Ehtesham Zahoor
email: ehtesham.zahoor@loria.fr

Olivier Perrin
email: olivier.perrin@loria.fr

Claude Godart
email: claude.godart@loria.fr

An event-based reasoning approach to Web services monitoring

In this paper, we propose an event-based framework that allows to specify and reason about the monitoring properties during composition process execution. The proposed approach is highly expressive and allows to specify monitoring properties that can be based on either functional or nonfunctional requirements, allows multi-level detection of any violation, allows to calculate effects of any such violation on the overall process execution and to recover from it using a set of recovery actions. The choice of a reasoning based approach allows to foresee the effects of violations and respects any functional and non-functional constraints associated with the process, when performing recovery. In addition, as the approach builds upon an event-based declarative framework called DISC, it results in an integrated approach as both composition design and monitoring framework are event-based.

I. INTRODUCTION

Web services are in the mainstream of information technology and are paving way for inter and across organizational application integration. Individual services may need to be composed to form new added value processes and the need to monitor the Web services composition process during execution stems from two major objectives. At one hand continuously monitoring the resource utilization, SLA's violation, or some domain specific Key Performance Indicators (KPI's) may be required to measure the performance or to fulfill some domain specific monitoring requirements.

Then, as the Web services are autonomous and only expose their interfaces, composition process is based on design level service contracts and the actual execution of composition process may result in the violation of the design-level services contracts due to errors such as network or service failures, change in implementation or other unforeseen situation. This highlights the need to detect the errors and react accordingly to cater for them. The reaction may include to calculate the effect the violation has on the overall process execution and then to recover from it. Traditional approaches for the composition monitoring are proposed as an extension to some particular run-time and are tightly coupled and limited to it. In contrast the use of an event-based approach works on the message-level and thus is unobtrusive, independent of run-time and allows for integration of other systems and processes, as discussed in [START_REF] Moser | Event driven monitoring for service composition infrastructures[END_REF]. Then, the traditional monitoring approaches build upon composition frameworks that are highly procedural, such as BPEL, an this in-turn poses two major limitations. First, they limit the benefits of any event-based monitoring approach as the events are not first-class objects of the composition design framework (but rather defined and extracted from it) and functional and non-functional properties are not expressed in terms of events and their effects. Then, the use of procedural approach for process specification make it very difficult to use recovery actions such as re-planning or alternate path finding as we discussed in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. In this paper, we propose an event-based framework that allows to reason about the monitoring properties during execution. The proposed approach builds upon an event-based declarative framework, called DISC, and as both composition specification and monitoring framework are events based, this results in an integrated approach that is easily able to monitor, detect, calculate side effects and recover from the monitored violations. Specifically we make the following contributions that highlight the uniqueness of our approach:

Event-based monitoring: Event-based approach results in message-level monitoring approach that allows integration of other systems. In addition, the proposed monitoring approach is built upon an event-based declarative composition design and this results in an integrated approach that allows to reason about the events and does not require to define and extract events from process specification, as the events are first class objects of both design and monitoring frameworks. Properties specification: The proposed approach is highly expressive and allows the specification of monitoring properties that are based on both functional and non-functional (such as temporal, security or their combinations) requirements. These properties are expressed as event-calculus axioms and can be added to the process specification both during process design and during the process execution. Measurement and anomalies detection: The proposed approach both allows for KPI's measurement 1 (that may be needed for process evaluation or result in proactive detection of any violations) and the detection of violations once they happen. Different levels of detection are provided such as detection to the process execution plan, detection to the violations based-on any properties and events added during process execution and others. Violation side-effects: As the proposed approach uses reasoning at the execution-time, it allows for calculating the effects any monitored violation has on the process execution. This also allows to cater for the "ripple effect" any violation has on the process execution, and for proactive detection of any possible violation that is bound to happen later in the process execution, as a result of current detected violation. Forward and backward recovery schemes: Once a violation is detected and a recovery solution (re-planning or alternative path finding) is sought, the proposed approach allows both to find a new solution based on the current process state (thus specifying what steps should be taken now to recover from the violation and hence termed forward recovery) or to backtrack to some previous activity (if possible) and try to find a new from there. Then, any recovery solution takes care of the process specification and the associated QoS properties, when performing recovery. Implementation architecture: The proposed approach uses the DECReasoner as the event-calculus reasoner, however as we discussed in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF], [START_REF]Disc-set: Handling temporal and security aspects in the web services composition[END_REF] the event-calculus to SAT encoding process provided by the reasoner, does not scale well. In this work, we have modified the DECReasoner code to gain substantial performance improvement as evident in performance evaluation results (Section-IX). Further, we have presented a real world crisis management case-study and discussed how a process-based approach can be beneficial.

II. MOTIVATING EXAMPLE

The motivation for our work originates from the need for the process modeling, analysis and monitoring in a crisis situation. A crisis situation is highly dynamic and it demands for a process that is possibly partially defined, is characterized by temporal and security constraints and uncertainty, multiple and possibly changing goals, and thus requires the composition process to be more flexible to adapt to a continuously evolving environment. The crisis scenario brings together two related dimensions of organization and situation measurement. The organization dimension encompasses the design-time composition process modeling while the situation measurement requires the composition process to measure and adapt to continuously changing situation. In our previous work, we have proposed an event-based declarative framework, called DISC, for self-healing Web services composition [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF], and later extended the framework to handle security and temporal requirements in the services composition [START_REF]Disc-set: Handling temporal and security aspects in the web services composition[END_REF]. While we discussed some initial ideas for an event-based monitoring but the focus of our previous work was to justify the usage, expressiveness and benefits of an integrated and declarative approach and in this paper, we propose and discuss the event-based monitoring framework.

For the motivating example, we consider a composition process being setup to semi-automate the recovery plan for the Australian National Herbarium (ANH), Canberra2 . The possible threats to the ANH collection include the bushfire and lighting strikes due to its location at the base of Black Mountain and close proximity to bushland. The ANH recovery plan is in the document form and while we stress the need for a process based approach to the crisis handling, space limitations restrict us to go that far and we will only consider a simple case-study for the recovery of the items for priority salvage and treatment at ANH, after an unfortunate fire accident. These items include the Type specimens and as a result of fire, they may get smoke-damaged and the recovery plan suggest to either freeze or transfer them to some other location.

