ns2 project in Montana

         ns2 project in Montana metrics corresponding to the PDES, transaction and activity

levels within the diagnosis, will be examined in the

next point, in order to identify the critical transactions and

the critical activities within them, and to ns2 project in Montana evaluate the causes

of their behavior. The PDES level metrics in the PDES

analysis window are shown. Upro is the global utilization

of the set of processors in the window,ns2 project in Montana and the rest of metrics

are mean values for the set of transactions . A significant

synchronization load from the relative value of the

waiting time can be observed. A very low rate of failures

and a medium level utilization of the set of processors are

also observed. In Figure 10 the utilization of each processor

in the three possible windows (PDES, transaction and

activity) is shown. Processor 0 is seen ns2 project in Montana to be saturated. Parameters

show that the host tasks are mapped in this processor.

Finally, Table 8 shows the incidence of the causes of

behaviour for whole PDES as a whole. Here, blocking is

the most important cause of behaviour. In Figure 11 the relative value of ns2 project in Montana transaction response

times with regard to their deadlines is shown. Only

transaction 0 in its transaction window exceeds its deadline.

The metrics represented in Figure 12 permit several conclusions:

constraint of productivity absorption is fulfilled

because all the theoretical responses have been produced;

deadline constraint in transaction 0 is not fulfilled because

there are failures; and finally the variability of the response

time is lower than 0.1 only in transaction 15. According

to the information provided by the metrics and the ns2 project in Montana rules for

this stage, transaction 0 is selected as a general Tables 9 and 10 show the incidence of the causes

of specific behaviour (transaction window) and general behaviour

(PDES window) for critical transaction 0, respectively.

Both blocking and processing have the same incidence

in general behaviour, while processing has double incidence

in specific behaviour. As the number of deadline

failures is very small, the causes of specific behaviour are more useful than those of general behaviour for design improvement.

Activity level metrics considered here ns2 project in Montana correspond

to activities composing the critical transaction 0. The

metrics refer to activity and PDES windows, but the analysis

is centered on the former, which is more representative

of deadline failures in this case. In Figure 13 the relative

value of each activity response ns2 project in Montana time with respect to

the transaction response time is shown. Activity 1 is seen

to be the longest activity with nearly 40% incidence in the

transaction response time. The metrics also confirm that the

variability in activity 1 exceeds 0.1. According to the information

provided by the metrics and the rules for this stage,

activity 1 is selected as a general critical activity.  In Figure 14 the relative value of thewaiting time

of each activity with respect to its response time is shown.

In critical activity 1 the waiting time represents only 5% of

the response time, the other 95% corresponding to the service

time. Tables 11 and 12 show the causes of the specific

behaviour (activity window) and ns2 project in Montana general behavior of critical activity 1, respectively. Table 11 also

shows the partial incidences of each diagnosis level. The

main causes of specific behaviour are two: a) contention

with other activities of equal priority (the corresponding activities

[i,1] in the other transactions) ns2 project in Montana supported by different

tasks; and b) code execution. Both of these occur during

service time. In Table 12 processing ns2 project in Montana during service time is

found to be the cause of general behaviour with almost total

ns2 project in Illinois

        ns2 project in Illinois the Host interface is implemented with four tasks: inport,

outport, inmsg and outmsg. Inport receives packets

from the host. If the packet is a control packet, it is sent

to inmsg. If it is an ACK or a NAK, it is sent to ns2 project in Illinois outmsg.

Outport receives packets from outmsg and inmsg and sends

them to the host. Inmsg receives control ns2 project in Illinois packets from inport.

If the packet is not valid, it sends NAK to the host

through outport. If it is valid, it sends ACK to the host

through outport and the new interval to the ns2 project in Illinois motor task.

Outmsg receives speeds from the motor tasks and ACKs

and NAKs from inport. All of them are sent to the host.

