection P InWith peripheral object set P OutA data object q is described 0Loose effective coverage: for given q 0And r, make Poly iThe q that expression is divided with Voronoi figure iThe limit collection of effective coverage, i=1 wherein ..., N is at first q iBy arriving q 0Distance sort from small to large, take out apart from q 0Nearest object q k, do curve f (M (x, y)): | q 0M|-|q kIf M|=r is this curve and Poly kIntersection point be less than 2, then get next apart from q 0Nearest object q nRepeat aforesaid operations, promptly make curve f " (M (x, y)): | q 0M|-|q nIf M|=r is this curve and Poly n2 intersection point P are arranged 1And P 2, get an intersection point P 2, then must have another object q k', P 2Also at Poly k' a limit on, do new curve f ' (M (x, y)): | q 0M|-|q k' M|=r obtains another intersection point P 3, go down to obtain new intersection point P successively 4, P 5..., P mOwing to cross some P 1, P 2..., P mZone with the hyperbolic line segment is surrounded is sealed, i.e. P M+1=P 1, q so far 0The limit collection structure of loose effective coverage accomplish, also found out all peripheral objects simultaneously, the internal object collection just can be confirmed in the position that next contrasts each data object, promptly is positioned at other alternative data objects of this loose effective coverage; And comprise following 4 steps based on the method for searching buffer of loose location dependence:
    1) (wherein, X is the data object of being asked for X, (xc, yc), Δ d), and (xc is the coordinate that the user sends the position M of request Q yc), and Δ d is the overhead that the user can bear to generate request Q;
    2) the search local cache is found out the set of all data of loose effective coverage coverage rate user's current location, as alternative result set Ai}, and for each Ak ∈ Ai}, if its space constraint value rk≤Δ d, then Ak is suitable Search Results of Q; Otherwise, find out the nearest alternative objects qx of position M that sends request Q from the user, qx ∈ P In, make e=|AkM|-|qxM|, if e≤Δ d, then Ak also be suitable result of Q, returns the suitable result with minimum e, as if no result execution in step 3 then);
    3) send searching request to neighbours user, each neighbours user's execution in step 2), the result is returned the generation requesting users, select optimum result by this user, finish; If no result is execution in step 4 then);
    4) submit searching request to server, return optimal result by server.
CN2008101960417A 2008-09-11 2008-09-11 Method for searching buffer based on loose location dependence in wireless self-networking Expired - Fee Related CN101355583B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN2008101960417A CN101355583B (en) 2008-09-11 2008-09-11 Method for searching buffer based on loose location dependence in wireless self-networking

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN2008101960417A CN101355583B (en) 2008-09-11 2008-09-11 Method for searching buffer based on loose location dependence in wireless self-networking

Publications (2)

Publication Number Publication Date
CN101355583A CN101355583A (en) 2009-01-28
CN101355583B true CN101355583B (en) 2012-05-23

Family

ID=40308171

Family Applications (1)

Application Number Title Priority Date Filing Date
CN2008101960417A Expired - Fee Related CN101355583B (en) 2008-09-11 2008-09-11 Method for searching buffer based on loose location dependence in wireless self-networking

Country Status (1)

Country Link
CN (1) CN101355583B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018090255A1 (en) 2016-11-16 2018-05-24 华为技术有限公司 Memory access technique

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1278977A (en) * 1997-09-04 2001-01-03 艾利森电话股份有限公司 Method and arrangement for finding information
CN1736061A (en) * 2003-01-10 2006-02-15 皇家飞利浦电子股份有限公司 Dynamic network formation for wireless adhoc networks

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1278977A (en) * 1997-09-04 2001-01-03 艾利森电话股份有限公司 Method and arrangement for finding information
CN1736061A (en) * 2003-01-10 2006-02-15 皇家飞利浦电子股份有限公司 Dynamic network formation for wireless adhoc networks

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
JP特开2006-237666A 2006.09.07
袁繁华等.移动自组网的一种启发式地理位置路由协议.《福建电脑》.2007,(第6期),87-88. *

Also Published As

Publication number Publication date
CN101355583A (en) 2009-01-28

Similar Documents

Publication Publication Date Title
CN102810118B (en) A kind of change weighs net K nearest neighbor search method
US10324913B2 (en) Creating and using access zones for delivering content
CN1642144B (en) Information dissemination method and system for mobile wireless ad hoc networks
RU2419255C2 (en) Method to detect physical location of mobile phone at this time
US20070167173A1 (en) Generating and dynamically updating databases of WIFI hotspots locations and performance metrics via location mappers
CN102355490B (en) Spatial information cluster cache pre-fetching method for network spatial information service system
CN101355473B (en) Method for publishing and searching mobile self-networking resource as well as mobile self-networking network node equipment
CN101369982A (en) Method for data packet greedy forwarding in vehicle-mounted Ad hoc network
CN102348160A (en) Multimode signal-based positioning method, system and positioning platform
CN101900565A (en) Path determining method and device
CN109413661A (en) A kind of computer installation away from method and device
CN102968499A (en) Device for providing traffic information inquiry service, traffic information inquiry method, and system for providing traffic information inquiry service
CN103020130A (en) k nearest neighbor query method oriented to support area in LBS (Location-based Service) of urban road network
US20160076901A1 (en) Method and apparatus of computing location of safe exit for moving range query in road network
Aissaoui et al. Hcbls: A hierarchical cluster-based location service in urban environment
CN101394353A (en) Data packet competition forwarding method used in vehicle-mounted Ad hoc network
CN101207880A (en) Mobile phone indicating guidance system based on server client machine mode
Zheng et al. On semantic caching and query scheduling for mobile nearest-neighbor search
CN101355583B (en) Method for searching buffer based on loose location dependence in wireless self-networking
Ku et al. Nearest neighbor queries with peer-to-peer data sharing in mobile environments
CN104581633A (en) Region nearest neighbor inquiry system and method supporting privacy protection in obstacle space
Park Efficient data access for location-dependent spatial queries
Han et al. Hierarchical location caching scheme for mobile object tracking in the internet of things
Bordogna et al. Managing uncertainty in location-based queries
Park et al. Adaptive data dissemination schemes for location-aware mobile services

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C10 Entry into substantive examination
SE01 Entry into force of request for substantive examination
C14 Grant of patent or utility model
GR01 Patent grant
C17 Cessation of patent right
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20120523

Termination date: 20130911