Web of Things: Understanding the Growing Opportunities for Business Transactions

Nikos Vesyropoulos

Department of Applied Informatics University of Macedonia 156 Egnatia Str., 540 06

Thessaloniki, Greece +30 2310 891880

nvesyrop@uom.gr

Christos K. Georgiadis Department of Applied Informatics

University of Macedonia 156 Egnatia Str., 540 06

Thessaloniki, Greece +30 2310 891869

geor@uom.edu.gr

ABSTRACT Building on the Internet of Things (IoT), the Web of Things (WoT) refers to a realistic and easily applicable idea of connecting an abundance of daily used devices and objects, such as embedded devices (smartphones, tablets etc.), through already well-established Web standards. Modern devices (which are usually equipped with sensors), have the ability to observe and monitor their environments. Consequently, there are unique opportunities and benefits to be reaped, by creating virtual counterparts, which allow access to their functionality through well-known protocols and standards (such as REST and HTTP). In this way, a corresponding digital world of vast resources is actually generated. Such opportunities can be of immense importance for business-centric scenarios where data provided and exchanged can complement and add to existing business models, thus playing an important part in the future planning of businesses.

In this paper we firstly attempt to highlight the current research approaches specifically from the view of business centric scenarios. We discuss current research directions as well as existing problems and challenges based on the WoT paradigm and its implementations. We also highlight the methods, techniques and architectures involved, especially from the perspective of Web Services interactions. We attempt to stress the importance and possible benefits of implementing WoT methods, in a number of different enterprise’s operations. We focus on a domain specific application, implementing the notions of the Web of Things on medium sized enterprises, such as a network of retail stores. Finally, we study the information provided by applying the WoT approach and we analyze the influence that this information has for the future planning of business procedures.

Categories and Subject Descriptors H.3.5 [Information Storage and Retrieval]: Online Information Services – Web-based services

General Terms Documentation, Design, Standardization.

Keywords Web of Things, Internet of Things, Web Services, REST, e-commerce

1. INTRODUCTION During the past few years, the notion of uniquely identifying things or objects through an RFID, Auto-ID Center or other techniques and thus introducing their virtual representations, has been a focal point in research. The paradigm of the IoT is mainly based on the aforementioned identification technologies, the transfer of data through wireless sensor networks, and the usage of embedded devices (such as mobile phones and smart sensors). The idea, introduced by the IoT, is that objects can be easily categorized and identified, resulting in them being connected over TPC/IP in a global network infrastructure [2]. That would enable communication between identifiable objects, while in parallel could often enable cooperation between them, towards fulfilling a common task. Such a network would provide vast opportunities for data to be captured, transferred or mined through the appropriate techniques [21]. The IoT is a promising research area, though difficulties and challenges rise due to the abundance of different protocols, implementations and incompatibility issues between application platforms [4].

The ideas introduced by the IoT can profoundly affect both consumers and enterprises [3]. Smart cars interacting with their environment and with the surrounding traffic, smart home appliances that would send information directly to the users phones and assisting ambient devices are only a few of the countless possibilities. On the other hand, enterprises can also benefit as the production line can be more efficiently automated, and waste management, logistics and various business processes can become more effective. More and more ideas towards this direction are constantly being presented, as a result of the interest that this topic has to researchers and industries [36].

In order to tackle the issues presented in the IoT paradigm, an emerging focal point in research has been the notion of the WoT, where well-known Web standards are used in order to enable the communication and interoperation between Web Services (WS) and real-world objects that can also provide operations and functions, as services. Based on the ideas presented in the notion of the IoT, the WoT takes advantage of the well-established

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Internet’s architecture and protocols, in order to facilitate a network of virtual representations of objects, heavily based on sensors and smart devices [6]. These objects, or things, would have a simple URL linking towards their virtual representation, as a Web page, occasionally giving access to services corresponding to the item in regard. Instead of the usage of WS based on WS-* specifications (namely, the WS star services, or WS-*), the notion of the WoT proposes the adoption of embedded servers based on the HTTP protocol and the trends emerging of the recent Web 2.0 paradigm [22]. As HTTP is used as an application protocol, the compatibility with the RESTful architecture is evident. By using URIs and a set of operational verbs (GET, POST, PUT, DELETE), the functionality of the service of the virtual representation can be accessed, and data and messages can be transferred to and from the things, usually in the format of JSON, Atom or structured XML. Thus, these representations can be accessed from any application that can handle HTTP requests, such as a typical Web browser.

