A Context-Aware Middleware for Context Modeling and Reasoning: A Case-Study in Smart Cultural Spaces

Round 1

Reviewer 1 Report

In this paper, the authors present a new context-aware middleware for cultural smart spaces. The proposed middleware combines a generic context-aware ontology model, middleware and machine learning for context modeling and reasoning.

Overall, this paper is interesting and nicely structured. I think that the contribution herein introduced may have several and useful practical implications. The paper appears to be solid as regards its basic ideas, as well as it is written by using an appropriate technical language. The notation is clearly defined and consistently used within the whole paper.

 
Nevertheless, there is some recommendation that can be taken into consideration to improve it.

• The introduction section needs modification. The lacking features of existing context-aware reasoning approaches and the need for the proposed hybrid reasoning model.
• I recommend that the authors add a summary table after the related work subsections that compare all of the cited approaches based on their limitations. In this respect, in this table the authors should discuss the improvement and the differences between the proposed middleware and existing middlewares. This section must include recent work:

2020. Angsuchotmetee, R. Chbeir, and Y. Cardinale, “MSSN-Onto: An ontology-based approach for flexible event processing in Multimedia Sensor Networks,” Future Generation Computer Systems, vol. 108, pp. 1140–1158, 2020.

10. Mansour, R. Chbeir, and P. Arnould, “HSSN: an ontology for hybrid semantic sensor networks,” in Proceedings of the 23rd International Database Applications & Engineering Symposium, 2019, pp. 1–10.

2003. Gu, X. H. Wang, H. K. Pung, and D. Q. Zhang, “An ontology-based context model in intelligent environments,” arXiv preprint arXiv:2003.05055, 2020.

Alti, A., Lakehal, A., Laborie, S., & Roose, P. (2016). Autonomic semantic-based context-aware platform for mobile applications in pervasive environments. Future Internet, 8(4), 48.

• I advise authors to highlight the new concepts of ontology models in another color.
• The author has to include the details about machine learning layers used in network structure with precise formulas.
• The author has to include the details about reasoning rule engine used in in a Smart Cultural Heritage space.
• The authors has to include the deployment model details for context reasoning.
• The context reasoning will have the capability to interpret the user's context at runtime with the help of middleware in order to infer service’s actions and deploy the action components. However, this real time reasoning should be evaluated through the IEEE standard metrics like, network overload and network latency. This evaluation should take into consideration the complexity of the network and its scalability with MapReduce.
• In the evaluation section, it will be good to compare the proposed middleware with the existing similar middlewares in the literature's and based on their metrics.
• The author has to include the details about the implementation environment and tool details used for the proposed work.
• The results discussion and justification of the findings need to be improved and justified.
• The proposed contribution can open the theory to practical implementation that can give us the solution in realistic amount of time. What solution u propose to make the reasoning system real time and good scalability§

Author Response

We thank the reviewer for his/her evaluation of the manuscript and the issues raised. We took careful consideration of all comments and have revised many parts of the manuscript.

