ns2 project in kerala

     ns2 project in kerala the remaining two schemas are operation schemas.

Operation schemas have a A-list of those attributes

whose values may change. By convention, no Alist

means no attribute changes value. Every operation ns2 project in kerala

schema implicitly includes the state schema in

un-primed form ,Operation ns2 project in kerala Leaveoutputs a value item! defined as the head of sequence

items and reduces items to the tail of its original value A history invariant is an optional predicate over histories

of objects of the class expressed in temporal logic.

Such predicates further constrain possible behaviour.

For example, suppose we wish to specify in the generic

queue that whenever Leave or Delete is continuously

enabled it must eventually occur. Objects ns2 project in kerala may have object references as attributes] i . 9

conceptually, an object may have constituent objects.

Such references may either be individually named or

occur in aggregates. For example, the declaration, C declares c to be a reference to an object of the class

described by C. A declaration c, d : C need not mean

that c and d reference distinct objects. If the ns2 project in kerala intention

is that they do so at all times, then the predicate c d

would be included in the class invariant.

The term c.att denotes the value of attribute att

of the object referenced by c, and c.Op denotes the

evolution of the object according to the ns2 project in kerala definition of

Op in the class C, A lift system for an multi-floor building consist of

multiple elevators. Inside the elevator there is a ns2 project in kerala panel

of floor buttons each of which indicates a destination

floor. Outside the elevator there are two direction ns2 project in kerala buttons

on each floor which call for service, one for up and

the other for down (except the first floor and ns2 project in kerala the top

floor on which only one button is needed). Any button

can be pushed at any time. Any external floor

button will be on from the time it is pushed until the

elevator with the same travel direction stops at the

floor and opens the door. Any internal ‘on’ button of

a lift will be turned off when the lift visits the corresponding

floor. safety property (S): The lift door must be closed

before any movement (Up or Down).

system property (Pl): When a lift has no ns2 project in kerala request,

it should remain at its final destination.

system property (P2): The lift has to satisfy an

external floor request only if it goes in the same

direction or if the request is the external destination

of the lift. system property (P3): When a request arrives

from a floor the system will put the request at

the end of the external request queue.

system property (P4): If an external request in

the queue is serviced by some lift on the way Up

or Down, then this request should be removed

from the request queue. temporal property (Tl): whenever there are some

idle lifts and the external service queue is not empty, ns2 project in kerala the longest waiting request is

removed from the queue and assigned to one idle lift as the temporal final destination. temporal property (T2): All request for lifts from floors must be serviced eventually. temporal property (T3): All internal requests for

lifts must be serviced eventually. temporal property (T4): If a lift’s door is open,

eventually it will be closed.

ns2 project in jharkhand

     ns2 project in jharkhand by separating the IDD layer as a distinct process

from the rest of the layers, any communication to the

IDD layer can be done asynchronously. Requests for

I/O on a given host will be controlled by the IDD process

on that host. Furthermore, all 1/0 ns2 project in jharkhand requests can

be made non-blocking allowing the system to overlap

communication with 1/0 which, in lower-bandwidth

networks, results in great performance benefits.

In this section, we describe the ns2 project in jharkhand communication

strategies used during data access in VIP-FS. Three

strategies for data access have been incorporated into

VIP-FS: direct access, two-phase a.ccess, and assumed

requests. This will facilitate research ns2 project in jharkhand in data access

arid availability schemes – one of the primary objectibes

of the project. The direct access strategy is the traditional access

method used for parallel and distributed file systems.

In this scheme, every 1/0 request ns2 project in jharkhand is translated into

requests to the appropriate 1/0 device.

Each distributed application is composed of one or

more clients. The file syst,em services each client independently

of the others. There is no globally organized

access strategy as with the remaining two methods This scheme is used when each client obeys a

self-scheduled access pattern. distributed application perform

1/0 access with some global pattern, then it is

useful to employ a more efficient access strategy. l’he

two-phase access strategy has ns2 project in jharkhand been shown to provide

more consistent performance across a wider variety

of data distributions than direct access methods [7].