Once the fire-alarms are activated, the composition process contacts the Web services provided by different services such as fire-brigade, police, ambulance and also invokes a service to call emergency handling staff. Then, once the firebrigade has reached the site and after partial or complete fire containment and given clearance to enter the building, the collection recovery coordinator (CRR), facilities coordinator (FC), Salvage Controller (SC) enter the premises. The role of CRR include the overall management of recovery process while the FC is responsible for ensuring that the recovery teams have proper equipment for the recovery. Then, the SC is responsible for initial cleanup, salvaging, sorting and stabilization of materials by creating recovery teams. The recovery plan suggests the SC can be either Librarian or Collection Manager at ANH. In this work we would not address how such composition can be modeled in a declarative and flexible way [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF], but the focus is to highlight the need of monitoring certain properties during execution as crisis handling process can be highly dynamic. Due to importance and priority of specimens and actively deteriorating situation, we consider the following monitoring constraints to be imposed on the composition process:

• REQ-1: The smoke damaged, wet specimens should be treated as soon as possible and any delay of more than an hour may result in serious damage to the specimens.

• REQ-2: Once the response message (containing updated arrival information) from the fire-brigade and emergency contacts calling services have been received the constraints mentioned above are re-evaluated.

• REQ-3: These constraints must be respected for any recovery solution to cater for monitored violations. For this scenario, these constraints are already known and can be defined at the design-time using a event-based approach [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. However, the successful execution of the process is challenging provided highly dynamic and con-tinuously changing situation. For instance, the time-taken by the fire-brigade and emergency staff to reach the site can be somewhat defined and estimated but the time-taken for the fire-containment process itself is highly relative. Then, it may not be possible to define all the monitoring properties during composition design and even if the designlevel constraints are respected, the occurrence of external events during process execution can have impacts on the process execution. We will use this example as base for describing different aspects of the proposed framework.

III. RELATED WORK

The problem to effectively monitor and recover from the anomalies during process execution is highly active and widely studied research direction and in a broader sense it spans different related domains. Workflow or Process management systems, in general, rely on an exception handling approach to specify exceptions and handles during process design [START_REF] Russell | Workflow exception patterns[END_REF], [START_REF] Weske | Business Process Management: Concepts, Languages, Architectures[END_REF], [START_REF] Vanhatalo | Faster and more focused control-flow analysis for business process models through sese decomposition[END_REF], [START_REF] Vanhatalo | Automatic workflow graph refactoring and completion[END_REF]. Further, for the self-healing systems a number of approaches have been proposed for monitoring, diagnosis and recovery from errors during execution [START_REF] Ghosh | Self-healing systems -survey and synthesis[END_REF], [START_REF] Griffith | Multi-perspective evaluation of self-healing systems using simple probabilistic models[END_REF]. A detailed discussion about monitoring and recovery in different systems can be found in [START_REF] Friedrich | Exception handling for repair in service-based processes[END_REF] and space limitations restrict us to the discussion of monitoring and recovery mechanisms for only services based processes, where different services are composed using the approaches such as BPEL. Traditional services composition approaches, such as BPEL, build upon the exception handling approach for errors handling and allow to define different type of exception handlers and corresponding actions based on process state. However, it may not be always possible to foresee errors and specify the exceptions at the design-time. In the literature, a number of composition process monitoring approaches have been proposed, but in general, they are proposed as an extension to some particular run-time and are tightly coupled and limited to it [START_REF] Beeri | Bp-mon: querybased monitoring of bpel business processes[END_REF], [START_REF] Baresi | Comprehensive monitoring of bpel processes[END_REF], [START_REF] Sun | Monitoring bpel-based web service composition using aop[END_REF], [START_REF] Wu | Flexible pattern monitoring for ws-bpel through stateful aspect extension[END_REF]. As a result and they do not consider other sub-systems and or processes that can be used for monitoring [START_REF] Moser | Event driven monitoring for service composition infrastructures[END_REF].

Then, the traditional monitoring approaches [START_REF] Barbon | Runtime monitoring of instances and classes of web service compositions[END_REF], [START_REF] Baresi | Dynamo + astro: An integrated approach for bpel monitoring[END_REF], [START_REF] Mahbub | A framework for requirents monitoring of service based systems[END_REF] build upon composition frameworks that are highly procedural, such as BPEL, an this in-turn poses two major limitations. First, they limit the benefits of any event-based monitoring approach as the events are not part of the composition framework and functional and non-functional properties are not expressed in terms of events and their effects. Secondly the use of procedural approach for process specification does not bridge the gap between organization and situation in a way that it is very difficult to learn from run-time violations and to change the process instance (or more importantly process model) at execution time, and it does not allow for a reasoning approach allowing for effects calculation and recovery actions such as re-planning or alternate path finding as we discussed in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. In [START_REF] Moser | Event driven monitoring for service composition infrastructures[END_REF] authors proposed an event based monitoring approach that works on the message-level and thus is unobtrusive, independent of run-time and that highlights the need and motivation for using an event-based monitoring framework. However the approach aims to extract and define events from procedural process specification, while our approach builds on an eventbased framework and events are first class objects in both composition design and monitoring framework. This allows to reason about events during execution and allows for effects calculation and different types of recovery actions. In [START_REF] Kowalski | A logic-based calculus of events[END_REF] authors attempt to add monitoring directives to a declarative approach but still the approach lacks expressiveness and does not allow for recovery actions. Our work can be compared to PAWS framework [START_REF] Ardagna | Paws: A framework for executing adaptive web-service processes[END_REF], in which authors propose to add annotations to the BPEL process to handle services replacement in case of run-time failure. However, as the approach is based on BPEL and is procedural, it allows for limited recovery options (such as service replacement and not re-planning or alternative path finding) and effects calculation once a violation is detected. In [START_REF] Friedrich | Exception handling for repair in service-based processes[END_REF] authors proposed a model based approach for repair by exploiting information about the causes of process and deriving repair strategies based on process structure, however the approach builds upon BPEL and PAWS and thus does not allow to reason about monitoring properties and allowing for effects calculation and different recovery schemes.

IV. BACKGROUND

A. The DISC and DISC-SeT frameworks

We have proposed a declarative event-oriented framework, called DISC (Declarative Integrated Self-healing web services Composition) [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF], that serves as a unified framework to bridge the gap between the process design, verification and monitoring and thus allowing for self-healing Web services composition. The proposed DISC framework has four main stages, Composition design, Instantiation and Verification, Execution and Composition monitoring (see Figure -1). The composition process starts when the user provides the composition design, which allows to accommodate various aspects such as partial or complete process choreography and exceptions, data relationships and constraints, Web services dynamic binding, compliance regulations or other non-functional aspects (see Figure 1-1). The process design (and so as other process life-cycle stages) is based on event calculus and a detailed discussion about the motivation for the usage of event-calculus and models for different aspects can be found in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. The event-calculus model for the composition design is then used to instantiate, verify and execute the composition process (see Figure 12). The instantiation phase involves finding a solution to the composition process using the event calculus reasoner. As our proposal allows for specifying only the boundaries to the composition process and, the instantiation may result in a number of solutions and the user can be given option to choose one solution, this choice can also be based on some other criteria such as overall cost, minimal time and others. The chosen plan is then executed and the plan generated by the reasoner serves as a script for the execution of the process (see Figure 123). However, If there are some conflicts in the composition design and/or the specified constraints are too strict, this leads to empty solution set and the the reasoner can return near-miss models and/or conflicting clauses highlighting the strict constraints or the conflicts. The process is then monitored during execution using an event-based monitoring approach, that is the focus of this paper (see Figure 1234) and in case of any violation, process specification can be updated and re-instantiated to find an updated solution. We have also extended the DISC framework to propose the DISC-SET framework [START_REF]Disc-set: Handling temporal and security aspects in the web services composition[END_REF] to add the security and temporal properties representation, computation and verification.