The host has three tasks. phost is the main ns2 project in Illinois task and

phostin and phostout are input and output tasks for communication

with their corresponding tasks in the RSS host

interface. The embedded system was implemented in a

PARSYS SN9500 machine, a distributed memory parallel

machine based on Transputers with 8 ns2 project in Illinois processors. In this

machine the task communications are established through a

virtual channel network. RSS tasks were implemented over

4 processors. For simplicity in the case study, host tasks

were also implemented in the same ns2 project in Illinois machine using an extra

processor. According to the methodology, the relevant actionreaction

event couples which demand system responsemust

first be identified. The action events are the periodic

requests for speed-reading from the ns2 project in Illinois motor tasks to the

tacometer task. The reaction events are the arrivals at

outmsg task of ACKs coming from the host in response

to the emission of packets with speed data. A total of 16

kinds of events, one per motor, are considered. The transactions

or sequences of activities to be executed as system

responses to these events include all the ns2 project in Illinois activities executed

from the speed-reading request to the ACK reception from

the host. All 16 transactions considered ns2 project in Illinois in the analysis have

the same structure, as shown in Figure 9, corresponding to

the PDES behavioural model. he real-time constraints of each transaction in the case

study depend on the speed of the corresponding motor. The

deadline of each transaction has the same ns2 project in Illinois value as its period

of execution, as shown in Table 5, where Tra refers to the

transaction index and time is given in milliseconds. At this point, parameters and metrics considered in the

methodology are examined in order to check the temporal

behaviour of the system, give a diagnosis and proceed to

possible design improvements. Load ns2 project in Illinois parameters correspond to the periods of transactions.

Table 6 resumes the rest of the parameters: parameters of

the structural model, parameters of the behavioural model

and parameters of connection between the models. It shows

the mapping of tasks in processors, ns2 project in Illinois the mapping of activities

in the tasks and the number of blocks giving support to

the activities (Nb). Index i refers to transactions and activities

[i,1] are the only ones supported ns2 project in Illinois in various independent

blocks and tasks.

ns2 project in Isle of Man

     ns2 project in Isle of Man the goal of configuration can be either the

fulfillment of the real-time constraints using the available

resources, or the reduction of resources in the PDES design,

while maintaining the fulfillment of the real-time constraints.

In Table 3 the design alternatives for ns2 project in Isle of Man configuration are

described. In Table 4, the proper design alternatives for each, The case study considered here to show the use of the

analysis methodology has been widely ns2 project in Isle of Man studied in several

papers, such as A Remote Speed Sensor (RSS) measures the speed of a

number of motors, and reports them to a remote host computer.

The speed of each motor is obtained by periodically

reading a corresponding digital tacometer. The interval between

speed readings (10-1000 ms.) for each motor is specified

by the host computer. An Analog to Digital Converter (ADC) with a set of multiplexed

channels is used to measure the speed signal provided

by tacometers coupled to the motors. The ADC accepts

reading-requests in the form of ns2 project in Isle of Man motor numbers (integers

in the range of 0–15). After a request has been received,

the converter reads the speed of the motor, stores it

in a hardware buffer, and generates an interrupt. The converter

can only read the speed of one motor at a time.

The interval between readings for a given motor is specified

in a control packet which is sent from the host computer

to the RSS. The speed of a motor is reported to the

host via a data packet. When a control packet is received

from the host, it is checked for ns2 project in Isle of Man validity. If the message is

valid, an acknowledgment (ACK) is sent to the host. If it

is not, a ns2 project in Isle of Man negative acknowledgment (NAK) is sent. When a

data packet is sent, the RSS waits to receive either an ACK

or a NAK from the host. If a NAK is received, or neither an ACK nor a NAK is received within half the reading interval, the message emission is marked as a failure The design ns2 project in Isle of Man structure of the case study has four principal parts: the tacometer, the motors, the host interface and the host. Each of these parts is composed of one or more

software tasks, as seen  The tacometer task can access the speeds of all the motors and is constantly waiting to read requests. When a request is received, it reads the corresponding ns2 project in Isle of Man speed and sends

the data to themotor task. Motor tasks, one per ns2 project in Isle of Man motor, periodically send the reading-requests to the tacometer task. Once data is received, it is filtered and sent to the host. These tasks have

associated tasks which inform them about new reading intervals ns2 project in Isle of Man requested from the host.