• Comment: “The introduction section needs modification. The lacking features of existing context-aware reasoning approaches and the need for the proposed hybrid reasoning model”
• A paragraph has been added in the introduction in order to specifically state the limitations of existing approaches and address the need for hybrid reasoning systems.
• Comment: “I recommend that the authors add a summary table after the related work subsections that compare all of the cited approaches based on their limitations. In this respect, in this table the authors should discuss the improvement and the differences between the proposed middleware and existing middlewares. This section must include recent work”
• A table summarizing the middleware developed in the context of Cultural Heritage has been added at the end of Section 2. The accompanying discussion about the improvement of the proposed middleware was also revised.
• The mentioned citations were added to the Related work in the appropriate subsections (2.2 and 2.4), apart from the fourth citation which was older (2003) and whose authors’ later work has already been cited in the original manuscript.
• Comment: “The author has to include the details about machine learning layers used in network structure with precise formulas.”
• Implementation details on the unsupervised learning method were added in 5.2 Machine Learning Module.
• Comment: “The author has to include the details about reasoning rule engine used in a Smart Cultural Heritage space.”
• Implementation details on the rule engine were added in 5.2 Rules Module.
• Comment: “The authors have to include the deployment model details for context reasoning.”
• At the beginning of Section 5.2, deployment details were added.
• Comment: “The context reasoning will have the capability to interpret the user's context at runtime with the help of middleware in order to infer service’s actions and deploy the action components. However, this real time reasoning should be evaluated through the IEEE standard metrics like, network overload and network latency. This evaluation should take into consideration the complexity of the network and its scalability with MapReduce.”
• The evaluation of the proposed reasoning scheme included the testing of representation, reasoning veracity and computational performance. Evaluation of network performance is out of scope. To further clarify this, we added an explicit mention of the scope of the evaluation in Section 5.3. Furthermore, we added the evaluation of network metrics as future work in Section 6.
• Comment: “In the evaluation section, it will be good to compare the proposed middleware with the existing similar middlewares in the literature's and based on their metrics.”
• Unfortunately direct comparison is not applicable, since performance and representation indices are acquired under a specific scenario with proprietary context data. There are no public repositories of IoT data which could be used by the community for comparison between proposed middleware.
• Comment: “The author has to include the details about the implementation environment and tool details used for the proposed work.”
• Details about the implementation environment were added in various parts of Section 5.
• Comment: “The results discussion and justification of the findings need to be improved and justified.”
• Section 5.3 discussing evaluation and results has been revised to justify the findings more accurately.
• Comment: “The proposed contribution can open the theory to practical implementation that can give us the solution in realistic amount of time. What solution u propose to make the reasoning system real time and good scalability”
• The relevant text in Section 5.3 about scalability has been revised.

Reviewer 2 Report

This paper presents a Context-Awareness Middleware for Context Modeling and Reasoning: A Case-Study in Smart Cultural Spaces.

The objective two main contributions are

- a context model which may be applied to define context in many scenarios with five core classes that represent the basic features of a context observation, namely thing, location, time, activity and reason.

- a hybrid reasoning technique applying specific reasoning techniques based on their suitability to address specific sub-problems.

The use case is then proposed with a middleware deployed in a cultural space. This use case explores the benefits of context modeling and hybrid reasoning in a scenario of preventive conservation.

The first main section is a related work section, presenting Context models, Context Reasoning Techniques, context aware middleware systems.

The second section initiates the core of the contribution. It focuses on context modelling. A meta-model is then introduced, presented and relations are explained. Then each high-level class is detailed.

The next part focuses on reasoning and presents an Architecture of context reasoning.

Then the papers starts on the presenting the case study on smart conservation of cultural heritage.

This paper is interesting. The context model is well described and justified.

The second part mainly focusing on reasoning lacks details. The section ‘middleware’ should be renamed Architecture as it is not a middleware is the “pure” definition of a middleware.

Author Response

We thank the reviewer for/her his overall positive assessment of the paper.

• Comment: “The second part mainly focusing on reasoning lacks details. The section ‘middleware’ should be renamed Architecture as it is not a middleware with the “pure” definition of a middleware.”
• Details about the reasoning process have been added in various parts of Section 5
• It is true that in this paper we are addressing only some of the functionality of middleware, since the focus is mainly on context modelling and reasoning. Nevertheless we have not used the term “middleware” in any section title, naming the sections as Related Work, Context Modelling, Context Reasoning and Case Study.

Reviewer 3 Report

This paper reads well and is presented in a logical structure with a clear narrative. I noted the references cited which include the majority of the usual published research into context-aware systems cited in many published studies into the topic. The paper is well presented with the materials and methods and results clearly stated along with clear figures.

The title refers to a CA middleware but reading the paper the primary focus appears to be on the development of an ontology (I have noted the modules described in the manuscript) designed to be both a simple data structure and a basis upon which reasoning (using a relatively simple rule-based system) may be achieved; the authors may wish to consider this observation.

I have comments:

1. I would recommend that the title (A Context-Awareness Middleware ... ) be revised to: (A Context-Aware Middleware ... ), the plurality is not grammatically correct)
2. I found that, while future work is referenced in the paper open research questions (including the issue of latency when considering generalisation of the proposed model) and potential solutions was not adequately addressed.
3. The concept of ontologies is essentially to enable generalisation across multiple domains and systems (the Semantic Web). However, I missed appropriate discussion on the semantic and linguistic issues that related to ontologies and how such problems may be addressed (in this respect the references may be improved)
4. The details relating to the development of there proposed ontology would be a very useful addition to the paper.