With two-phase access, all clients ns2 project in jharkhand access data approximately

simultaneously. The file system schedules access

so that data sotrage or retrieval from the devices follow a near optimal pattern with a reduction

in the total number of requests for the entire 1/0

operation. In a second stage, the data is buffered and

redistributed to conform with the data decomposition

used by the application (the target decomposition). The two-phase access strategy gains its effectiveness

by relying upon the existence (assumed) of a higher degree,

less congested interconnection networks between

clients versus the network used to access data to and

from the storage system; this is often the case in parallel

machines. However, in distributed systems, shared

media networks are commonly employed, and ns2 project in jharkhand the basis

for two-phase strategy’s improved performance is

lost. We have designed an alternative approach which

may significantly improve read performance by greatly

reducing the number of requests seen by each 1/0 device;

we call this the assumed-requests technique.

With assumed-requests, data decomposition information

is distributed to the IDD processes as part of

the file description information. Clients are assured

to make requests in a collective manner as in two phase access. That is, we assume a Single-Program-

Multiple-Data (SPMD) of computation. A one-to-one or many-to-one mapping is established from the set

of 1/0 devices to a subset of clients (the latter case

occurs when the number of 1/0 devices exceeds the

number of clients). We say that the members ns2 project in jharkhand of the subset are asszgned to the 1/0 devices.

When a read operation is performed by the application

program, only the assigned clients have their requests actually delivered to 1/0 devices. ‘Thus, each

1/0 device only receives a single request each. From the ns2 project in jharkhand  request the 1/0 device receives, along with data decomposition information, each 1/0 device computes bhe amount of data required by all clients (itssigned or not).

Ns2 project in himachal pradesh

     Ns2 project in himachal Pradesh the comple.;i:y involved doing this is ofteri riianitgeahlr~a, rid lrbriiries have been developed to assist programmers in performing such decompositions. The way in which a parallel file is distributed among

disks can likewise be viewed in terms of a data decomposition

mapping. This map is maintained by VIP-FS

to allow transparent access to parallel files.

The situation becomes much more complex when

a distributed application wishes to ns2 project in himachal pradesh perform 1/0 operations

in a distributed manner. In this case, the host location and local address of each distributed element

has to be mapped to disk location, file, and an

offset within the local file. This map ns2 project in himachal pradesh will change for

every data decomposition, number of computational

hosts, and number of disks employed by the applicat,

ion. Maintaining this mapping in a general way

for every application becomes a tremendous burden

for the programmer. Futher, any application which

is written to perform optimally for a given configuration

would require major revisions ns2 project in himachal pradesh whenever execution

under a different data decomposition or system configuration

is required. The mapping function from ns2 project in himachal pradesh the data element (on a

client) tto the 1/0 device element (disk offset) is broken

down into two different mapping functions, and

the composition defines the overall mapping. To use

mapped access, the programmer is required to define

the data decomposition mapping, and the parallel file

mapping to disk. (Alternatively, the programmer can

simply employ the parallel file default mapping). The

decomposition mapping information in ns2 project in himachal pradesh conimunicated

to the file system via a procedure call. Once the desired mappings have been declared access can be performed by each host using the standard Unix calls. VIP-FS will maintain thti: mappings in complet,e transparency. Array References The dataparallel programming model has emerged as the most popular ns2 project in himachal pradesh programming model for parallel and distributed applications. As a result, many languages have been designed to support such a programming model. Within the scientific computing community,

languages such as High Performaiice For  have been developed to facilitate

the migration of massive quantitiis of legacy Fortran applications t.o parallel and distributed environments.

A dataparallel interfa.ce to the parallel 1/0 syst.em ns2 project in himachal pradesh would greatly enhance the power of dataparallel languages.

In such a system, data could be viewed entirely as a data structure, commonly an array of some

sort. Performing parallel 1/0 operations on the array data would require merely reading or writ.ing the desired 1/0 instruction. By making use of the data decomposition information (previously declared), the file

system will transparently deliver only the appropriate

portion to the associated client. All three functional layers of VIP-FS could be combined,

along with the application, into a single ns2 project in himachal pradesh executing

process. The advantage of such an organization

would be that interlayer communication would

involve the use of intraprocess communication mechan.

isms (e.g., procedure calls) resulting in a reduction of

overhead versus the interprocess communication otherwise

necessary. This cost savings could be significant

depending upon the message passing library used.

Further, it would simplify message handling within the

entire distributed system. On the other hand, such a

design would have one serious ns2 project in himachal pradesh limitation. All 1/0 requests

on a given host would have to be controlled

and directed by the VIP-FS process (now also the application

process) on that host. This renders all 1/0

requests to be blocking calls, serializing them at t.he

Ns2 project in haryana

      Ns2 project in Haryana the IDD file descriptor for each file is returned to the

requesting VPF layer during the open call request; it

is an index into an array of file descriptors returned

when the IDD process makes an open call to the local

file system. The VPF layer provides ns2 project in haryana  distributed applications with

a single file image for every parallel file that is opened.