ns2 project in uttarakhand

   ns2 project in uttarakhand finally, the Index of concurrence (Ic) provides information

about the level of concurrence of all the activities

composing the transaction in a given instance. This index

was derived from another similar metric successfully used

in In this point, four aspects of the diagnosis are outlined:

the stages to follow in the diagnosis, the causes of the behaviour

considered, the support provided by ns2 project in uttarakhand parameters and

metrics, and finally, the identification of the critical components

of the behavioural model. Diagnosis ns2 project in uttarakhand of the PDES. In this first stage, global

causes of behaviour of the set of transactions in ns2 project in uttarakhand the behavioural

model are evaluated . Identification of critical transactions. The objective

of this stage is the identification of transactions which

do not fulfill one or more of the real-time constraints defined

in the specification of behaviour. Diagnosis of each critical transaction. In this

stage , the causes of behaviour which explain the response

time of each critical transaction are found. Identification of critical activities.The objective

of this stage is the identification of the most significant or

critical activities (bottlenecks) in each critical transaction. Diagnosis ns2 project in uttarakhand of each critical activity. In this last

stage, the causes of behaviour which explain the response

time of each critical activity are found. When considering the causes of temporal behaviour in the

diagnosis, the differences between the causes at activity level and the causes at transaction and PDES levels must

be clearly established. At activity level, the causes of behaviour ns2 project in uttarakhand  correspond to the temporal components of the response time of the critical activities. Three levels of diagnosis are considered. The first level of diagnosis evaluates the waiting and service times of each activity. Evaluation of communication and blocking times during waiting time, processing during service time and resource contention during ns2 project in uttarakhand both waiting and service times, correspond to the second level of diagnosis. Finally, the third level of diagnosis evaluates the specific components of communication, processing, blocking and contention times. Based on these three diagnosis levels,

a set of causes of temporal behaviour of the critical activities can ns2 project in uttarakhand be established. Figure 7 represents the three levels

of diagnosis all the causes considered, with a brief description of each, are detailed.

At PDES level, the causes of behaviour of the PDES as

a whole must be found, whereas at transaction level, the response ns2 project in uttarakhand

time of critical transactions must be explained. To

achieve those objectives, the aggregation of transaction and

activity metrics are considered respectively. Therefore it is

not possible to distinguish all the causes of behaviour considered

at activity level. Only the first two levels of diagnosis

are considered, and ns2 project in uttarakhand so the causes of behaviour are reduced

to five. These causes are shown in Table 2. The first

cause in this table is only valid at the PDES level, while

the other four are valid at both PDES and transaction levels.

The third cause, WAI BLO, also includes contention.

The incidence of each cause of behaviour is evaluated

with a value in the range of 0–1. This value of incidence is

the product of the partial incidence values obtained at each

level of diagnosis. Once the ns2 project in uttarakhand incidence of the causes of the behaviour of each

critical activity composing the critical transactions has been

established, those with high incidence will be considered,

in order to tune the PDES design and establish its proper

configuration.

ns2 project in tamil nadu

 ns2 project in tamil nadu the PDES window is obtained from the PDES basic period

Tpdes, which corresponds to the Least Common Multiple

(LCM) of all the periods Ti specified for the periodic

transactions, as seen in Figure 5. This approach was also ns2 project in tamil nadu

used in [14] and [3]. The first PDES period in the execution

must be considered as PDES window ns2 project in tamil nadu if the transient

behaviour caused by pipelining [3] is being analyzed. On

the other hand, to analyze the permanent behaviour, several

PDES basic periods, starting with the second, must be considered

in the PDES window. The number of PDES basic periods in the PDES window increase with the variability of

the response times in the transactions and the mean activation period of the aperiodic transactions Parameters represent all the known information about

the PDES before execution. So, while they give only a

static view of the system, they are necessary to determine

the influence of the design components ns2 project in tamil nadu on the behaviour of

the system. Four kinds of parameters are considered in the

methodology: load parameters, parameters of the structural

model, parameters of the behavioural model, ns2 project in tamil nadu and parameters

of connection between models. Load parameters define the demands of service on the

system from the environment, and reflect ns2 project in tamil nadu the load characteristics

of transactions in the PDES behavioural model.