2. SERVICE ARCHITECTURE FOR THE WEB OF THINGS During the past decade, many enterprises have shifted their focus towards the use of WS, in order to take advantage of the growing opportunities provided by the constant evolution and adoption of the Internet. Largely depending on the established languages and protocols provided in WS-* services, they have managed to integrate WS compositions to their business plans, and as a result they have reaped their benefits. Nowadays though, with the shift to the Web 2.0, there is a trend towards the adaptation and usage of the more flexible and scalable REST services. With the advent of the IoT and the WoT paradigms, the need to shift to RESTful WS is even greater as they are an integral part of the aforementioned paradigms. Nevertheless, WS-* services are still preferred for dynamic compositions in e-commerce transactions that require business level decisions (based on the orchestration and choreography of services) [28]. As WS-* natively support the BPEL and WSDL languages, negotiations are easier to perform.

While it is of great importance to create virtual counterparts for smart devices, and “things” which exist in the physical world, the true innovation in the WoT paradigm is in moving a step forwards: from just having a simple informative Web page for each individual thing or device, to the abstraction of WS provided from those devices discoverable and reachable through the HTTP protocol. In this way, “things” can be considered as resources exploitable by these WS. But the question that rises is which of the aforementioned WS architecture is preferable and better suited in fulfilling the needs in communication and interoperation between smart devices, and composition of value added services [11]. In order to facilitate the resolution of this concern we further analyze the two dominant paradigms.

2.1 Soap-based Web Services (WS-*) Also known as big Web Services, they are based on the exchange of messages through Simple Object Access Protocol (SOAP) envelops. SOAP, as a transmission medium, enables the interoperation of servers and clients based on remote procedure call (RPC) methods, through the exchange of structured, XML-based messages, using the HTTP protocol, or the Simple Mail Transfer Protocol (SMTP), as a transfer protocol. In order to reveal the operations provided by a WS and to describe its interface, Web Service Description Language (WSDL) files are being used. WSDL files describe the type of inputs allowed and

type of outputs expected, using parameters such as time parameters (current time and date, time that a service stays accessible), the general set of operations and effects that the invocation produces. All the aforementioned details are stored in a general registry where clients and services can discover them. The Universal Description Discovery and Integration (UDDI) standard provides the framework in which information for the services and their providers are stored as a sum of WSDL descriptions that can be discovered and accessed.

Among many others, WS-* describe a set of protocols regarding security issues (WS-SecurityPolicy, WS-Security, WS-Trust, WS-Federation, WS-Authentication) and quality of service (WS-ReliableMessaging, WS-Coordination, WS-AtomicTransaction, WS-BusinessActivity). SOAP-based WS are considered very reliable: they provide the means for asynchronous processing and offer the opportunity to exchange the current state of operations between the client and the service. Nevertheless, currently the trend is towards the stateless RESTful WS, partly due to the complexity of developing and monitoring SOAP-based Web Services.

2.2 Representational State Transfer (REST) Representational State Transfer (REST) is a service-oriented architecture for distributed systems [9]. REST defines specific architectural principles on designing WS, based on resources and their representations, allowing loosely coupled systems to interoperate. While resources can be every possible information, or concept, representations are the document or format that presents the resource or its current state.

A number of representations can be provided for a single resource. Most common representations are simple HTML pages, XML formatted pages and JSON files. Thus, the client can request a specific representation for a resource. An agreement on the appropriate representation is needed, to materialize clients and servers, and that is achieved through self-described messages. REST dictates that every message has all the information needed (such as the information of the desired media type, metadata about caching, error handling etc.).

The main idea behind REST is that services can be easily accessed through a Universal Resource Identifier (URI), and that the different states of the resources are exclusively addressed and transferred over HTTP, using specific HTTP verbs. Every RESTful WS, provides access to resources and their representations, through URIs. Unlike the UDDI repository provided in WS-*, clients can only identify and interact with services knowing their URIs.