B. Event-calculus

The DISC framework is based on event-calculus (EC) which is a logic programming formalism for representing events and their side-effects. It comprises the following elements: A is the set of events (or actions), F is the set of fluents, T is the set of time points, and X is a set of objects related to the particular context. In EC, events are the core concept that triggers changes to the world. A fluent is anything whose value is subject to change over time. EC uses predicates to specify actions and their effects. A detailed discussion about event-calculus can be found in [START_REF] Kowalski | A logic-based calculus of events[END_REF] and we discussed the motivation for usage of event-calculus in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. Some basic event calculus predicates used for modeling the proposed framework are:

• Initiates(e, f, t) -fluent f holds after time point t if event e happens at t.

• Happens(e, t) specifies that event e happens at time point t.

• HoldsAt(f, t) is true iff fluent f holds at time point t.

Given an event-calculus based specification, different reasoning modes can be used and Figure-2 summarizes different reasoning modes used during different process stages.

C. Example

Using the DISC framework for the process specification we can model the composition process for the motivating example in a declarative and flexible way [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. We can define events/fluents for services invocation, for activities representation and domain specific events such as modeling the arrival of support staff. For simplicity, we will abstract different processes such as fire-containment, recovery and the responsibilities of the collections coordinator and other users as activities however they can be service based sub-processes. We consider the following design-level constraints; the firefighters arrive within 15 minutes after the service invocation, the support staff arrival varies and may take 25 minutes for their arrival. Then, the time taken for the fire-containment process is highly relative and provided the central location of priority salvage items, it may be possible to contain the fire within 20 minutes. Finally, the recovery process may take 10 minutes once fire is (possibly partially) contained. Space limitations restrict us to discuss the design model in detail and we here present the instantiated solution returned by the reasoner, the serves as a plan for process execution and we will use it as a base for monitoring violations detection. The instantiated model is shown below: The instantiated model shows that there exists a solution based on design level contracts,the left column shows the time points while the right column shows the event or process state (+ sign shows that a particular fluent holds at that time point). We will use this instantiated model as base for describing different aspects of the proposed monitoring framework.

V. PROPOSED MONITORING FRAMEWORK

The proposed event-based monitoring framework allows to specify and reason about the monitoring properties during composition process execution. The composition process is specified using the event-calculus and is then used to instantiate, verify and execute the composition process (see Figure 3-➀). The instantiation phase involves finding a solution to the composition process using the event calculus reasoner and the instantiated plan is then executed using the execution engine (see Figure 3-➁). The proposed monitoring framework (see Figure 3-➂) works during the composition process execution and is divided into three phases. The specification phase requires the user to specify the functional and non-functional properties that needs to be monitored to identify anomalies or needed for KPI's measurement. Then, the detection and effects calculation phase is both responsible for detecting any violations based on the specified properties and to calculate the side-effects the detected violation has on the overall process. Then, the response phase uses the userspecified actions to respond to the monitored property. In the sections to follow, we will first discuss the monitoring properties specification in Section-VI and then will discuss how the detection and effects calculation works once a violation is detected, in Section-VII. Then, we will discuss the possible response actions to cater for the monitoring properties, in Section-VIII.

VI. PROPERTIES SPECIFICATION

The specification phase requires the user to specify the functional and non-functional properties that needs to be monitored to identify anomalies or needs for KPI's measurement. The properties that need to be monitored are added to process description either at the process design (if they are already known -figure 3-➀) or they can be added to the process specification at the execution time. In the later case the process specification is updated and an updated instantiated solution is sought, in order to verify any conflicts and to get an updated execution plan as a result of process change during execution (see Figure 3-3➝1).

Properties that can be monitored include the functional aspects such as monitoring the invocation and execution order or they can be based on non functional aspects such as temporal aspects requiring to monitor the response time for a service, delay between successive invocations of the service or monitoring invocation time-frame for a service. Further, the properties can also be based on data such as monitoring the data availability, validity and expiry or based on the security properties such as monitoring the data integrity, confidentiality, access-control. The choice of highly-expressive event-calculus formalism even allows to combine the properties related to temporal, security and other aspects such as monitoring the data validity and access control within specific time frame which may be needed for instance, during dynamic task delegation (see [START_REF] Gaaloul | Dynamic authorisation policies for event-based task delegation[END_REF] for details). Below we discuss event-calculus models for some of these properties:

Happens(StartInvoke(S1), time1) & Happens(EndInvoke(S1), time2) & time2 -time1 = SomeTimeValue → Happens(Terminateprocess(), time2). Happens(InvalidateResponse(service), time) → Happens (SendAlertNotification(), time).

The first axiom in the model above specifies a monitoring property for monitoring the response time for a service. If the difference in the occurrence of the Start and End event is greater than SomeTimeValue, the process is terminated. The monitoring properties have the general form P roperty → Response and we will discuss different response actions later in Section-VIII. The second axiom above specifies to send Alert notification once the response message from any service does not remain valid. Space limitations restrict us to discuss event-calculus models for other aspects, a detailed discussion about how different security and temporal aspects can be modeled using event-calculus can be found in [START_REF]Disc-set: Handling temporal and security aspects in the web services composition[END_REF].

Regarding the motivating example, we first consider different monitoring properties already known at the composition design stage as identified in the motivating example. The event-calculus axioms for these properties have been added to the composition design, and thus the solution returned by the reasoner caters for these properties (see Figure 3-➀). Then, as the proposed approach also allows to specify the monitoring properties during process execution, we consider the following properties added to the process specification once the response message from the fire-brigade and emergency staff calling services have been received.

• REQ-4: Arrival time of staff members (and completion of activities) should be logged.

• REQ-5: Salvage process should only be handled by Collection manager as the Librarian does not possess the expertise to handle the degraded specimens. However in the presence and help from the conservator, he can handle the salvage process. Adding the monitoring properties may require updating the process specification (see Figure 3-3➝1), such as new axioms/event for logging should be added. The last axiom in the event-calculus model below handles the REQ-5 while other axioms handle REQ-4:

Activity LogArrival Happens(Arrives(user), time) → Happens(Start(LogArrival), time). Happens(Start(SalvageControllerProcess), time) → HoldsAt(HasArrived (Col-lectionManager),time).