In summary, I found that the paper, while relevant on a practical level (the proposed focus of the paper?) provided limited novelty over previously published research into CA systems (middleware and ontologies). The paper is clearly of interest to the journal but the overall contribution to the research into CA systems is rather limited.

Author Response

We thank the reviewer for/her his overall positive assessment of the paper as “well presented with the materials and methods and results clearly stated along with clear figures”. 

• Comment: “The title refers to a CA middleware but reading the paper the primary focus appears to be on the development of an ontology (I have noted the modules described in the manuscript) designed to be both a simple data structure and a basis upon which reasoning (using a relatively simple rule-based system) may be achieved; the authors may wish to consider this observation.”
• Although a complete middleware has been implemented for the purposes of evaluation, it is true that in this paper we are presenting specific layers of the middleware, since the focus is mainly on context modelling and reasoning. Yet, we believe that the title should include the term “middleware” since it encapsulates the context-aware processing described in the paper.
• Comment: “I would recommend that the title (A Context-Awareness Middleware ... ) be revised to: (A Context-Aware Middleware ... ), the plurality is not grammatically correct)”
• We would like to explain the reasoning behind the title. Context-awareness is used as a noun to depict the functionality provided by the middleware. Context-aware as an adjective is better suited for an application which depicts that the application is aware of the context -- i.e. the middleware provides context-awareness functionality, which makes an application (utilizing the middleware) context-aware.
• Comment: “I found that, while future work is referenced in the paper open research questions (including the issue of latency when considering generalisation of the proposed model) and potential solutions was not adequately addressed.”
• The issue of latency and other network metrics were added as open questions for future work in Section 6.
• Comment: “The concept of ontologies is essentially to enable generalisation across multiple domains and systems (the Semantic Web). However, I missed appropriate discussion on the semantic and linguistic issues that related to ontologies and how such problems may be addressed (in this respect the references may be improved)”
• A reference on the Semantic Web was added to the Introduction.
• Comment: “The details relating to the development of the proposed ontology would be a very useful addition to the paper.”
• Details on the development of both the proposed context modelling and context reasoning techniques were added throughout Section 5.

Round 2

Reviewer 1 Report

    No further comments. Good luck 

Author Response

We thank the reviewer for accepting the revision of the manuscript.

Reviewer 3 Report

I have read the authors response and the revised manuscript including the additional content. I have comments:

1. I note the author response to the comment regarding the title (context-aware vs context-awareness. I fundamentally disagree and the observation regarding nouns and adjectives is grammatically and syntactically wrong. A middleware is "context-aware" not "context-awareness". It would be correct to state "the application of context-awareness to ... ". The title should be changed in my view to render is grammatically correct.
2. In all such research there will (as previously noted) ORQ which point to limitations and directions for future research with possible solutions considered. I note the additions to the conclusion but these fail to provide the information and detail required.
   1. I noted the funding: This research was co-financed by the European Union and Greek national funds through  the Competitiveness, Entrepreneurship and Innovation Operational Programme, under the Call “Research-Create-Innovate”; project title: “Development of technologies and methods for cultural inventory data interoperability—ANTIKLEIA”; project code: T1EDK-01728; MIS code: 5030954
   2. In all such funded projects ORQ and research directions are important in the reports - this detail is required.

In summary, subject to revisions for the above points the authors have addressed the comments made in my review.

Author Response

We thank the reviewer for his/her comments and the fruitful discussion on the title and future work. 

• Comment: “I note the author response to the comment regarding the title (context-aware vs context-awareness. I fundamentally disagree and the observation regarding nouns and adjectives is grammatically and syntactically wrong. A middleware is "context-aware" not "context-awareness". It would be correct to state "the application of context-awareness to ... ". The title should be changed in my view to render is grammatically correct.”
• The title has been appropriately changed.
• Comment: “In all such research there will (as previously noted) ORQ which point to limitations and directions for future research with possible solutions considered. I note the additions to the conclusion but these fail to provide the information and detail required.”
• A more detailed discussion on future work, including open research questions that will be addressed has been added in Section 6.