In order for a service to be considered RESTful there are six constraints that the REST architecture style presents as requisites:

1) Client–server: Every REST-based system must be characterized by the separation of concerns. For example, data storage concerns only the server side. Servers on the other hand are not concerned with the user’s state.

2) Uniform interface: The interface for a component usually follows some generic rules. The above constraint is vital for portability and scalability concerns.

3) Stateless: Each request contains all of the information needed to interpret, to be able to service and to respond to that request. This has a profound impact on reliability and scalability. Session states are solely stored on clients.

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4) Cacheable: Servers allow responses to be cacheable or non-cacheable. The benefit is that clients cannot have access to former states when that could lead to corruption of data, but also reduce interaction when it is permitted resulting in improved performance, efficiency and overall scalability.

5) Layered system: In REST architectures the client can be directly connected to the server that services requests or to intermediates, without knowing it. REST architecture uses hierarchical layers of components, but each component can only interact to the one it is closest to.

6) Code on demand (optional): Code on demand is an optional constraint. Apart from data, servers can occasionally provide executable code to the client, with the most common implementations being scripts, mostly in JavaScript, or Java applets.

3. COMPOSING WEB SERVICES

3.1 Service Composition Soap-based and RESTful architectures differ significantly on how they manage the composition of services into value-added services for business processes. WS-* service compositions are based on the Business Process Execution Language (BPEL). It is an XML based language that enables the description of business processes. BPEL defines the interactions between services and the service composition engines. BPEL presents the invocation order and handles information regarding the state of a service. Additionally, it manages exceptions and describes the behavior of both executable business processes and abstract business processes. Compositions in WS-* services are accomplished through orchestrations and choreographies of services. Choreography is associated with negotiations and agreements between the business processes and the exchange of public messages and requires that all participants in the service composition have equal rights, while orchestration (which is mainly defined by BPEL), describes how services can interact, from the limited perspective of an end user [31]. In [33] a formal definition of the BPEL execution semantics is presented based on the BIP component framework.

On the other hand, RESTful service compositions are usually handled as Web 2.0 mashups. A Web mashup, is a Web application or a Web page which usually uses application programming interfaces in order to blend information from multiple sources to create compelling services. This is accomplished by composing data and services from a number of sources and presenting them as value-added services. Nowadays, more and more Websites provide APIs, thus allowing programmers to integrate the services and data provided, into another set of data to create larger-scale services. Mashups are considered to have played a pivotal role in the shift towards the Web 2.0 paradigm.

While Web 2.0 mashups are considered popular method for the composition of RESTful WS [10], other alternatives exist. It is possible to create value-added services using an extension to BPEL (proposed in [29]) or through the use of JOpera tool [30],

which is an eclipse plugin. JOpera is indeed a promising alternative, although it is in fact a remote procedure call-oriented in nature tool.

3.2 Compositions in WoT-based scenarios As more and more embedded devices (like smartphones and sensor equipped appliances) will be apply to provide their functions as services online, and an abundance of real objects will essentially become a part of ambient spaces (AS) (interoperating and communicating over TCP/IP networks), the need to create value-added services by composing numerous embedded-device enabled services, including if possible traditional WS, is growing exponentially. A constantly increasing concern of researchers was the inability to integrate services provided by the ever increasing number of smart devices. As platforms, protocols and services greatly vary, there is a need to handle smart devices as loosely coupled systems. With the usage of the HTTP protocol as an application protocol, the aforementioned need is supported.

But not every device is able to understand and transmit HTTP requests. The solution is provided by small sized servers that can allow devices to wirelessly transmit data, thus essentially allowing them to publish their functions as WS. To facilitate this, two methods exist: the first is to integrate the Web server into the device, enabling it to natively support TCP/IP networks and to be able to easily publish its functions as RESTful APIs. However, as the cost of equipping all physical objects or devices is high, a more feasible alternative is to equip a network of “things” with a proxy, called Smart Gateway, which acts as an intermediate Web server [35]. The proxy is responsible for the interoperation with the devices, based on the specific protocols used by the devices. The communications between the devices and the Smart Gateway is accomplished through wireless Bluetooth technology. The Gateway is responsible for the translation of messages to HTTP requests and vise-versa, and consequently acts as a medium for the communication of the device with the Web by the usage of a unified RESTful API.