VII. DETECTION AND EFFECTS CALCULATION A. Detection

The detection of the violations can be handled at different levels using the proposed framework. At a basic level we first consider the violations to the execution plan, which is handled by maintaining an event repository which keeps track of all the messages exchanged between the composition process and the participating services during process execution. This repository is then used to find any mismatch between the temporal ordering of actual events and the ones mentioned in the initial instantiated plan. Using the basic detection technique, it is possible to find violations to the execution plan or the invocation and execution order of the services. However such a detection may not be useful in detecting data values based or other low-level violations, as using the event-calculus, the process is modeled at an abstract level. This can be handled by also abstracting the processing of verifying the data values and other low level service details by using event-calculus fluents. For instance, we can have a fluent ResponseValid(SomeService) and an event called ValidateResponse(SomeService), and whenever data is received from a service we check for its validity. Then, if the data is not considered valid, based on application level checks on data, the fluent ResponseValid(SomeService) does not hold and in-turn results in a mismatch between the initial instantiated plan and actual service execution. The detection phase may thus require the execution engine support (for instance checking data validity, see Figure 3-➁).

Then, in order to detect the monitoring properties added at the execution time (e.g. based on external events not there in the initial instantiated plan), the "abduction reasoning" mode can be used by adding the newly added events and monitoring properties to the process model and re-invoking the reasoner. In case of no conflict and violation, the reasoner returns an updated plan based on the added events and monitoring axioms. However, if there is some conflict based on addition of new events or if the newly added monitoring property is not satisfied, the reasoner returns a set of unsatisfied clauses highlighting the error. The detection phase may thus also require the reasoner support (see Figure 3-3➝1).

B. Effects calculation

Once a violation to some monitoring property is detected, the effects calculation phase is responsible for calculating the side-effects this violation has on the overall process flow. This allows to prioritize the violations based on their impact and it may be possible to ignore some violations, for instance if the response time delay for a service has no effect on the overall process goal and other functional and non-functional properties associated with the composition process. As the proposed approach allows to reason about the composition process and as the approach is based on event-calculus with different reasoning modes, the effects calculation is achieved by adding the partial plan with the violation to the initial plan and re-invoking the reasoner. Although the process may seem similar to the detection of monitoring properties added at the execution-time, there is one major difference; instead of using the "abduction reasoning" we use "deduction reasoning" in the effects calculation phase. This may further allow to foresee any anomalies which may not be evident now but may happen later in the process execution. The effects calculation phase thus requires the support from the event-calculus reasoner to perform deductive reasoning (see Figure 3-3➝1).

C. Example

Let us now review the monitoring properties identified earlier for the motivating example and discuss how any violation to these properties can be detected. The properties REQ-1 and REQ-3 are implicit and these properties are evaluated whenever the reasoner is reinvoked. For instance, the property REQ-1 specifies the composition goal and is evaluated every time the abductive reasoning is sought. Then, the property REQ-2 relies on application level data validity checks and requires to update the process specification based on data received from the participating Web services. The event added at the design-time, ValidateAndUp-datePlan(service), models this behavior. Then, updating the process specification during execution may result in conflicts and inconsistencies, such as the axiom added for REQ-5 may contradict with the one already there in the process description. However, the proposed framework allows to identify and resolve these conflicts as adding these axioms and re-invoking the reasoner will either provide an updated solution (as for REQ-4) or will return the conflicting clauses. Adding property REQ-4 to the specification and invoke reasoner for "abductive reasoning" returns the following updated model: The model above shows that adding the execution-time properties can result in a conflict, as at the design time it was specified that either the Librarian or Collection Manager can perform the role of SC and a solution exists at design time (showing Librarian can be there early and do the job). However, at execution time, the constraint has been modified to only allow Collection Manager to act as a SC and as he is not there, the process shows there is a conflict. However, the property REQ-

VIII. RESPONSE

The response for the monitoring properties may involve some domain specific actions to cater for or measure the KPI's and other parameters (such as logging, performance evaluation) needed for the successful process execution. Then, in order to cater for the monitoring violations detected at the execution time, different recovery actions can be used in-order to recover from the violation. These actions may include to ignore the violation, terminate the process, reinvoke or substitute the service, find an alternative solution based on current process state or backtrack to some previous state and then seek an alternative solution and others. Below we briefly discuss the alternative-path as a recovery action as it highlights the need for a reasoning-based approach.

The recovery process is handled by adding the current process state (with the violation) and re-invoking the reasoner to perform abductive reasoning for the goal. However, it is not always possible to recover from a violation AND respecting the associated constraints and composition goal. As a result, some constraints may require to be relaxed and the proposed approach allows to identify the conflicting clauses and hard-constraint if a recovery solution is not possible. The proposed approach thus preserves all the functional and non-functional constraints associated with the composition process (unless needed to be relaxed) while performing recovery. Further, the proposed approach allows both to find a new solution based on the current process state (thus specifying what steps should be taken now to recover from the violation and hence termed forward recovery) or to backtrack to some previous activity (if possible) and try to find a new from there. The response phase may require the execution run-time support (for instance actions such as logging, KPI's measurement, see Figure 3-3➝2) and may also require the support from the DECReasoner in order to do abductive reasoning for actions such as finding alternatives (see Figure 3-3➝1).

In relation to the motivating example, we will consider the case when the fire-containment process is taking more time than initially estimated. As a result, a violation is detected at time point and a recovery solution is sought requiring to find alternative path for successful process execution. As a result, the reasoner is re-invoked with the updated process state (with the violation and new estimate for the fire containment, it would probably take 30 minutes instead of 20 minutes, as planned) and we get the updated model as below: The updated model shows that even with the violation, the goal is still achievable satisfying all the associated constraints. However, had it not been the case, some constraints may need to be relaxed (if possible) to achieve the goal.

