Yi Zhi Zhao

A survey and projection on medium access control protocols for wireless sensor networks

Recent advances in wireless communications and sensor technologies have enabled the development of low-cost wireless sensor networks (WSNs) for a wide range of applications. Medium access control (MAC) protocols play a crucial role in WSNs by enabling the sharing of scarce wireless bandwidth efficiently and fairly. This article provides a survey of the literature on MAC protocols for WSNs. We first briefly describe the unique features of WSNs. We then review representative MAC protocols from the following four categories: contention-based protocols, contention-free (scheduled-based) protocols, hybrid protocols, and preamble sampling protocols. Our discussions focus on the background, main features, operation procedures, major design issues, and the advantages and disadvantages of these protocols. We also present an analysis of the inherent and desirable features of the protocols, and the key challenges of MAC technology for WSNs. Finally, we present our view on future research directions for WSN MAC protocols in a reader-friendly way using illustrative diagrams.

Model-based fault diagnosis/prognosis for wheeled mobile robots: a review

This paper presents a survey on model-based fault diagnostics and prognostics for wheeled mobile robots (WMRs). Numerous cases of faults diagnosis and prognosis solutions show that, for a complex machine like a WMR, model-based methods that utilize analytical models of the system are desirable because analytical models can well represent the nominal behaviours of the system. On the other hand, data-driven methods are not practical for WMRs since they require a lot of failure cases and data that are too costly, if possible at all, to obtain. Fault prognosis for a system in general and for WMRs in particular is still at the preliminary stage. System models can also be used to predict the remaining useful life of the system.

Data management for wireless sensor networks: research issues and challenges

Wireless sensor networks (WSNs) as the basic infrastructure for pervasive computing environment are data-centric in nature. The research issues and challenges relating to sensor data management are much different from those of traditional database and wireless communication. This paper presents a concise review of the latest technologies, research issues, and challenges facing data management for WSNs.

Distributed Design of RFID Network for Large-Scale RFID Deployment

It is no doubt that RFID technology is of very widespread applications. With RFID deployment scales-up, its application becomes more and more network-centric. The design of RFID network hence plays a critical role for successfully deploying large-scale applications. This is especially true when the tagged object is on item-level. This paper discusses issues that should be considered in design of RFID network; analyzes the potential impacts of different RFID network design on the existing enterprise network; presents a distributed design of RFID network for large-scale deployment. The paper also quantifies packet size of RFID data based on EPC serialized number; analyzes bandwidth requirement of RFID traffic for the diversified number of readers to illustrate the necessity of the distributed design, which authors believe are helpful for the earlier adopters of RFID technology, and may ignite more researchers and pioneering practitioners involving R&D along this direction. As a case study, the paper presents a cost-effective, sound and efficient RFID network design for retail.

An Energy-Efficient Self-Adaptive Duty Cycle MAC Protocol for Traffic-Dynamic Wireless Sensor Networks

A plenty of Medium Access Control (MAC) protocols deal with static traffics with low traffic load. The performance of these protocols drops significantly when network traffic become dynamic or in high traffic load. In this paper, we propose a new MAC protocol called Self-Adaptive Duty Cycle MAC (SEA-MAC) by introducing dual adaptive mechanisms: (1) An Adaptive Scheduling (AS) mechanism which makes the nodes’ active duration adaptive to variable traffic load, thus enabling SEA-MAC to resiliently schedule data transmission for the Sleep period. The algorithm is designated to schedule more data transmission in bursty and high traffic load, thus enabling rapid dissemination of data and reduction of latency. While under the light traffic load, nodes enter the Sleep mode timely, mitigating idle listening and saving energy. (2) A Self-Adaptive duty cycle mechanism which further adjusts the duty cycle and makes SEA-MAC adaptive to the dynamic traffic loads. When network experience with very low or very high traffic load, the protocol further adjusts duty cycle dynamically based on the traffic load, thus reducing inefficient duty cycle or reduce end-to-end delay. Experiment results show that the SEA-MAC is a great advancement compared with AS-MAC and RI-MAC protocols on the performance for unicast scenarios, especially under heavy unicast traffic load. SEA-MAC can reduce average and max end-to-end delay up to 50.90 and 68.20% respectively, lower energy consumption up to about 16.28%, and increase PDR up to about 16% compared with AS-MAC. SEA-MAC superiors to RI-MAC in average end-to-end delay by up to 80% and in maximum end-to-end delay up to 90% for all the traffic load in question. SEA-MAC outperforms RI-MAC significantly in average duty cycle under medium and heavy traffic load.