It’s key function is to enforce the mapping of the distributed

application’s (distributed) data domain ns2 project in haryanato the parallel file. It maintains the data structures necessary

to support the view of logical parallel file structures.

It manages pointers to each of the Unix files that comprise every parallel file. Requests to the file

system (in the parallel file view) will be translated into

requests to the IDD layer which are the custodians of

the Unix files comprising the parallel file. Response

data returned by ns2 project in haryana the IDD layer will be recomposed

into the necessary structure to satisfy the parallel view

prior to sending it to the interface layer above. aforementioned information is stored in the VPF layer

file descriptor table. The application interface provided to a parallel file

sjstem is a very important considmation. Most parallel

file systems only provide Unix-like access to the

file system This allows ns2 project in haryana for flexibility but

cnn become cumbersome to use. For exxnple, when

a distributed array is being used by the application,

tlie burden for maintaining a ns2 project in haryana mapping from the arrciy

to the parallel iile (not always trivial) is plated

siluarely on the programmer. This may easily result

code which sacrifices better performance for east’ of

ogramming. The function of the interface layer is to providr a I qical, structural view of the parallel file to the overlsying

application It will permit the application to

eiigage by working with the ns2 project in haryana  data structure that

i t is using, rather than b the f i l ab straction if it so

v,shes The interface laqcr itsdf US^ a parallel file

al,sl raction; it is responsitJle for trarislatmg each The interface layer of VIP-FS ,currently supports

tho types of I)arallr  file access tij the application

ccan\entional Unix-like ac( ess whew, by default, all

i1odes have equal ,tcc’ess to the entirrh pardlel file md

riiapped access. Fut urc ns2 project in haryana iinplemcnt ations will mi-lude

array access. Ye describe each of these helow VIP-FS providcs ac(ess to parallt4 files i n the con-

\! ntional Unix mariner using open, close, read,

writ e, Isee, etc calls When usiiig this interface,

c ‘icli host executing the application will have access to

tlie entire parallel file It is the ns2 project in haryana responsibility of the

iliogrammer to arllit rate md sc.hecIiilc host access to

i lie parallel fibs to ensure the d fwr c~rle sults art’ obtoined

A5 with linix first-comc,-iirst-scr\ed seiiimt

I ’S apply, In many distributed and parallel applications, parailelism

is obtained by using data decomposition.

ita is partitioned, usually equally, among the host,

computers and operated on conciirrently When data

ih partitioned for this purpose,ns2 project in haryana  some mapping is often

iiivolved. The mapping associates thv global posit ion

of each data elernmt isith a ns2 project in haryana host and a local address

011 that host, and vice kecsa.

ns2 project in gujarat

      ns2 project in Gujarat a key objective in designing VIP-FS is portability

If the file system is to be an extension to message passing

libraries, it must be portable across different libraries;

as such, the design must employ ns2 project in gujarat only features

which are common to most, if not all, message passing

libraries. Also, it must be capable of co-existing

with other (Unix based) data mariagment or network

file systems that may be employed Further, it must

\le capable of operating in ns2 project in gujarat heterogeneous distributed

system environments. the InterfaceItyer, the virtual parallel file (VPF) layer, and the

device driver (IDD) layer E’igure 1 illustrates

the logical configuration of VIP-FS The Interface layer provides a variety of file access

abstractions to the application program. For example,

I t may be a simple interface composed of standard

iinix open, close, read, write fiinclions ns2 project in gujarat Or, the file

system may accept, information describing the mapping

of a parallel file to a partitioned data doniain,

and transparently arbitrate access according to this

napping. The VPF layer defines ns2 project in gujarat and maintains a unified

global view of all file system components It pro\ides

1 he Interface layer with a single file image, allowing

each parallel file to be viewed as a single large file organized

as a sequential stream of bytes It achieves this

tiy organizing and coordinating access to the IIID’s

files in such a way that a global, ns2 project in gujarat parallel file is constructed

whose component stripes art’ composed of the

independent IDD files Any specification of a file offset

by the Interface layer is resolved by the VPF into

;in IDD address, file ID, and ID11 file offset

As shown, the IDD layer is built upon and conimuriicates

with the local host’s file system. It manages

each file as an independent non-parallel file and pro-

\ides a stateless abstraction to the VPF layer above ‘rhus, the IDD layer arts as the mediator betwemi the

local host file system and the VPF layer nication between layers within and across hosts is accomplished

through the use of message-passing library

primitives. In the following section ns2 project in gujarat we discuss the implementation

of VIP-FS. The discussion proceeds in a bottomup

manner, from the IDD layer to the Interface layer.