IX. PERFORMANCE EVALUATION

In order to test our proposal, we have implemented the proposed model using the discrete event calculus language [START_REF] Mueller | Commonsense Reasoning[END_REF] and discussion about the implementation architecture for the DISC framework can be found in [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF]. The proposed monitoring approach requires to reason about the composition process at various stages of the framework. In our previous work [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF], [START_REF]Disc-set: Handling temporal and security aspects in the web services composition[END_REF] we concluded that although the solution finding by SAT solver is highly efficient, the event-calculusto-SAT encoding process does not scale well with the increase in time points and complexity of the composition process. In this work, we have thus modified the encoding process by two approaches. First, the process encoding is done only once during the instantiation phase of the DISC framework and encoding for any subsequent changes to the process description, such as during process execution or during effects calculation phase of the proposed monitoring framework, is added to the initial process encoding. Then, we have modified the c language code for the encoding process (changes include modifying the hash function to have less collisions) and the results show a substantial gain in performance. The performance evaluation tests for the motivating example were conducted on a MacBook Pro Core 2 Duo 2.53 Ghz and 4GB RAM running Mac OS-X 10.6. The DECReasoner version 1.0 and the SAT reasoner, relsat-2.0 were used for reasoning. The performance evaluation results are shown in Figure -4, with Y-axis showing the timetaken in seconds while the X-axis showing the problem size, which is obtained by multiplying the composition problem (with same dependencies) and increasing the time points. This results in a highly complex process needed to test the original and modified encoding process. The performance evaluation results show substantial gain in event-calculus to SAT encoding process. The solution computation by relsat solver is highly efficient and the recovery process always takes less (or same) time than the initial solution as we have a partial plan and that reduces the problem size.

X. CONCLUSION

In this paper, we have presented an integrated eventbased framework that allows to specify and reason about the monitoring properties during process execution. The proposed approach builds upon an event-based declarative composition design [START_REF] Zahoor | Disc: A declarative framework for self-healing web services composition[END_REF] and does not require to define events as an extension to the composition design as the events are first class objects of both composition design and monitoring framework. The proposed approach is highly expressive and allows the specification of monitoring properties that are based on both functional and non-functional (such as temporal and security) requirements, that can be added to the process specification during design or process execution. Further, it allows for identifying any violations based on the specified properties and for calculating the effects any monitored violation has on the overall process execution. Then, any recovery solution takes care of the process specification and the associated QoS properties associated with the process. We have presented a real world crisis management case-study that highlights the proposed framework. Further, we have modified the encoding process for DECReasoner tool, as it does not scale well, and it results in substantial performance improvement.

Figure 1 .

 1 Figure 1. The DISC Framework

Figure 2 .

 2 Figure 2. EC Reasoning modes for the DISC framework

Figure 3 .

 3 Figure 3. Proposed monitoring framework

  (CollectionCoordinator), 25). Happens(Arrives(CollectionManager), 25). Happens(Arrives(Librarian), 25). Happens(Start(LogArrival), 25)... The model above now contains the events added for logging and instructs the execution engine to log the arrivals of support staff. Further, adding the monitoring property, REQ-5 and re-invoking the reasoner, returns the a set of conflicting clauses including the following: 2708 -550 0: (HoldsAt(HasArrived(CollectionManager), 36) -!Happens(Start(SalvageControllerProcess), 36)).

Figure 4 .

 4 Figure 4. Performance evaluation results

  5 allowed Librarian to do the task if Conservator is there. Let us consider that the Conservator does arrive in time, and re-invoking the reasoner gives following updated model:

		...
	35	Happens(Arrives(Conservator), 35).
		Happens(End(FireContainement), 35)
	36	+Finished(FireContainement). +HasArrived(Conservator).
		Happens(Start(CollectionsCoordProcess), 36). Happens(Start
		(FacilitiesCoordProcess), 36). Happens(Start(SalvageControllerProcess), 36).

We will collectively use the term KPI's measurement in the paper, however it can signify monitoring the resource utilization, SLA's fulfillment, or some domain specific KPIs that may be required to measure the performance or to fulfill some domain specific monitoring requirements.

http://www.anbg.gov.au/cpbr/disaster-plan/


Marc Demeuse
email: marc.demeuse@ulg.ac.be

Ariane Baye

Marie-Hélène Straeten

Julien Nicaise

Denis Meuret

Sophie Morlaix

Denis Maguain

Luciano Benadusi

Giuseppe Ricotta

Orazio Giancola

Stephen Gorard

Emma Smith

Alejandro Tiana-Ferrer

Noelia Alvarez

Marisa García De Cortázar

Set of Indicators (European Group of Research on Equity of the Educational Systems)

The paper is not the result of an individual work but the fruit of an international and pluridisciplinary two years research partially funded by the

 October 9-11, 2003Equity of the European Educational Systems. A Set of Indicators (European Group of Research on Equity of the Educational Systems) 2 A good overview of the initial framework is the collective book from Hutmacher, Cochrane and Bottani (Eds) (2001), especially the Meuret's chapter entitled "A System of Equity Indicators for Educational Systems".

The purpose of the present paper is first of all to introduce the final framework and to give an overview of the coherent system of indicators included in it. Based on this initial framework, the European team also offers a coherent point of view in order to link the available data but the open structure of indicators could offer other readings and open a large discussion on equity in education in Europe.

Résumé

Ce texte n'est pas le résultat d'un travail individuel, mais le fruit du travail, durant deux ans, d'une équipe internationale et pluridisciplinaire, financée partiellement par la Direction générale de l'Education et de la Culture de la Commission européenne dans le cadre du programme Socrates (SO2-61OBGE). Six équipes [Universités de Liège et de Louvain-la-Neuve (Belgique), de Bourgogne (France), de Rome (Italie), de Cardiff (Royaume uni) et de Madrid (Espagne)] ont ainsi été impliquées dans ce projet. Le texte que nous présentons ici tente de fournir un aperçu d'un rapport de 200 pages (L'équité des systèmes éducatifs européens. Un ensemble d'indicateurs) publié en français et en anglais, et disponible sur le site Europa de la Commission européenne5 . L'objectif général du projet est d'offrir un cadre conceptuel et un ensemble d'indicateurs d'équité en matière d'éducation. Le rapport a été publié en juillet 2003. De nombreuses sources sont utilisées (principalement les résultats d'enquêtes internationales), y compris une enquête réalisée auprès d'élèves de 14 ans à propos de leur perception de la justice dans cinq régions d'Europe (en Communauté française de Belgique, à Paris, à Cardiff et sa région, à Rome et à Madrid). Cette enquête, baptisée « étude pilote sur le sentiment de justice à l'école », a été construite en fonction des objectifs du projet et de son cadre conceptuel.

Un aperçu du cadre conceptuel de départ peut notamment être trouvé dans l'ouvrage collectif édité par Hutmacher, Cochrane et Bottani, en 2001, plus particulièrement dans le chapitre rédigé par Meuret sous le titre « A System of Equity Indicators for Educational Systems ».

L'objectif de notre texte est avant tout de présenter le cadre conceptuel qui a été finalement adopté par l'équipe de recherche et de donner un aperçu de l'architecture du système d'indicateurs. Au départ de ce système d'indicateurs, l'équipe de recherche européenne propose également une lecture cohérente de manière à lier les différentes informations collectées, même si la structure adoptée est relativement ouverte et permet d'autres lectures, ouvrant ainsi la possibilité d'une large discussion autour du problème de l'équité éducative en Europe.