While the business rules that can be handled using SOAP-based WS are a compelling feature, in order to create a value added service in WoT scenarios (where HTTP is used as an application protocol), the most common practice is the usage of Web mashups, described above. The main difference lays in the fact that not only Web-based services can be part of the composite service, but services provided by embedded devices can also be involved in mashups.

3.2.1 Physical-Virtual Mashups These mashups regard the composition of services provided not only from traditional Web-based services (virtual services) but from services provided by embedded devices and physical objects in the real world. Physical services enable enterprises, end users or other smart devices to interact with the embedded devices by sending HTTP requests (such as GET to receive information about the status of the device or associated objects, or POST, PUT, DELETE to change its status). While these are well received conveniences, more compelling services can be provided by the composition of physical-virtual services in mashups where for example information regarding energy consumption in various appliances in an enterprise can be presented on a map directly received by the RESTful API provided by Google for the Google maps application. Thus managers will be able to visually monitor the activity captured by sensors and react quickly to malfunctions or threats.

3.2.2 Physical-Physical Mashups Such mashups are created by composing functions provided as services solely by embedded devices with data provided by real world objects. Sensors can communicate through Smart Gateways, without the need for programmers to develop deep

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knowledge on their architecture, as all functions can be accessed through direct HTTP calls. Applications of such mashups include the cooperation between sensors in the production line of enterprises, where for example the increase of temperature in a specific manufacturing machine can result in a message exchange between the machine and the air ventilation and air condition management systems, and to an executive employee for monitoring purposes. In result, the ventilation system will focus on the cooling of the specific machine while it will lower energy consumption in other sections of the production line so that energy consumption will not increase. In both scenarios, specific mashup tools exist in order to facilitate the interoperation of smart devices and virtual WS. An indicative example is Yahoo Pipes, a popular Web application for mashups, (illustrated in Figure 1), while other alternatives such as the firefox plugin Clickscript is also a very easy to use and powerful mashup tool. By using Yahoo Pipes, developers provide users the ability to filter specific information regarding data from raw QR-tagged objects or sensors. Based on preferences, users can include for example information from nearby sensors and maps into a mashup, presented directly to their smartphone (provided they have an internet connection).

3.2.3 Business Intelligence Mashups Business Intelligence Mashups regard to web application that effectively integrate a number of their own business-specific local applications and information with resources provided by external WS, in value-added services. In order to achieve Business Intelligence Mashups, occasionally Business logic semantics should be involved into the composition, resulting in the need of BPEL-based orchestration and WS-* protocols. It is crucial to consider a dynamic adaptation to arising user needs and requirements in real-time. In more detail, available WS should be added, altered or removed dynamically in order to respond to the rapid business-environment changes and QoS requirements.

Business intelligent mashups are described in [15], using a set of standards established for tracking and discovering RFID-tagged objects and goods in supply chains, known as the Electronic Product Code (EPC) Network. An EPC Information Service (EPCIS) enables discovery of RFID events through WS-* services. Nevertheless, through the translation proposed, EPCIS

WS-* interface can provide RESTful services, resulting in both embedded devices and raw RFID-tagged objects to be handled through EPCIS, that plays the role of a Smart Gateway. We find this approach very promising, as it enables Web applications to query for tagged objects directly using the uniform HTTP interface. The EPCIS framework in turn, translates the RESTful requests into WS-* calls [16]. A differentiated approach, described in [18], is the offering of high level public interfaces, such as API’s and easily adjustable widgets to the end users, in order to provide them the opportunity to create and compose flexible mashups, that correspond to their personal needs, without the need of assistance from the IT department. Enterprises that provide such conveniences to end users gain can benefit from the abundance of refined mashups that can be created, which apply to a plethora of customer needs, without much effort.

4. RELATED WORK WS allow loosely coupled components, to communicate and exchange vast amount of data, while they provide the means to include business logic in service orchestrations through semantics integration. Thus, they provide the means to enforce scalability and interoperability in a plethora of applicable areas, while in addition they are a well accepted standard in WoT scenarios. So, in our opinion they outperform other related similar approaches. Nevertheless, while the WoT promises state of the art, and pioneering solutions, many challenges rise, which are tackled in recent research topics, regarding the discovery of physical and virtual WS, the effective and efficient interoperation of smart devices and real world objects and the composition of Web mashups to provide enhanced Web applications.