The structural model defines the current design of the

PDES and considers components on four ns2 project in tamil nadu levels or layers:

the whole PDES, processors, tasks (scheduling units) and

blocks. execution of activities. The behavioural model, on the other

hand, considers components on three levels: the PDES as a

whole, transactions and activities. Figure 6 shows the levels

considered in each model and the relationships between

The parameters of the structural and behavioural models

represent mapping relationships between their components

in the levels of the corresponding model. Finally, the ns2 project in tamil nadu parameters

of connection between the models establish the

mapping of activities in blocks, providing the basis with

which to relate both models. Metrics are the criteria to explain the behaviour observed

in the system. They can be simple measurements obtained

from the event trace, relationships between the measurements

and the parameters, resource utilization ns2 project in tamil nadu or special indexes.

Metrics provide information which feed the models

corresponding to both the behavioural and resource views.

The metrics used in this methodology can be classified

according to the level of analysis in which they are applied.

So, three different levels can be distinguished: PDES level

metrics, transaction level metrics and ns2 project in tamil nadu  activity level metrics.

For a specific level of analysis and a specific view, the

metrics can be calculated using all three analysis windows,

that is the PDES window (Wpdes), the transaction window

(Wtra) and the activity window (Wact). Three special indexes correspond to important metrics in

the resource view. The Index of blocking (Ib) helps to identify

the cause of blocking time in an activity. This index ns2 project in tamil nadu

compares the activity response time with the transaction period,

in order to establish if the blocking time is caused by

execution overlapping of transaction ns2 project in tamil nadu instances. Therefore,

index values over 1 indicate overlapping. The Index of parallelism

(Ip) provides information about the level of concurrence

of activities executed in parallel within a transaction

instance.

ns2 project in rajasthan

ns2 project in rajasthan the most typical transactions in a PDES respond to periodic

events and, consequently, are characterized by a periodic

execution. These are called periodic transactions.

Transactions responding to aperiodic ns2 project in rajasthan events are called aperiodic

transactions. The period of activation Ti is the main load characteristic for periodic transactions, while the mean

activation period MTi and the typical deviation of it DTi

characterize aperiodic transactions. The timing constraints ns2 project in rajasthan for both periodic and aperiodic

transactions are derived from the performance specification

of the PDES. These are absorption of productivity (capacity of the PDES to respond to all the input events produced during execution, see [10]) and deadline Di In the context of this research work, a full ns2 project in rajasthan software monitor for a distributed memory parallel architecture based on T9000 transputers was developed [21]. In Figure 3 the instrumentation of one activity is shown. This monitor is nowadays being ported to distributed systems based on

POSIX. The function of the monitor is to trace the occurrence of the ns2 project in rajasthan most relevant software events during an application execution, and to store information related to them in a set of trace files. So, the functionality of the monitoring system consists of run-time events (communications, synchronization operations, I/O operations, etc.), transaction event  (start) and activity events (ready, begin and end). The monitor is ns2 project in rajasthan structured in three main components: a set of distributed monitoring processes, a collection of ns2 project in rajasthan instrumentation probes spread over the application processes, and one instrumentation data structure per application task.

This methodology allows the analysis of system behaviour

at three possible levels of abstraction. The first level

considers the analysis of the PDES as a whole, ns2 project in rajasthan considering

aggregated information of all the transactions. The second

level considers the ns2 project in rajasthan analysis of each transaction ns2 project in rajasthan of the

PDES, paying more attention to the critical ones. Finally,

the third level considers the analysis of each of the activities

in the transactions. This multi-level character permits a

top-down approach in thens2 project in rajasthan  analysis very useful in finding the

behavioural problems of the PDES.