Aims of the project

The project is intended to help to measure and compare the equity of the various education systems in the European Union Member States. Thanks to it, decision-makers and users will be informed of the equity of the existing systems. This informative tool may help decisionmakers to (re)define the educational politics.

Structure of the report

The report is structured into three parts. A first part, entitled "Devising indicators of equity of educational systems: why and how ?", defines the concepts of equality and equity, and presents the framework of indicators and its guiding principles. The second part, "A set of indicators on the equity of the educational system", presents the twenty-nine indicators built in the context of this project, and organized according to the framework. The third part, "The equity of European educational systems. An interpretation of the 29 indicators", presents an analytical interpretation of the equity indicators.

Why speak about equity ?

The first decision of our international team was to move from equality to equity. Nevertheless, anyone who talks about equity rather than equality is generally suspected of having abandoned safe territory and a clear concept for a minefield and a fuzzy concept. For many of the supporters of egalitarian views, the main appeal of this new positioning would be to justify unjustifiable inequalities for the benefit of the dominant class. Therefore, some explanation is required on this point. It is true that equity is a more difficult concept than equality, and that it allows, in its principle, inequalities; nevertheless, it is a concept that allows to go beyond a purely formal examination to perform a multidimensional analysis. In fact, the strictly egalitarian vision, which aims to give everyone the same treatment, while ignoring the characteristics of each individual at the outset, or even, the results in terms of reproduction of the initial inequalities, forces us to question its very foundations, precisely for reasons of equality. The central question, as stressed by [START_REF] Sen | Inequality re-examined[END_REF], is not equality or inequality but "Equality of what ?". By the way, we move from a supposed very simple question to a more complex one and from a world of certainty to a quite complex situation where differences could be legitimate and equalities could be perceived as unfair.

Keys to open minds and discussions

Adapted from [START_REF] Grisay | Les mirages de l'évaluation scolaire[END_REF], the following table gives an overall vision of the five major principles of equality in terms of education, and presents the postulates and the consequences of these various principles of justice.

The first concept, not specified by Grisay, and marked "A" refers to a "natural", or Libertarian concept. Only concepts B to E really draw on the principles of equality (see also [START_REF] Demeuse | Efficiency and Equity[END_REF].

Whether we talk about equal opportunities (B), equal treatment (C), equal achievement (D) or equal results, we stumble over the practical or theoretical limitations connected with the adoption of a particular theory.

So, in the first case (B), the wish is that the social background does not influence success at school, but this is subject to criticism by those who claim that this leaves the possibility open to give better educational conditions to those with greater ability, which is traditionally known as the "Matthew effect"6 .

In the second case (C), the same educational conditions are given to all, but this is open to criticism from those who think that some people, because they suffer from a handicap of one kind or another, need better educational conditions.

In the third case (D), equality of results is desired, at least for a certain level of knowledge, but this comes up against those who claim that by pursuing this objective, the best pupils are deprived of the possibility of progressing as far as possible, which is referred to as the "Robin Hood effect".

Table 1. Five principles of equality in education (adapted from Grisay, 1984, p. 7).

Assumed

Admitted Criticized Recommended A -No interest in equity: "natural" and "libertarian" positions Birth, strength or belonging to a particular group determine rights. Liberty can only suffer from forced redistribution.

Reproduction and maintenance of the "natural" order and differences based on fair acquisition.

Possibly, inequalities in groups of peers. Interventions contrary to liberty.

A stable order, a sharing of functions (society of castes, orders, etc.) or a system based on liberty of the actors.

B -Equality of access or opportunities

The existence of talents, of potential or natural aptitudes. These define the level or threshold that the individual may hope to achieve.

Unequal results, provided that they are proportional to aptitudes at the start. Existence of courses of study of unequal value. Inequality of treatment.

The fact that merit is not the only criterion for access to the most highly-regarded courses. Socio-cultural bias affecting guidance tests. Imperfections in the evaluations responsible for the fact that, despite equal competence, one pupil succeeds and another fails.

Objective and scientific detection of talents, and scientific methods of orientation. Equality of access to long courses of study, for children of equal aptitude from advantaged and disadvantaged backgrounds.

A school made to measure, i.e. a varied system of options and courses of education adapted to the ability of students. Aid to gifted pupils from disadvantaged backgrounds (scholarships, etc.).

C -Equality of treatment

The capacity of all to undertake basic learning, and therefore benefit from basic education.

The existence of natural talents, potential or aptitudes. Unequal results, on the condition that pupils were able to benefit from learning conditions of equivalent quality.

Unequal quality of teaching, responsible for unequal achievement. Elite schools, ghetto schools, streamed classes, explicit and implicit courses of study that engender unequal quality of education.

The Single-level or Comprehensive school, and particularly, the common core for lower secondary education.

D -Equality of achievement or academic success

Potential for extended learning. Individual characteristics (cognitive or affective) can be modified. Differences in learning styles.

Differences in results beyond the essential skills.

The ideology of talents. Negative discrimination (including streamed classes, courses, elite schools and ghetto schools), i.e. all the situations where unequal quality of teaching amplifies the inequalities at the outset.

Equality of achievement for the essential skills. Positive discrimination, mastery learning, formative assessment, as well as all the support mechanisms aimed at reducing the initial inequalities.

E -Equality of actualisation (social output)

Different individual, motivational and cultural characteristics, but without any hierarchy existing between them.

Differences in profile of the results.

The existence of a single standard for excellence. An "elite" culture and a "subculture".

Individualized instruction.

While each principle of educational justice has its own limits, the adoption of one principle or another poses an even more fundamental problem: this is that it places educational fairness in the sphere of "local" justice. Education is considered as an "asset" in itself, whether it is situated in relation to other more basic assets and in relation to more general principles, that is why the last level (E), proposed by Grisay, broadens the perspective by putting school back into its societal context. Nevertheless, beyond this refocused perspective, to borrow Rawls' term, educational fairness is often considered in the context of "intuitionist" theories. According to Rawls, these theories have two types of drawback: they rely on several principles that could prove to be incompatible, and they offer no priority rules that would enable these priorities to be ordered by priority [START_REF] Rawls | A theory of justice[END_REF]. Therefore, one could conclude that it is not worth measuring inequalities because the relevance of any indicator could be challenged by the supporters of another principle of justice. October 9-11, 2003 Equity of the European Educational Systems. A Set of Indicators (European Group of Research on Equity of the Educational Systems) 6 Since the publication of A Theory of Justice by Rawls in 1971, a debate has been ongoing within political philosophy, from which several general theories have been developed, in which it is possible to imagine justice in education while avoiding "local" and "intuitionist" approaches. However, these fascinating debates do not provide a universally-acknowledged theory of justice that would enable us to devise an unchallenged measurement of educational equity, but do enable a discussion to be held on education in the context of a general debate about justice. In other the existence of several principles does not lead them to invalidate each other, but to consider the issue of justice within the framework of the discussion they provoke. There are many principles of justice that can be invoked to justify actions, practices, or situations, and the theories help us to find our bearings among them.