Stirbu et al. in [34], propose an approach for integrating devices to the Web, through REST principles while focusing on the discovery of services created by embedded devices, while in [12], a set of requirements are presented for the efficient querying and discovering of services that can be applied to virtual services as well as services from the function of physical objects. Those include the Minimal Service Overhead, Minimal Registration Effort, Support for Dynamic and Contextual Search and Support for On-Demand Provisioning.

Figure 1. Yahoo Pipes: enabling the virtual-physical mashup.

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Guinard et al. in [13] describe an interesting application of the WoT notions, as they present a schema of home appliances creating a mashup, presenting their energy consumption, giving users the ability to monitor and lower their energy demands, based on Smart Gateways. On the other hand, Akribopoulos et al. in [1] present an architecture of smart objects that expose their functions as WS, without the need of Smart Gateways. This is a compelling approach, since the sensor-equipped devices can instantly issue HTTP-based requests, though the exchange of messages is more complicated.

Duquennoy et al. in [7], [8] present Smews, an embedded Web server to enable the transformation of physical objects to service

providers, providing support of multiple in-flight packets while handling several simultaneous TCP connections. In a nutshell, they describe efficient tiny embedded Web servers that request minimal volatile memory.

Guinard et al. in [14] attempt to formalize design parameters, and illustrate how applications can be built on top of the RESTful oriented architecture.

Ostermaier et al. in [27] demonstrate the appliance of well-known Web infrastructures in publishing services and data by sensors and objects. They present Dyser, a real-time search engine for the devices, capable to find real-world entities, based on the state they exhibit during a query.

Mayer et al. in [24] illustrate the use of a semantic discovery service for Web-enabled smart things, named DiscoWoT, which allows users, to dynamically alter the method of finding representations of resources at run-time. On a different perspective, Zhong et al. in [39], propose the notion of the Wisdom Web of Things based on the data cycle, namely “from things to data, information, knowledge, wisdom, services, humans, and then back to things”, to allow harmonious interaction between human, societies, and smart things.

5. WEB OF THINGS POTENTIALS Using the technologies behind Web 2.0, users can monitor properties, and information, regarding products, and appliances [32]. The idea of smart cars that would provide information and updates about their status, to an email client or through an RSS feed is a compelling capability [25]. For example, information regarding the oil levels and the brakes’ status can be constantly sent to the owner of the car, by the car itself. Additionally, information regarding the traffic around the car, along with the predicted weather conditions and the traffic lights status can be dynamically created and presented through a mashup, on a map, to the GPS monitor of the car. Thus, it is clear that data can be dynamically composed and send between smart objects, and the end user. The ability to compose value-added services, based on the well-known online WS and the services provided by the virtual representation of objects is a very significant characteristic. The most common WS used in such scenarios are related to Google maps. Through an API, these WS allow developers to compose services that depict certain information regarding objects, or readings on sensor on a map provided by Google. In this way, they provide a visual interface, instead of presenting for example plain text containing simple sensor readings.

An alternative to this is the mashup of data provided by smart home appliances, using embedded sensors and WS in order to provide energy-consumption information to the house owner in her browser or directly to her email or smartphone. This could

lead to an overall reduction of wasted energy [19]. But the notion of the WoT is wider as additional sensors could respond to movement and regulate additional parameters (for example heating and air cleaning). If all those sensors were connected and if they could wirelessly communicate and interoperate based on a proxy gateway, significant benefits could be obtained [17].

An additional capability provided by the significant evolution of smart phones is that GPS–based user tracking can be accomplished. This capability could be highly enhanced by wireless sensors and information provided by the phone service provider. Additionally, it could enable the creation of a Web mashup based on interior maps, and a data stream provided by the corresponding service provider. Based on the precise location of a customer on a retail shop, additional and spot-on information can be dynamically provided to hers mobile device. In the case of an enterprise, we may consider for example the opportunity to enable specific discounts and offers to customers visiting a specific sector of a retail store or to customers being near the cafeteria. In addition, information regarding related products to the ones she is near to, or advertisements about offers in the store, could be presented as hotspots on the map through the Web mashup.

