Implied Logic hosting proposition for eSTEM

30 November 2011

Sharing business models on the web just got one step easier.

If you don’t have the time or the inclination to set up or commission and manage your own web server, Implied Logic can host the implementation for you. We now have an ‘out of the box’ solution that can publish a generated, Flash web GUI for your models in a matter of minutes. (A generated HTML 5 alternative is under development to achieve wider device portability.)

By running the eSTEM software on our pre-configured and purpose-built infrastructure, the service will work straightaway, effortlessly extending your STEM application domain onto your colleagues’ or customers’ web-enabled devices with no expert IT involvement. User-registration (if not federated), usage tracking and error resolution are included in a fixed-price cost structure which removes the budget unknowns of an internal IT solution.

(Please see this previous article which takes A closer look at STEM models on the web.)

Hosted software configuration

Implied Logic will create a <your company> sub-domain within its own, professionally hosted server infrastructure and use this to run your chosen STEM models in response to suitable formatted and authenticated requests from remote web interfaces as generated by the forthcoming version 7.3 of the STEM desktop software. The software architecture looks like this:

Figure 1: eSTEM software architecture diagram

The software installation will be maintained exclusively by Implied Logic, whereas the offline folder where your models will be stored will be made accessible to nominated contacts via FTP. Implied Logic will manage the model-lookup and configuration files in the first instance, but these will be accessible via FTP too for when you gain the necessary expertise and confidence.

User registration

The simplest implementation makes models accessible via anonymous access without registration or authentication, but then the inputs offered would be limited to a current system ‘session id’ which could not be used to identify the actual user (or any pattern or consistency in their usage). Such a session id would expire after a matter of hours, with the effect that the model inputs would revert to default values for that user in their next visit after those hours had elapsed.

Therefore Implied Logic offers a registration system to which external users identify themselves by name, organisation, activity area and email address (which serves as user ID). The email address is verified by activating a login via a return mail with link. The system continually validates the email by sending a session-dependent login token to the login email at the start of each session.

However, you might prefer to use your own corporate customer-registration system, from which access to eSTEM could be ‘federated’ such that the registration and log-in process would be handled by your own system. This then avoids any data protection issues around Implied Logic gathering customer information on your behalf.

Tracking data

Details of the current user, date, time and uploaded model inputs are logged to a database for each model-run request handled by the eSTEM web service. To make it easier to benchmark the values provided by the users, the logging may optionally or additionally split the logged records by discrete input, depending on what kind of analysis is likely to be undertaken and actually useful.

The simplest approach stores a single record for each model run with all input values condensed into a single text field.

When (UTC) User Inputs
01 Jan 2012 17:00 Input 1 = 42.0; Input 2 = 88,112.0; Input 3 = 1.0; Input 4 = { 123.0; 456.0; 789.0 }
01 Jan 2012 17:08 Input 1 = 48.0; Input 2 = 88,112.0; Input 3 = 1.0; Input 4 = { 123.0; 456.0; 789.0 }
01 Jan 2012 17:12 Input 1 = 99.9; Input 2 = 99,999.9; Input 3 = 9.9; Input 4 = { 999.9; 999.9; 999.9 }

Figure 2: Example tracking data per model run

If it is desirable to analyse the range of values offered for specific, individual inputs, then the only scalable solution across a disparate selection of models is to store a separate record per input.

When (UTC) User Input Value
01 Jan 2012 17:00 Input 1 42.0
01 Jan 2012 17:00 Input 2 88,112.0
01 Jan 2012 17:00 Input 3 1.0
01 Jan 2012 17:00 Input 4 123.0; 456.0; 789.0
01 Jan 2012 17:08 Input 1 48.0
01 Jan 2012 17:08 Input 2 88,112.0
01 Jan 2012 17:08 Input 3 1.0
01 Jan 2012 17:08 Input 4 123.0; 456.0; 789.0
01 Jan 2012 17:12 Input 1 99.9
01 Jan 2012 17:12 Input 2 99,999.9
01 Jan 2012 17:12 Input 3 9.9
01 Jan 2012 17:12 Input 4 999.9; 999.9; 999.9

Figure 3: Example tracking data per input per model run

Additional columns could be added on reasonable request, such as name of saved model.


There are too many variables and unknowns – such as model size and complexity, reliability and speed of Internet connection, and number of contending users – to guarantee turnaround time for an individual model run request from an external front-end GUI. However, Implied Logic will ensure that correctly validated and authenticated model-run requests will receive fair processor allocation and that the time taken to run a model on the server itself should not exceed a factor of three times expected performance on a typical client laptop at the busiest times.

For an initial, single eSTEM server instance, the following limitations are expected and serve to define expectations for the scope of the service.

Metric Limit
Number of models 50
Disk space allocated for any webpages, Flash objects, model configuration files, original model files, per-user model files, per-user saved snapshots and tracking data 10 GB
Generic logins manually created by Implied Logic 20
Registered users created by automated self-serve procedure 10,000
Users per day 720
Users per hour 45
Concurrent sessions 15
Concurrent model runs 3
Nominated client personnel for support interactions 3

Figure 4: Service limitations

Immediate engagement with end users

Never has it been easier to share a business model – and the initial reception from our first customers for this service has been very positive indeed! Implied Logic has invested the effort to make it as easy as possible to make a STEM model accessible online. Not only is the experience immediate for the end-user (who has no proprietary software to install), but the hosting service itself can be demonstrated for free on and deployed within hours once a contract is agreed.

The scope, price and detailed terms and conditions of this hosting arrangement are available upon request, and we look forward to discussing how this service can work for you and your organisation.

© Implied Logic Limited