Once there is a discussion between the concepts of justice, rather than the juxtaposition of contradictory principles, as can be seen from the table above, a system of indicators is useful, because it provides input from reasoned comparisons and probative facts. The indicators presented here are intended to provide input to the debate on justice in education, by offering some elements of responses to the following questions proposed by Meuret during our works:

To what extent do individual educational inequalities have major social consequences for the individuals ? What is the importance of those inequalities ? Are they due mainly to the context, or rather to the process of the educational system ? Are they used to help the disadvantaged ?

What is the importance of educational inequalities between girls and boys or between groups of different social, economic or national origins ? To what extent are they due to the societal context or rather due to the process of the educational system ? To what extent are they aggravated by the society or the labour market ?

To what extent does being below a minimum skills threshold have important consequences for the individuals in and outside the school context ? What is the proportion of individuals who find themselves below that threshold ? What proportion of each group is beneath that threshold ? Is the fact of being below the threshold due mainly to the socio-economic context or rather to the educational system itself ?

A coherent set of indicators

Why a set of indicators of equity ?

Indicators measuring inequalities have been appearing for a long time in international publications dealing with education, particularly in the OECD Education at a Glance, and in Key data on education in Europe, the regular publication of the European Commission prepared by Eurydice. The various reports produced as a result of international evaluations of students achievement (for instance, OECD, 2001;Beaton et al., 1996a and b) also contain indicators on inequalities. In addition, several international education research programmes have proposed comparisons (Shavit and Blossfeld, 1993;Müller and Karle, 1993) in important fields like social inequalities in school careers. Other international surveys (European Households Panel, European Value Survey, Luxembourg Income Study, etc.) also provide interesting information, as do certain national surveys. However, the latter do pose sizeable compatibility issues. [START_REF] Meuret | A system of equity indicators for educational systems[END_REF] on which basis the current project took shape. The new feature of this work is its systematic -we tried to determine the principles to give us some points of reference in a vast and relatively new field -and comparative approach of the equity of European educational systems.

We need now to have indications about efficiency and equity, since we can no longer settle for indicators about the former (Education at a Glance, for example) and pious wishes about the second. It is for this reason that it is essential to publish indicators about the equity of educational systems with the intention of providing useful information to the citizens as well as those responsible for the educational system. These indicators are intended to provide a needed supplement to the information already available about costs and results.

How to read our set of indicators ?

Our set of indicators is structured according to two dimensions or axes (see table 2). The first dimension is related to the nature of the observed differences or relative positions: (1) differences between individuals, (2) differences between groups and (3) threshold beneath which fairness dictates that nobody should be situated. We have privileged, in our analyses, the "natural groups", i.e. those to which the individual belongs whether he/she wants to or does not want to : gender, nationality and social origin. The second dimension takes of course into account inequalities in the education processes (B) and inequalities of education as the internal results of schooling (e.g., diplomas) (C), but also the context of inequalities in education (A) and social and political effects of inequalities in education (D) as external results of schooling.

Taking into account the available data, we operationalised the theoretical framework for devising equity indicators into twenty-nine indicators. Their chronological organization follows the vertical axis of our framework (context, process, internal results, external results), while the horizontal axis can be felt in the comments and the graphs presented (inequalities between individuals, between categories and thresholds of equity). In order to facilitate the reading of our indicators we have adopted an identical way to report each of them (see Figure 1). Each indicator is then presented on double sheets: the graphics and tables are found on the right-hand page, while the comments and technical notes are opposite, on the left page. At the bottom of the left hand page, the coloured boxes indicate the EU States Members for which indicators have been built7 . In the upper right-hand corner, a letter and two numbers identify the indicators. According to Table 2, the letter refers to one of the four main domains (see our second dimension of the framework) while the two numbers refers to subcategories (for example, A. context of inequalities in education > 1. individual consequences of education > 1. Disparities in income and access to employment). The indicators drawn from the European pilot survey on feelings of justice at school are distinguished from the other indicators by a coloured page background, due to their experimental nature.

Table 2. The theoretical framework of indicators on the equity of educational systems

A system of indicators on the equity of educational system (1) Inequalities between individuals (2) Inequalities between groups (3) Individuals below the threshold A. Context of inequalities in education

Data sources

We had to find some data sources which would enable to cross each field (second dimension) with different situations of inequality (first dimension). The goal of the authors was to identify international data in which at least three countries of the European Union are represented ; this explains why some surveys conducted at a national level have not been taken into account. The authors also wanted to diversify the information sources, meanwhile these had to be valid and well-documented. These sources are mentioned in the Table 3.

Finally, in the case of some of the retained fields, the authors could only notice the lack of information at the international level. They thus organized a pilot survey in the five partner countries in order to supply indicators (with exploratory purposes) about feelings of justice at school9 .

Therefore, one must consider these deficiencies not as a lack of interest by the authors, but as evidence of a genuine lack of available or useable data. The most critically lacking data, in our opinion, could be obtained from the following information systems: -a poll on judgements and criteria of fairness with regard to education on the scale of the European Union taken among citizens; -a test which would enable to check whether, when young Europeans leave initial education, they possess the minimum skills to live an independent and responsible life; -a system allowing to measure and compare, on the same scale, the skills of students who leave the education system earliest and latest; -a test that would enable to measure the basic skills of adults who have left the education system, in relation to their personal characteristics, including fields not yet investigated.

-data on the inequalities of economic, physical and social insecurity, to the extent that in certain countries, gains in security of the working classes encouraged the reduction of social inequalities in education (Shavit and Blossfeld, 1993); -data on certain social benefits of education, such as effects on health; -data on inequalities in expectations of parents or teachers, to the extent that these are powerful predictors of the effectiveness of teaching;

The data collected through the different mentioned sources have been statistically processed in order to support the way on which we had decided to develop the indicators. The definition of categories and thresholds can have suffered some differences because of the distinct available information sources. For instance, all the studies do not enable to compare the pupils according to their social origin. In the same way, it is sometimes possible to determine some qualitative thresholds (for instance, a level of competence), whereas it may be better to use a quantitative threshold (for instance, the 10% of the lowest pupils).

Finally, it seemed essential to propose to the possible readers an analysis of the assessed data. That analysis is presented as a synthetic comment which helps the citizen who wants to grasp the information, to understand better the presented diagrams and tables. Our definition of what an indicator is can be resumed as follows: a piece of statistical information, reliable and readable, which supplies a clear indication to the policy makers and actors of the education systems. Comments, tables and diagrams have been designed to answer that demand. When needed, the information has been completed in a technical and more accurate appendix, which supplies data about the methods of assessment which have been used.

