FoT-Rules: A Semantic Rule-based Approach for Smart Spaces Through Fog of Things

Tracking #: 2282-3495

Cleber Santana
Brenno Alencar
Ernando Batista
Cassio Prazeres

Responsible editor: 
Guest Editors Sensors Observations 2018

Submission type: 
Full Paper
Smart Spaces or Smart Environments are related with ubiquitous computing in the sense those sensors, actuators, and others computational elements should be embedded seamlessly in the everyday objects. In the Internet of Things (IoT), Smart Spaces will enable environments to adapt according to people (users) needs by using smart and connected objects. However, to turn the IoT view into a reality, the users should know about technical details of such objects, which is not a trivial task for most ordinary users. Therefore, this article presents FoT-Rules, an approach for the construction of semantic rules aiming to create Smart Spaces through Fog of Things, which is a paradigm for Fog Computing in the Internet of Things. FoT-Rules is designed to enable ordinary users to create semantic rules in the Event-Condition-Action standard (ECA) and to take actions according to the environment at the edge (Fog) of the network. In this work, we present a scenario where the user can create semantic rules in the ECA standard. In order to create these rules, FoT-Rules provides the following functionalities: (i) creation of semantic rules; (i) obtaining of the semantic model that contains information related to an IoT device; (ii) execution of a semantic reasoner over the semantic model according to the rule created by the user; (iii) providing of a semantic observer that is responsible for observing changes in IoT devices; and (iv) in case the rule created by the user is activated, an action is taken for an IoT device. Finally, we performed four types of evaluation on our FoT-Rules approach: reliability, efficiency, scalability and usability.
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Reject (Two Strikes)

Solicited Reviews:
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Review #1
Anonymous submitted on 14/Oct/2019
Minor Revision
Review Comment:

Authors addressed most of my points in the revision. My opinion about the paper is more positive than the initial submission since I think the presentation of the work has been improved. However, some of the major comments I’ve previously made aren’t undertaken:
1 - I still think (especially the first paragraph of) the introduction needs some massaging
1.1 - The listing describing the benefits of a semantic-based representation model is not well-formulated:
1.1.1 – why “modularity” and “reactivity” are under “expressivity”? none of these concepts (modularity, reactivity and expressivity) make any sense from this paragraph.
1.1.2 – what is “information hiding”? the paragraph supposed to describe information hiding only talks about sensors’ collecting data and inferring knowledge via rules.
2 - All the figures are bitmap images and therefore especially some of them (e.g., among severe ones Fig. 6,8,9,10, and 11) does not scale well. I strongly suggest the authors to rework all the figures as vector images and to provide a visually appealing and consistent style. You can recreate these figures easily using an online tool (e.g., drawio) and include these figures as “vector” graphics (e.g., in the form of pdf).

Other comments:
- There are couple of sentences written in Portuguese in Page 18!!
- Page 6, subsection 3.1: SOTF-IoT → SOFT-IoT
- Page 15, figure 7: The figure header is redundant and can be presented in the caption.

Review #2
Anonymous submitted on 24/Oct/2019
Review Comment:

The paper has been improved significantly compared to the previous version. In future, the authors should prepare a response letter and highlight the sections that they have changed/extended to make it possible for the reviewers to follow the responses to the recommended changes.

Overall, the paper is suitable to be published in the journal. Only one change is recommended. In the title “Fog of Things” does not reflect the nature of the work. The authors are recommended to change it to either “edge computing” or “in a Fog Computing Architecture” or something similar.

Here are some general recommendations regarding the paper and future work:

- Please make sure your work if possible linked to a real-world problem and something that an easy fix will not work. This is a nice work but one can think how much it could apply to real-world scenarios when complex functions are performed. For example, state machines and access control and deadlock prevention and/or fault tolerance (which can be an issue in real-world IoT application) are important issues that are not discussed.

- For such system usability and flexibility of the rule editing and publishing a new set of tasks are always important. While user study is not the focus of this work, some form of study to show how this work can apply to users in a field would have been helpful.

- The interaction between a higher-level Rule System and lower-level IoT devices would be a key challenge to the scalability of such a system. The authors could also consider abstraction layers and message/command abstraction for common forms of IoT platforms and system to create an environment that different systems can be added and interact with each other. Programming interfaces and standard method could become part of such a work to allow other third-party developers to add their own devices and control them using the existing rules.

Review #3
Anonymous submitted on 06/Nov/2019
Major Revision
Review Comment:

The paper proposes FoT-Rules, an approach based on semantic rules built into the ECA format to support end-users on the creation of Smart Spaces at the edge of the network. FoT-Rules is an extension the Fog of Things (FoT) paradigm proposed by other authors for designing and implementing Fog Computing platforms for the Internet of Things.

The overall approach presented in the paper is still very interesting and original also in this revised version, but, even if the paper is improved a lot in its presentation, the manuscript is still confusing and not so clear. The flow of the paper has been improved and now is easier to follow the concepts explained thoroughly the manuscript. Concepts and elements have been better explained and presented, but some indications given in the first review have not been followed.

A running example, or some other specific examples, throughout the paper would help the reading for sure.

Despite the 1st review indications, even in this second version the manuscript addresses semantic rules in ECA standard for a single device and refer to smart space, but an explanations about the orchestration of the different devices is still missing.

Reported evaluation are still trivial and lacking. Table 2 collects some results, but they are not described and explained in deep. Table 3 and 4 are not enough to show and explain a sample sets and a configuration.

I’m still convinced about the validity of the approach. The manuscript improved a lot, but it cannot be accepted in the current status. The authors should follow the reviewers’ suggestions.

Concluding, the originality of the paper is valuable, significance of the results need to be better reported, and quality of writing is now improved.