Figure 4 resumes the steps carried out during the analysis

process. Starting from the event trace obtained by

the monitor after PDES execution, an X-window tool permits

the validation of the trace according to the behavioural

model and generates the parameter ns2 project in rajasthan and metric values. From these values, the diagnosis process is carried out, checking the fulfillment of the real-time constraints and obtaining

the causes of behaviour of the PDES. Finally, with the

causes of behaviour, parameters ns2 project in rajasthan and metrics, the configuration

process suggests design alternatives for ns2 project in rajasthan behaviour improvement. According to the multi-level analysis character described above, the methodology considers three possible analysis windows:

1. PDES Window: a temporal window long enough to

represent all the ns2 project in rajasthan system behaviour characteristics for

the scenario under analysis. 2. Transaction Window: which corresponds to the

longest response interval of a transaction within the

PDES window. Activity Window: which ns2 project in rajasthan corresponds to the response

interval of an activity within the transaction window.

ns2 project in punjab

    ns2 project in Punjab in the model, three principal times are associated to each

one of these activities: Waiting Time (the time between the

time-stamps of its ready and begin events), Service Time

(the time between the time-stamps of its ns2 project in punjab  begin and end

events) and Response Time (the sum of Waiting and Service

Times). The behavioural model presented here is useful to represent

sequences of activities developed ns2 project in punjab in response to the

main input events which the PDES must deal with, and

so is useful for the analysis methodology to be presented.

These sequences are called end-to-end transactions or simply

transactions in the methodology. Construction of the ns2 project in punjab  behavioural model implies a deep

understanding of another two models defined by the

methodology used in the development of the PDES: the

functional model, built from the ns2 project in punjab  specifications, that represents

the main activities of the system to be developed, and

the structural model, that represents the ns2 project in punjab proposed design to

support the functionality. From these two models, all the

sequences of activities that conform the behavioural model

can be derived. The goal of the methodology is performance debugging

of PDES. To achieve this, the analysis of system behaviour

from the early design phase to its final implementationmust

be provided. Thus, the methodology involves the construction

of a synthetic prototype [15] of the PDES design, which

is analyzed and refined until fulfillment ns2 project in punjab of the timing constraints

is achieved.

The prototype also serves as a skeleton

for the implementation phase. In Figure 2 the integration of

the methodology in the PDES development cycle is shown.

Two refining cycles can be derived from the methodology;

one working with early designs ns2 project in punjab through prototypes of the

PDES, and the other with the implementation of the PDES.

The methodology approach can be resumed in the following steps:

1. Prototyping of the initial PDES design under analysis.

2. Understanding of the sequences of activities to be executed

as responses to input events (transactions), establishing

a specification of behaviour for them.

3. Instrumentation of the PDES software prototype to

enable the monitoring system to ns2 project in punjab obtain information

about the behaviour of transactions during the PDES

execution. 4. Execution of the instrumented PDES under specific

operational conditions (scenario) over a period of time

long enough to obtain a representative event trace.

5. Checking of the fulfillment of the real-time constraints

defined in the specification of behaviour for the PDES Development of a multi-level analysis in specific temporal

intervals (analysis windows) based on a set of

parameters and metrics derived from ns2 project in punjab the trace, and

combining structural, behavioural and resource views.

7. Identification of critical transactions which do not fulfill

their specifications of behaviour, and evaluation of

the incidence of a set of possible causes of the behaviour

observed in the PDES as a whole, the critical

transactions and the critical activities within them (diagnosis

of temporal behaviour). 8. Tuning of the system design according to the incidence

of each cause of behaviour, establishing a ns2 project in punjab suitable configuration

of the PDES. 9. Repetition of the analysis cycle until a final prototype,

which achieves fulfillment of the timing constraints

with minimum amount of resources, is obtained.