In conclusion, three key words have been guiding our methodological approach : quality of the collected data, relevance of the selected information in relationship with the framework, and readability of the presented data, for the citizens as well as for the persons who wish more technical information. 12 IEA, national organizations, research teams, etc. ) were invaluable, but we have to admit they are not yet sufficient to exhaust the theme of educational equity.

As an example, the authors could not investigate enough the particular structures of the European school systems (level of autonomy of the schools, level of freedom in the choice of the school for the parents of pupils, diversity of the school training tracks, frequency of the grade retention, position of the private schools in relationship with the public schools, etc.) nor the particular means implemented to compensate for the various types of identified inequalities (system of positive discriminations, financial supporting grants for the pupils and their parents, etc.). At the European Union level, those topics are over all in the domain of the units of Eurydice but, in the future, it will not be superfluous to take into account more systematically those subjects from the specific angle of educational equity and of school justice as a whole. Furthermore, far from pretending to self-sufficiency, even if the 29 indicators propose an original and completely new reflection and work foundation, they also widen significantly the perspective by supplying a relatively easy anchoring for the processing of future new data.

In prospective terms, it seems useful to ensure the reproduction and the continuity of such a work, because the complex issue of equity of educational and training systems in Europe is only beginning to emerge for their managers and their users. Indeed, whatever it is at the level of each of the European education systems or from the point of view of the several international organizations involved in education and teaching, issues about the equity of the system haven't stopped increasing these last years. That is why it seems so important to rapidly secure the repetition of that work of developing indicators rather than to be satisfied only with the first results supplied by a "one-shot" action. The continuity of that work could not only take a systematic and totally innovative form, but also be integrated in some European structures already existing (specific work groups, Eurydice, etc.). Harmonized and well-thought data collections will have to be organized to this end, and they will be the result of a multi-collaborative work.

The authors of the present report did not want to adopt here a prescriptive perspective faced with the collected data. As a proof of the objectivity and the rigour of such a work, a descriptive analysis of the European educational systems running has been preferred, rather than a refined interpretation of the results and the building of recommendations which would unavoidably go over the strict frame of education research and development. Each member state is fully responsible for the content and for the organization of its own educational and training system(s), it is thus the privilege and the duty of each one to agree and respond to the various presented findings.

Lastly, even if the development of a pool of indicators aiming at managing and controlling an education system in relationship with verified information rather than with some unfounded perceptions or myths is a more democratic process and goes on increasing rapidly in the European educational systems, it is still important to make sure that every citizen can have an easy and complete knowledge of the collected information and of the way they are interpreted by their governments. Whatever they are teachers, parents, or pupils, it is essential that all of them can have access to them, even if the full understanding of the data requires a certain experience and sometimes an important investment. That is the reason why it seems important that the European institutions and the member states make sure together that the various indicators are available for a wide audience. The diffusion via the internet can represent a good solution, which has been adopted by the Commission.

Figure 1 .

 1 Figure 1. A common layout for each indicator.

  INTERNATIONAL WORKSHOP. Educational policies in Europe -Implications for equity/ equality, Örebro, October 9-11, 2003 Equity of the European Educational Systems. A Set of Indicators (European Group of Research on Equity of the Educational Systems) 7 A publication by the ad hoc group on equity issues (OECD) convened Geneva by Norberto Bottani and Walo Hutmacher (Hutmacher, Cochrane and Bottani, 2001) provided a first theoretical framework of indicators

Table 3 .

 3 Data sources of the 29 European indicators of equity.

A

system of indicators on the equity of educational system

	Inequalities	Inequalities	Individuals
	between	between	below the
	individuals	groups	threshold
	A.

Context of inequalities in education 1. Individual consequences of education

  -data on the personal and social development of pupils outside the field of civic education, for which we were able to use the IEA study "Civic Education" in a limited number of countries.Despite its relevance and the diversity of its subjects, the report, developed around 29 indicators, does not enable yet to fulfil the whole of the formerly designed framework. Those indicators do not always clearly answer all the questions related to the equity of the educational systems. If our indicators do not exhaust that very large research theme, the reason is that, despite all the information sources underlying them, a number of these sources are still useless, unavailable, or even non existing. The available data which were supplied by organisations depending on the European Union (Eurydice, Eurostat, etc.) as well as by other sources (OECD, International Association for the Evaluation of Educational Achievement -

	INTERNATIONAL WORKSHOP. Educational policies in Europe -Implications for equity/ equality, Örebro,
	October 9-11, 2003
	1. Disparities in income and access to employment	Luxembourg Income Study
		Public Funding and Private Return to Education
	2. Social advantages of education 1. Students' judgements on the equity of the educational	Shavit et Müller European pilot survey on sentiments of fairness at
	system	Labour Force Survey school
	Pisa 2000 2. Students' expectations towards the educational system European pilot survey on sentiments of fairness at
		IALS school
	3. Students' feelings towards justice in the educational 2. Economic and social inequalities European pilot survey on sentiments of fairness at 1. Inequalities in income and poverty system school Luxembourg Income Study 4. Index of tolerance / intolerance World values survey 1997 OECD / Pisa 2000 2. Economic security inequalities 5. Index of socio-political participation World values survey 1997 Labour Force Survey 3. Cultural resources 6. Index of trust in institutions World values survey 1997
	1. Level of education of adults 2. Cultural resources of 15 year-old students 6. Conclusions	UOE OECD / Pisa 2000
	3. Cultural practices of 15 year-old students	OECD / Pisa 2000
	4. Aspirations and perceptions
	1. Professional aspirations of 15 year-old students	OECD / Pisa 2000
	2. Students' criteria of fairness	European pilot survey on sentiments of fairness at
		school
	3. Students' general opinions about fairness	European pilot survey on sentiments of fairness at
		school

Equity of the European Educational Systems. A Set of Indicators (European Group of Research on Equity of the Educational Systems)

http://europa.eu.int/comm/education/programmes/socrates/observation/equality_fr.pdf (Version française)

" For to him who has will more be given, and he will have abundance; but from him who has not, even what he has will be taken away".(Matthew, Ch. 13:12)

Equity of the European Educational Systems. A Set of Indicators (European Group of Research on Equity of the Educational Systems)

The same kind of information related to non-EU States is available on the bottom of each the right page.

If needed, a more complete technical note is available in annex.

The lack of available data prevented us from calculating indicators that we nevertheless considered important.

Directorate General of Education and Culture (European Commission) under the Socrates number SO2-61OBGE. Six teams of researchers [Universities of Liège and Louvain-la-Neuve (Belgium), Burgundy (France), Rome (Italy), Cardiff (United Kingdom) and Madrid teams collaborated to prepare this report. The project was coordinated by the University of Liège -