We begin with a brief description of the initialization

and configuration process. As ns2 project in gujarat  its primary function, the IDD layer is responsible

for communicating with the local file system and providing

a stateless interface to the VIP-FS layer. The

IDD layer is implemented in VIP-FS as a set of Unix

processes. The IDD supports a non-parallel (i.e., Unix stream)

view of files. It does not have knowledge of the logical

parallel file or of mapping functions; that is, it carries

no knowledge of how data is distributed among the

disk set or among the processors. All ns2 project in gujarat communication

with the IDD will take place through a icommunications

daemon. Requests will identify the requesting

taskid, the desired operation IDD processes receive file access requests from the

VPF layer in the form of messages sent through the

message-passing library being used. Requests can be

made for any of the standard Unix file ns2 project in gujarat access operations

such as open, close, read, write, etc.. The IDD

process performs the requested operatioii and sends

an appropriate response back to the ns2 project in gujarat VPF layer. The

IDD process has no notion of any global file space.

ns2 project in goa

ns2 project in goa recall that the match effort for base rules is distributed by

heuristically choosing a restriction attribute (RA) for

each rule. A restriction predicate on the RA restricts

the match effort per rule at each base rule processing

site, thereby distributing the work done in base rule

matching. To achieve this, the metarules are analyzed

at compile time to determine the restrictions on base

rules as follows. Base rule RAs are  ns2 project in goa chosen so that at each site, only

those instances are generated that are relevant to

each other with respect to the set of metarules. However, ns2 project in goa at the same time, we must ensure that

all possible instances are generated over all the

sites. The abovens2 project in goa  two goals may be difficult to satisfy

simultaneously. Generating relevant instances according

to the metarules may require ns2 project in goa generating more instances than in the ordinary case where we

use restriction predicates that divide the range of

each base rule RA according to the processing potential

of the sites, to get match time reductions

per rule and uniform completion times over all

sites. This is so, since the distribution of relevant

instances may not agree ns2 project in goa with that determined by

the algorithm that is only concerned with dividing

up the match effort over all sites. The PARADISER system is now operational with

base rule processing being fully distributed and

metarule processing being carried out at a single MRP.

Initial experiments have shown that for large data

sets, the BRPs perform well under dynamic load balancing

to compute base rule matches in parallel and reduces the match time thus allowing the system to

scale. However, the single site ns2 project in goa MRP emerges as a bot,-

We have begun work on distributing the metarule

processing as well. ns2 project in goa Our current effort is to provide

distributed metarule processing using the full distribution

(FDM) scheme. Our initial experiments point

to typical patterns in the behavior of a rule-based system

as execution progresses. One such pattern is that

after several cycles, only a few metarules are typically

active, since many of the base rules relevant to the

bulk of the metarules do not produce instances after

the first few cycles. Under the FDM scheme, each

metarule is assigned to a distinct processor. Thus, in

a realistic situation, many of the ns2 project in goa MRPs may be inactive.

We have developed protocols that detect whether

or not a particular MRP will be active at a given cycle.

It is then possible to distribute the processing

load of the active MRPs over all available MRPs, i.e.,

we use the resources of the ns2 project in goa inactive MRPs whenever

possible. The load distribution is based on the assumption

that at each cycle, the entire conflict set is available at every MRP, since they can all collect all

of the instances as they are broadc.ast by the BRPs.