10. Implementation of PDES design and repetition of the

analysis cycle until its final implementation. The specification ns2 project in punjab of behaviour of the PDES consists of

specifications of the behaviour of ns2 project in punjab each transaction. These

specifications consider load characteristics and timing constraints

in transactions.

ns2 project in Quebec

ns2 project in Quebeca  data or control

dependency exists between the successive tasks, which imposes ns2 project in Quebec a precedence requirement on their scheduling. The sequences of tasks may span multiple processors and one simple task can belong to more than one end-to-end task. Tasks are the units of scheduling in the computational model,ns2 project in Quebec but they are not the only components of the model.

In fact, because we consider the possibility of a certain level of complexity in the tasks, we also consider the blocks of code executed within the tasks in the computational model. In the ns2 project in Quebec simplest case, only one block of code corresponds to the whole code of one task. The existence of computational units ns2 project in Quebec within the task in our model will also permit the construction of a more detailed behavioural

model to support the analysis of end-to-end tasks, as will be shown below.

The analysis of the behaviour ns2 project in Quebec of the end-to-end transactions

is supported by a behavioural model that clearly explains

the way the sequences of activities take place.

To describe the temporal ns2 project in Quebec behaviour of PDES in terms

of events, delays and actions, several approaches or be- havioural models can be employed: models based on eventordering graphs such as execution graphs [18] and Petri

Nets [11]; structured models based on state machines such

as the control flow of Hatley and Pirbai [5]; and models

based on process ns2 project in Quebec algebras such as CSP [6]. A model based

on an event-ordering graph has been selected as the behavioural

model for this research work. The selection was

made as a result of its simplicity and wide applicability.

The model is composed of two main elements [23]: 1)

Activities, which are represented by ns2 project in Quebec a sequence of three

events: Ready, when the activity is ready to start; Begin,

when it starts; and End, when it finishes; and 2) A set

of precedence and synchronization relationships defined on

the ready and end events, which ns2 project in Quebec establish partial ordering

for a group of activities. These relationships give rise to

the kinds of activities represented in Figure 1. SEQuence

implies chains of communicating activities in a transaction.

SYNchronization implies activities ns2 project in Quebec that also communicate

with activities belonging to other transactions. ALTernation

implies a group of alternative activities in a transaction (supported

by blocks in the same or different tasks) where only

one activity has place on each instance of the transaction.

REPlication implies the same ns2 project in Quebec  order as ALTernation, but in

this case the activities are replicas (activities with the same

function and code) useful to increase the throughput of the

transaction. Finally, PARallel implies activities in a transaction, developed in

parallel in different processors.

Ns2 project in Madhya pradesh

    ns2 project in Madhya Pradesh there may exist multiple paths between

a pair of source and destination nodes in the positive

gather-scatter tree. How to ns2 project in Madhya pradesh choose from these paths

to reduce the communication latency is a difficult problem.

Mainly, we need a good heuristic to balance the communication

load (number of transmitted blocks) on each link in

a phase. We have derived the routing on ns2 project in Madhya pradesh the positive gatherscatter

tree; routing on the negative tree can be similarly

obtained. To perform complete exchange, one naive solution

is to sequentially perform the positive phases followed

by the negative phases. Apparently, this is inefficient as

half of the links will be unused in each phase. We propose ns2 project in Madhya pradesh in this paper a measurement based methodology

for performance debugging of complex and noncritical

embedded systems with end-to-end deadlines. The

methodology considers an initial design for the ns2 project in Madhya pradesh embedded

system, which is the result of using a suitable design

methodology for this kind of systems [9]. After building

a system prototype based on the initial design and carrying

out measurements during its execution, the ns2 project in Madhya pradesh methodology

permits not only the embedded system to be checked

in practice, but also the identification of a set of causes of

the observed system behaviour. Knowledge of ns2 project in Madhya pradesh these causes

can also help in refining the design parameters (i.e. task

priorities and mapping) when the timing constraints for the

system are not fulfilled. The methodology is supported by metrics corresponding

to three system views , which are behavioural, structural

and resource views. The structural view is a static

view of the system and provides information ns2 project in Madhya pradesh about the software

structure and its mapping on hardware. The resource

view provides dynamic information about the use of the resources, The last view, the behavioural view, provides information about the temporal behaviour of the system in terms

of sequences of activities carried out in the system.