Service-oriented architecture and technologies for automating integration of manufacturing systems and services

Enterprise application integration (EAI) has been pursued strenuously by researchers and industrial practitioners for decades. With the advent of Web Services and Service-Oriented Architecture (SOA), realizing enterprise integration, even automating inter-enterprise interactions become feasible. Virtualization is the fundamental for implementing an SOA based on Web Service technologies. In this paper, we first review the Web Service-Resource Framework (WS-RF) with emphasis on the concepts of Web Services and stateful resource modeling. Then we outline a Service-Oriented architecture that shows how various types of manufacturing resources are virtualized as Web Services; what technologies are used in Web Services register, discovery and transport, and in business process automation. We adopt the WS-Resource approach, for illustration purpose, to virtualize a category of resource-Automatic Guided Vehicle (AGV). Different projections are defined based on WS-Resource properties upon virtualization so as to offer different perspectives to the same resources to meet a variety of business requirements

An energy-efficient MAC protocol with Adaptive Scheduling for wireless sensor networks

Medium access control (MAC) protocols play a crucial role in energy-efficiency, latency reduction for sensor networks. Many research efforts have been made to reduce energy consumption and shorten delay in multi-hop WSNs. Although some existing MAC protocols are energy-efficient and are able to mitigate the end-to-end delivery latency, there are great potential for further improvements. In this paper, we propose a new MAC protocol by introducing a new Adaptive Scheduling (AS) period within which the nodes active duration is made adaptive to variable traffic load and able to resiliently schedule data packets for transmission in the Sleep period. The algorithm is designated to schedule more data packets for transmission in bursty and high traffic loads, thus enabling rapid dissemination of data and reduction of the end-to-end delivery latency. While in the light traffic loads, nodes enters the Sleep mode, mitigating idle listening and saving energy. Experiment results show that the proposed protocol is a great advancement of some existing protocols on performance, especially with heavy traffic loads.

Power-aware service-oriented architecture for wireless sensor networks

Integrating wireless sensor networks (WSNs) into the service-oriented architecture poses many research challenges. One of these challenges is how to apply Web services to the resource constrained WSNs in terms of communication and computation capabilities. Another research challenge is how to build power-aware service-oriented data streaming for WSNs. This paper addresses serviceability issues of WSNs using the Web services resource framework (WSRF) under the open grid service architecture (OGSA). It also addresses the issue of power efficiency for sensor application services that are built on WSRF and provides a query optimization mechanism at Web services level based on the Markov decision process (MDP). We use a work-in-progress project involving condition-based maintenance (CBM) as an industrial application show case.

Proactive health management for automated equipment: from diagnostics to prognostics

In this paper, generic methodologies for prognostic machinery health management are discussed and a framework is proposed for extending prognostic capabilities to conventional maintenance and diagnostic system (MDS). Two specific techniques that can be used to extract knowledge and rules for fault prediction are discussed. These techniques are based on the analysis of historical data gathered by the MDS. The paper further elaborates on knowledge based real-time failure prediction and recommends a diagnostics-to-prognostics approach that enables traditional reactive MDS to be transformed into proactive health management (PHM) systems.

Agent-based service-oriented dynamic resource allocation

Manufacturing shop floor dynamics such as tool breakage or machine breakdown will disrupt the execution of planned production schedules. To deal with such disruptions, a multi-agent system (MAS) based approach has been considered as a means to perform a local rescheduling of affected manufacturing activities by dynamically allocating resources while guided by the objective of minimizing the impact of such disruptions to the planned schedules in order to avoid a global rescheduling. A service-oriented architecture (SOA) was used to allow the negotiation process of dynamic resource allocation to be loosely-coupled between manufacturing resource consumers and manufacturing resource providers.