Load distribution then reduces to following a protocol

that determines how active ns2 project in goa MRPs will claim the

resources of inactive ones, and then executing some

variant of a popular parallel join algorithm adapted

to our particular needs. In future work, we plan to conduct comparative

studies of the various approaches to distributed control

as detailed in this paper with actual implementations within the PARADISER architecture. We also

intend to explore alternative and useful control specifications of practical importance. In [9], a number

of PARULEL programs are studied and some prelirninary

ideas are presented on how ns2 project in goa to improve the expressivity

of the metarule construct of PARULEL. These

are important open problems that will be the focus of

future work.

ns2 project in delhi

    ns2 project in delhi for each metarule, designate an MRP. We assum that processors are available on demand. Otherwise,some processors will be chosen to processmultiple metarules.0 As ns2 project in delhiinstances are generated at each base rule processing(BRP) site, they are sent to the MRPsfor which they are relevant by first consulting theCMRT augmented with processing site information.0 As instances arrive at an MRP, they are processedby the two-phase algorithm described above, inpipeline fashion. When all instances have beenreceived, tokensns2 project in delhi representing the unredacted instances are reported back to the source BRPs o broadcast to all BRPs for firing. This dependson whether the database is fragmented or replicated.In our initial implementation, we use thelatter (broadcast) scheme, for simplicity.This achieves “redact-all-possible” metarule semantics.n This is deterministic and independent of ns2 project in delhi instance generation order and MRP processing order. Thismethod scales with respect to the metarules. Evenbetter performance may be extracted under some simplecompile time optimizations, e.g, suppressing thetransmission of “apparently relevant” instances whichdo not really have any possibility of matching the targetmetarule because of the presence of “inappropriate”constants. Such conditions canns2 project in delhi be determinedat cornpile tirne and incorporated into the mappingtables at each BRP that direct the flow of generatedinstances to the MRP, one for each metarule.The LPM scheme features a metarulens2 project in delhi processor ateach site, i.e., paired with each base rule processor.The scheme is outlined as follows.0 Each site runs a restricted version of a rule programin a BRP, as usual, as well as a “coupled”MRP, that processes instances as they are generatedusing the two-phase algorithm, in pipelinefashion.0 The scheme is optimistic in the following sense. Itrelies on the generation of instances at each sitesuch that a good fraction of redactions will takeplace by processing only the local instance D H ,i.e., remote ns2 project in delhiinstances will not be needed.0 The unredacted instances are passed on to a“global” MRP for a final global filtering phaseif needed. The global MRP also operates on thetwo-phase principle.0 All instances that remain after the global ns2 project in delhiMRPprocessing are broadcast back (their instance id’sare broadcast) so that each BRP can execute theRHS actions.0 Instead of %level hierarchy, a Log(P)-level hierarchyis also possible, where P is the number ofB RPs .This scheme can be implemented to exhibit, eitherdeterministic or non-deterministic rule execution,depending on whether instances are simply markedon redaction, but allowed to participate in further metarule matching, or they are actually deleted. Apossible worst-case scenario is that all the work maybe done at the global MRP, thus making the localMRPs sources of overhead rather than ns2 project in delhicontributingto speedup of the metarule matching process, The MGR scheme is similar to the LPM scheme in

that an MRP is located at each BRP. However, compile

time analysis is used to determine restrictions on

the base rules in such a way that instances generated

locally at each BRP are only ns2 project in delhithose that are mutually

relevant with respect to the matching of the metarules.

Of course, one must also guarantee completeness, i.e.,

all instances must be generated over all BRPs

ns2 project in chhattisgarh

      ns2 project in Chhattisgarh as noted above, all sites send rule instances to the MRP as they are generated. Rule instances are collected in a queue read by the MRP. ns2 project in Chhattisgarh When a site is done generating rule instances, it, puts a message SENTALL on the queue, and the MRP ns2 project in Chhattisgarh tracks the receiptof this message from all sites to determine when allinstances have been received. The basic job of theMRP is to report back to each of ns2 project in chhattisgarh the sites which ofthe instances generated by that site should be fired.To accomplish this, the MRP executes the procedure displayed in Figure 1. In the algorithm shown in Figure 1 , the DEQrJErJE operation in step 1 has the obvious meaning. In step 2, the function IS-FREE ns2 project in Chhattisgarh determines if the current instanceis a free instance according to the definition given earlier. If the current instance is free, the CONTINUE directive “short-circuits” the WHILE loop by skipping the remainder of the ns2 project in chhattisgarh body and returning to the top. This happens for free instances whic,h are not redactable. Otherwise, the algorithm proceeds to insert the current instance in the appropriate instance relation (IR) in step 3. In step 4, a new WF tree is created with the current instance at the root. The tree contains as many branches ns2 project in chhattisgarh as there are applicable metarules that may redact the current instance. Each branch contains all the LHS conditions of the metarule it, represents as lists of conditional expressions. The root and all the c,onditional expressions are hashed into appropriate HTBL structures for subsequent fastaccess.