Furthermore, based on specific tariffs, agreements and relationships between stores, when a customer is within a specific store in a mall, advertisements and premium offers could be directly announced through her handheld device, concerning another retail shop of the mall, which maintains cooperation with the shop she is currently visiting [37]. The possible applications of the aforementioned applications can be easily expanded to support the needs of museums or exhibitions, in the sense of creating dynamically information regarding specific exhibits and delivering it to visitors. Handheld device manufacturers, and map providers such as Apple1 are currently headed towards the integration of such services in future releases of their operational systems and map services.

6. CASE STUDY In recent research, many efforts have been made to provide customers-clients with solutions based on the principles of the Web of Things. Since smartphones are more and more affordable, it is reasonable that many efforts focus on the implementation of Android and IOS applications [20]. The goal is to enable users to share experiences, evaluate and get informed about products [23], [26]. In our opinion it is of the outmost importance for every aiming-high enterprise to develop its own suite of WoT-based applications that would simultaneously provide assistance, references and recommendations to end users and a constant information stream to the enterprise. In our work we attempt to shed light on the way individual components interact and interoperate, in an easily applicable WoT scenario, and how the notions of WoT can be enhanced by adjustable business intelligence-based applications.

6.1 Customer-Centered Services An Android and/or IOS application can be provided for free to customers. Ideally it could even replace the common practice of membership cards, relieving customers of the need to constantly carry such cards for a plethora of stores. The application, if the customer allows it, will provide information to the store,

1 http://slashdot.org/topic/bi/apple-acquires-wifislam-for-indoor-

maps-report/

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regarding the customer, her past purchases and even information about the products she has checked online. The application will include QR recognition abilities, through the deployment of the smart phone’s camera sensor. As a result of the radical evolution of smartphones, modern devices are usually equipped with high performing camera sensors, commonly exceeding 5 MP resolutions.

Customers can easily scan the QR on products resulting in the immediate loading of the product’s page on their smartphone. In parallel, as product selves are equipped with servers and through the usage of wireless communication the position of similar products in the store can be revealed to the end user. After the initial scanning of the QR code, the application sends a query, containing identification data, to a WS, which returns the product’s page. Information regarding the product, user’s feedback and rating and direct links for the uploading of the data to social networks are well received features. Through these social networks, users can share their experience about a product, and have access to the product’s evaluation and feedback from other users. Ideally if the product has been purchased by a familiar person to the end user, the application could support the direct request for a review by that person. Recommendations are also a key feature that would provide additional value to the application [5].

What we find that could be extremely important for the management of a retail store, is the comparison of data received by the scanning of QR codes to the actual purchases of these specific products. If the comparison of data shows a large difference between the number of times a product has been examined by customers and the number of products sold, that could lead the store to the assumption that the product is not properly marketed, or that there are key characteristics in that product that attract the attention of customers but maybe not for good reasons, or that those characteristics are not strong enough to turn the product into a compelling purchase. Such information can be invaluable to an enterprise and in our opinion is something that should be used in addition to existing business models, often in a complementing role. Since the aforementioned allows the enterprise to monitor client trends and behavior, and to receive information based on the location of the users, the enterprise receives an invaluable, data set that could have a profound affect in future strategic marketing

6.2 Enterprise-Centered Services However, the real opportunities growing with the WoT notion are coming from the ability to seamlessly and dynamically combining data from various sensors, embedded devices and raw materials that provide functions as WS. We propose that enterprises should integrate sensors and Web servers in various sections of their business activities.

To name a few, information regarding the availability of products, automatically provided by sensors installed in the storage can enable the automation of orders and resupplying. When the smart gateway no longer detects the presence of a certain cargo (through Bluetooth activity), an immediate signal is sent to the ordering service, while it is recommended that those signals should be approved by authorized personnel, before the order is actually committed. In [38], an alternative framework is provided for the identification of RFID tagged materials and the automation of the supply chain. Additionally, information regarding the temperature and moisture in the storage room, captured by the appropriate sensors, could prevent damage to the products, thus it can result in less wastes, while in parallel such sensors enable the optimal

operation and cooperation of ventilation, heating and other affiliate systems resulting in optimal energy management.

