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Abstract:The so-called smart factory is a novel paradigm that is rapidly gaining ground in scenarios for factories of the future. Many manufacturing companies try to raise the level of smartness by considering a number of aspects related to the smart factory. However, there is a lack of field-oriented systematic research to help them fit the interest of industry for promoting interest and diffusion of smart factory. Moreover, it is still difficult to assess whether the vision of the future factory that incorporates information and communication technologies is implemented. Therefore, in this study, we propose a smartness assessment framework for smart factories which is based on the concept of operation management so as to be easy to make manufacturing companies to understand and apply. The framework is composed of evaluation criteria and sets the weightings of the criteria using analytic network processes. From a case study based on 20 small and medium-sized manufacturing enterprises, the effectiveness of the proposed framework has been verified.

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Geographic routing has been considered as an efficient, simple, and scalable routing protocol for wireless sensor networks since it exploits pure local location information instead of global topology information to route data packets. Geographic routing requires the sources nodes to be aware of the location of sinks. Most existing geographic routing protocols merely assume that source nodes are aware of the locations of sinks or can get the locations of sinks by some service. How can source nodes get the locations of sinks was not addressed in detail. In this paper, we propose a Circle Path Based Sink Location Service for Geographic Routing in wireless sensor networks. In this scheme, a source node sends a Sink Location Query (SLQ) message to the predefined Base Node and sends another SLQ message to a node on the edge of the sensor network, thus generating a SLQ path; a sink node sends a Sink Location Announcement (SLA) message along a circle path, the centre of the circle path is the predefined Base Node. By this way we can guarantee the SLQ path and SLA path have at least one crossing point. The node located on the crossing point of the two paths informs the source node the sink location. How to achieve this procedure in any irregular profile sensor network is another challenge of this paper. Simulation results show that our protocol is significantly superior to other protocols in terms of energy consumption and control overhead.

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A wireless sensor network typically consists of users, a sink, and a number of sensor nodes. The users may be remotely connected to a wireless sensor network and via legacy networks such as Internet or Satellite the remote users obtain data collected by the sink that is statically located at a border of the wireless sensor network. However, in practical sensor network applications, there might be two types of users: the traditional remote users and mobile users such as firefighters and soldiers. The mobile users may move around sensor fields and they communicate with the static sink only via the wireless sensor networks in order to obtain data like location information of victims in disaster areas. For supporting the mobile users, existing studies consider temporary structures. However, the temporary structures are constructed per each mobile user or each source nodes so that it causes large energy consumption of sensor nodes. Moreover, since some of them establish the source-based structure, sinks in them cannot gather collective information like mean temperature and object detection. In this paper, to effectively support both the remote users and the mobile users, we propose a novel service protocol relying on the typical wireless sensor network. In the protocol, multiple static sinks connect with legacy networks and divide a sensor field into the number of the multiple sinks. Through sharing queries and data via the legacy networks, the multiple static sinks provide high throughput through distributed data gathering and low latency through short-hops data delivery. Multiple static sinks deliver the aggregated data to the remote users via the legacy networks. In case of the mobile users, when a mobile user moves around, it receives the aggregated data from the nearest static sink. Simulation results show that the proposed protocol is more efficient in terms of energy consumption, data delivery ratio, and delay than the existing protocols.