The organization of the rest of the paper is as follows:

section 2 presents the computational model of the kind of ns2 project in Madhya pradesh

embedded systems to which the performance debugging

methodology is oriented; in section 3 the model used in

the behavioural view is shown; section 4 presents the main

steps and aspects of the methodology; in section 5 the performance

of a well-known case study is debugged using the

methodology; finally, in stage 6 the conclusions and future

work are presented. The methodology is applied to parallel

and distributed embedded systems, hereafter ns2 project in Madhya pradesh referred to

PDES. The embedded applications supported by the methodology

are composed of sequences of tasks, called end-to-end

tasks. These tasks are executed in order to give response to

input events in the system (internal clock signals or external ns2 project in Madhya pradesh signals from the transducers), generating the corresponding output events (signals for the actuators).

ns2 project in lakshadweep

    ns2 project in lakshadweep the basic component objects of the lift system is

the buttons on the floors or inside the lifts. Buttons

have a common behaviour; they can be pushed On

by people and turned Off by the system. The projection symbol ns2 project in lakshadweep indicates visibility, i.e.

introduces the list of those features (local schema)

which are accessible via the dot notation. If the list is omitted, as in previous examples, all features are

visible. In the class Lift, the attribute fbuts (floor buttons)

models the panel of floor buttons where the ns2 project in lakshadweep index of

the sequence models the floor numbers. The attribute

md and ds models the move direction status and liftdoor

status. The attribute current models the floor

position where the lift is currently at. The attribute

extGoal represents an external request ns2 project in lakshadweep which is assigned

to the lift as a temporary destination. Inside a lift, a floor button can be selected by people.

This action is modelled by operation SelectFloor.

Note that the notation operation1 operation2 denotes ns2 project in lakshadweep

environment enrichment in that the schema

text of operation1 enriches the environment in which

operation2 is interpreted. This environment enrichment

frame also can used to model multiple concurrent

operation interactions. The lift door can ns2 project in lakshadweep be opened  and closed.

There are two kinds of move operations: one

is driven by the external request (MoveToExtGoal),

the other is driven by the internal request . The lift move direction is dominated

by the external request (if it has been assigned

to the lift) rather than the internal request. This is ns2 project in lakshadweep

ensured by the precondition extGoal = @ of the operation

1. The system safety property (S), “The lift door must

be closed before any movement (Up or Down),” is

ensured by the predicate ds  Closed in the preconditions

of both the operation MoveToExtGoal and

MoveToIntGoal. Also, as preconditions of both the

operation MoveToExtGoal and MoveToIntGoal requires

that there is an external and/or internal ns2 project in lakshadweep request,

therefore the system property (Pl), “When a

lift has no request, it should remain at its final destination”,

is ensured. The 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”, is also captured in the

definition of the operation MoveToExtGoal. As the definition of some operations ToOpenDoor,

MoveToExtGoal and MoveToIntGoal are relatively

complex, to improve the understandability of the

model, we present a finite state machine diagram Figure

2 to highlight the essential behaviour of the lift. Because the main characteristic states of the lift are

the move direction and the door status. A permutation of ns2 project in lakshadweep the cross state space of MoveDzrectzon and

DoorStatus forms the states of the finite state machine

for the lift. Transactions between states are labelled

with Object-Z operations with instantiated preconditions.

The instantiated preconditions for each ns2 project in lakshadweep operations

are also partitioned and labelled so that they

can be presented in a reusable fashion. We believe this

improves the readability of the finite state machine diagram

for a complex system.