6.3 Smart Basket In our case study, we introduce the Smart Basket: a basket that is equipped with a Smart Gateway and can communicate and transfer information back and forth sensors in various sections of the store, through Bluetooth wireless message exchanges and by bridging the requests from and to the TCP/IP. The Smart Basket (which is depicted in Figure 2), can keep tab of the QR-tagged products, either through the scanning of the QR-codes by the smartphone of the user or by an embedded scanning device. Information regarding the total cost of the products and their expiration date will be forwarded to the end user (customer). Additionally, by reading signals from sensor equipped appliances in the retail shop (such as fridges or even from shelves or sections of the store with simple Web servers), information regarding the temperature of products, their availability, the expected date of the arrival or replenishing of specific products can be transferred to the customer. Data received from a GPS sensor on the basket with the addition of data received from sensors in the store, could provide accurate location information that could present to user a mashup of an interior map, dynamically created offers based on her transactions and preferences. Recommendations could easily also be provided.

Such mashups can be further enhanced by providing information, recommendations and reviews from social networks by linking the customer accounts with the aforementioned mobile application. But since the customer is moving in the store, there is a need for sensors to be dynamically discovered and identified by providing their URLs. This requires a constant exchange of messages from and to sensors. When TCP/IP requests arrive at the Gateway (the Smart Basket’s Web server), these requests are forwarded to the set list of currently enrolled sensors and vise-versa, thus providing their functions as accessible services. HTTP verbs such as PUT and DELETE enable the interaction with smart devices to update or remove information regarding specific products.

In addition, as mentioned above, customers can be provided with public interfaces, such as API’s and widgets, which will allow them to retrieve information that matches their needs. For example, customers may not be interested in the conveniences provided by GPS sensors, or furthermore they may feel their privacy intruded in case their exact position in the store is monitored. Thus, adjustable mashups through the Android application may give them the opportunity to filter data streams according to their own needs, while at the same time can provide valuable information to the retail store.

Figure 2. Smart Basket interoperability.

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Another convenience provided by the Smart Basket would be the automated calculation of the total costs of the products, with the ability to include offers, discounts from coupons or the exchange of points into the calculation. As a result, the customer could avoid the long lines in cashiers, and instead opt to pay in an automated selling point, or through e-banking by connecting from the Android/IOS application to hers e-banking service. Of course, many security concerns rise from such a transaction, like identity theft or attempts to exploit bugs by the users themselves in order to deceive the system. Nevertheless, applications that allow users to bypass waiting lines and spare time, could prove to be the competitive advantage for enterprises, especially in modern times that are characterized by fast paces. Such business opportunities need to be exploited by enterprises, and since the WoT notion provides the means, it’s up to them to harvest the benefits.

7. CONCLUSION In this paper we offered an indication of the WoT notions, stating the growing opportunities provided especially for business transactions. After a brief overview of current research concerns, and challenges that rise, we analyzed the different WS architectures that play a pivotal role in the composition of compelling services. We examined the methods and techniques for the creation of value-added compositions, especially through Web mashups, containing services provided both by virtual WS and from smart objects providing their functions as services. Finally, through a use case scenario, we attempted to present how the means provided by the WoT paradigm can offer an enhanced interoperability between different sectors of an enterprise both for monitoring and managing operations, and for providing conveniences to the end users.

We strongly believe that the development of a network of embedded devices can provide the enterprise and its customers conveniences as well as state of the art tools and capabilities. It certainly allows businesses to have a competitive advantage in their individual domain. To illustrate that, we presented a domain specific scenario of enhanced services through mashups in a network of retail stores.

Nevertheless there are always complexities involved when adopting new technologies or techniques, especially when an enterprise has to adapt them into current systems. While an abundance of mashup tools exist, it is not always easy to include the notions of WoT in real life scenarios. Advanced knowledge involving embedded systems and sensor integration are required while Business Intelligence is also a major concern. Enterprises should carefully plan their business model in advance in order to reap the benefits of applying the WoT notions in their operations.

Future research includes the implementation of the Smart Basket in real life situations, to enable the evaluation of its features both for the end users and for the measurement of the value of its contribution in the developing of business plans for enterprises. By comparing results in a plethora of different domains, deductions can be produced, on how significant the use of WoT notions can prove to be in each domain. A final outcome of such case studies analyses could eventually reveal well-defined and easily applicable evaluation criteria, capable to assess the suitability of utilizing the WoT notions in various domains.

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