           This is the action of the MAKE-WF-TREE In this section we outline various approaches to processing

metarules in a distributed setting. In early ns2 project in chhattisgarh experiments with PARADISER, the performance of

metarule processing using a single metarule processor (MRP) and several base rule processors (BRP) showed

that even when base rule processing was balanced, the metarule processing tends to be the bottleneck in overall

system performance. function. In step 5, the function FOUND-MATCH tests each branch of the WF tree for the current instance

by first propagating the constants in the current instance to each conditional expression, and then carrying

out a constrained search of the IRs to determine if the LHS of any relevant metarule is ns2 project in chhattisgarh satisfied. If any

branc.h is satisfied, the WF tree representing the current

instance is REDACTED, by destroying the WF

structure and removing the entry for the current instance

in its IR, as well as clearing all HTBL entries

resulting from the creation of the WF tree. The algorithm

then simply returns to the top of the WHILE

Otherwise, in step 6, the current instance is used to

index into all possible WF roots that may be satisfied

because of this instance. This set is computed using

the existing HTBLs. Constants ns2 project in chhattisgarh

are propagated from

the roots of each WF tree to its branc,hes, as well as

from the current instance. If matches are found by a

constrained search against the IRs, the corresponding

roots are redac.ted by removing the root instance from

its IR and deleting all HTBL entries in step

ns2 project in chandigarh

    ns2 project in Chandigarh since this is a metarule, a conditional expression is applied to instance relations as opposed to base relations. Each ns2 project in Chandigarh child node contains the conditions necessary for the corresponding conditional expression to be true, and a flag indicating whether it has been found true. The root node, ns2 project in Chandigarh  which represents the potentially redactable instance on the RHS, is trivially ns2 project in Chandigarh true, since only by receiving a complete instance could the WF structure be initialized; thus it does not appear in the list of conditional expressions.

     The ns2 project in Chandigarh structure is called a Wait-For structure, indicating that it is “waiting for” the instances necessary to redact the instance stored at itjs root. WF structures are accessed ns2 project in Chandigarh through hash tables, one for each rule. As an instance of some rule r arrives, it is hashed into the hash table HTBL(T) that is specific to . HTBL(r) holds pointers to the WF structures for each instance of T. The hash tables are created such that the corresponding ns2 project in Chandigarh hash functions are defined on the attributes relevant to metarule matching. An access-efficient ns2 project in Chandigarh representation of the metarules.

    This table holds information on the freeness of rule instances. A rule instance is free if the corresponding base rule does not appear on the RHSof any metarule. Thus, free instances will ns2 project in Chandigarh  never be subject to redaction, and are ignored by theMRP. The CMRT also contains information on the relevance of various rule instance classes tothe matching of each metarule in the user program.

ns2 project in arunachal pradesh

     ns2 project in arunachal Pradesh MRP matches all instances against the set of MRP reports back to appropriate sites which inmet arules. stances are ns2 project in arunachal Pradesh firable. Clearly, under the naive approach, the MRP cannot proceed until all instances have been received from all base rule matching sites. This synchronization ns2 project in arunachal Pradesh is strictly not necessary; in general, redactions may occur as soon as a metarule is mat,ched. Thus, base rule and metarule evaluations may be pipelined. This observation ns2 project in arunachal Pradesh motivaks the development of the centralized two-phase Match/Tag-Fire scheme in the rest of this section.

     The basic algorithm can be extended ns2 project in arunachal Pradesh to the distributed case as well. We outline various distributed schemes that may utilize t,he basic two-phase pipeline processing method in the next, section.  In the basic centralized version of tthe algorithm, all sites send their rule instance as they are generated to the MRP. The goal is to have the metarule processing at the MRP nearly completed by the time ns2 project in arunachal Pradesh  the last instance is received from the slowest site. This is called “two-phase rnetarule processing” There is one IR for each  rule in the rule program.

      The relation scheme for an IR is obtained by conjoining the schema of the relations referenced on the LHS of the rule. As instances of base rules are received by the MRP, they are stored in the ns2 project in arunachal Pradesh appropriate IR. For each instance received at the MRP, a structure is created to represent the set of all metarules that are capable of redacting that instance. This is ns2 project in arunachal Pradesh called a “Wait-For”structure, and can be viewed as a tree. The instance in question is at the root, and each child node represents the LHS ns2 project in arunachal Pradesh conditions of a relevant metarule, represented as a list of conditional expressions that appear in the metarule.