Network protection codes: Providing self-healing in autonomic networks using network coding

Agile recovery from link failures in autonomic communication networks is essential to increase robustness, accessibility, and reliability of data transmission. However, this must be done with the least amount of protection resources, while using simple management plane functionalities. Recently, network coding has been proposed as a solution to provide agile and cost efficient self-healing against link failures, in a manner that does not require data rerouting, packet retransmission, or failure localization, hence leading to simple control and management planes. To achieve this, separate paths have to be provisioned to carry encoded packets, hence requiring either the addition of extra links, or reserving some of the resources for this purpose.In this paper we introduce self-healing strategies for autonomic networks in order to protect against link failures. The strategies are based on network coding and reduced capacity, which is a technique that we call network protection codes (NPC). In these strategies, an autonomic network is able to provide self-healing from various network failures affecting network operation. Also, network protection codes are extended to provide self-healing from multiple link failures in autonomic networks. Although this leads to reducing the network capacity, the network capacity reduction is asymptotically small in most cases of practical interest. We provide implementation aspects of the proposed strategies, derive bounds and show how to construct network protection code. The paper also develops an Integer Linear Program formulation to evaluate the cost of provisioning connections using the proposed strategies, and uses results from this formulation to show that it is more resource efficient than 1 + 1 protection. A simulation study to evaluate the recovery times, and the buffering requirements due to network coding is also conducted using the OPNET simulator.     

RAID0.5: design and implementation of a low cost disk array data protection method

RAID has long been established as an effective way to provide highly reliable as well as high-performance disk subsystems. However, reliability in RAID systems comes at the cost of extra disks. In this paper, we describe a mechanism that we have termed RAID0.5 that enables striped disks with very high data reliability but low disk cost. We take advantage of the fact that most disk systems use offline backup systems for disaster recovery. With the use of these offline backup systems, the disk system needs to only replicate data since the last backup, thus drastically reducing the storage space requirement. Though RAID0.5 has the same data loss characteristics of traditional mirroring, the lower storage space comes at the cost of lower availability. Thus, RAID0.5 is a tradeoff between lower disk cost and lower availability while still preserving very high data reliability. We present analytical reliability models and experimental results that demonstrate the enhanced reliability and performance of the proposed RAID0.5 system.     

Moving the suspended load of an overhead crane along a pre-specified path: A non-time based approach

This paper introduces a noncolocated non-time based regulator for the path tracking control of the suspended load of a four degrees of freedom gantry crane. The regulator is named Delayed Reference Noncolocated Control (DRNC). The DRNC control action is exerted by modifying the moving platform reference trajectory. Such a goal is achieved by both shifting trajectory execution in time, and modifying the platform path with respect to the reference path defined for the load. Simulation results prove the capability of the method to ensure extremely precise path tracking, while ensuring very simple controller implementation, which makes it well suited for industrial application.     

A hybrid methodology for restructuring decision of a manufacturing system: A case study

The output performance of a manufacturing system depends on its operational continuity. However, a manufacturing system can stop for a short time or it can be out of service for a long time due to crucial problems such as poor performance of old machines, unexpected breakdowns or faulty plant and system design. Many firms try to restructure their manufacturing systems to avoid these crucial problems and to be more efficient, profitable and better organized. However, the decision to begin the process of restructuring is a difficult and critical choice for most decision makers due to the fact that the decision threshold of the process is ambiguous. This paper proposes a hybrid methodology for the decision makers who will decide on restructuring a manufacturing system. The proposed methodology provides crucial information for the decision makers combining fuzzy logic approach and reliability analysis.     

Factors affecting adoption of smart meters in the post-Fukushima era in Taiwan: an extended protection motivation theory perspective

This study aims to understand factors influencing the intention to adopt smart meters (SM) to save energy in the face of expected increases in electricity costs, stemming from the impact of Taiwan’s plans to increase the proportion of renewable energy in the post-Fukushima era demand. As far as we know, compared to previous relevant studies based on constructs of perceived usefulness, perceived ease of use, and attitudes, this study is the first one based on the application of protection motivation theory (PMT), which uses threat appraisal, coping appraisal, Social Influence, Secondary Data Influence constructs, and control variables to explain the correlation and impact of residential communities’ intention to adopt SM. With 292 valid questionnaires, this study applies SmartPLS 3 software in model analysis, and finds that the impact of coping appraisal variables is more significant than that of threat appraisal variables, while Secondary Data Influence, Age, and Electricity Cost variables have a significant influence on the intention to adopt SM. The relevant results and practical contributions are discussed.     

The design and analysis of unequal error protection fountain coding for multiple source networks over binary erasure channels

A novel network model of multiple source fountain coding is developed and a novel class of generic multiple source fountain codes with unequal error protection(UEP)property is proposed.The And–Or tree analysis technique is generalized to analyze the asymptotic performance of the proposed codes and a joint optimization method employing both linear and nonlinear programs is developed to optimize the degree distributions.Furthermore,we propose three basic methods to achieve UEP property and the performance of each method is discussed.We employ these analytical results and optimization method to design and discuss several UEP codes with two and four sources for different application scenarios.Simulation results verify that the proposed codes can be applied to the networks with any number of sources and can provide strong UEP property in various ways based on the proposed three basic methods.     

Reliability of MEMS: A perspective on failure mechanisms,improvement solutions and best practices at development level

Reliability of MEMS (MicroElectroMechanical-Systems) devices is a crucial aspect as it can discriminate the successful from partially or totally missed reaching of Microsystem technology based market products. However, the topic of MEMS reliability is significantly articulated, as it comprises numerous physics of failure and diverse failure mechanisms. Thereafter, it requires a pronounced sensitivity related to the actual operation conditions (environmental and functional) of the Microsystem device within the final application. In other words, reliability of MEMS is nowadays regarded as a standalone transversal discipline that must be seriously taken into account already from the early design phase. The purpose of this paper is to provide the reader at first with basic knowledge around the concept of reliability. Thereafter, the most relevant physics of failure and failure mechanisms typical of MEMS are grouped and briefly discussed, with specific attention to their employment in the field of displays. A synthetic review of valuable solutions to improve specific reliability aspects of MEMS devices for diverse applications is then proposed to the reader. Eventually, a brief discussion focused on best practices to address properly reliability during the whole development chain of innovative MEMS based products completes the contribution. It is a belief of the author that the particular blend of topics and aspects reported in the following pages, as well as the attitude of considering reliability as a transversal discipline of science, contribute to provide this contribution with an important benefit if compared to the reviews on reliability of MEMS previously published in literature.     

Understanding the effect of knowledge management strategies on knowledge management performance: A contingency perspective

The universalistic perspective research on employing a unidimensional knowledge management (KM) strategy has yielded conflicting findings and recommendations in different contexts. This study proposes a contingency model for investigating the effects of KM strategies on KM performance to resolve these contradictions. Drawing on the knowledge-based view (KBV) of the firm, which identifies knowledge type and origin as two key KM dimensions, this study first defines four KM strategies: external codification, internal codification, external personalization, and internal personalization. A multiple contingency model of KM strategy is then developed based on a technology–organization–environment framework. This study proposes that the effectiveness of each KM strategy depends on both external and internal contextual conditions, namely, environmental knowledge intensity and organizational information systems (IS) maturity. To test and validate the contingency model, we analyze data from 141 firms to explain the effects of KM strategies on KM performance. Our results reveal three KM strategies, not including the internal personalization strategy, which have a significant association with KM performance in their hypothesized contexts. This study expands KM strategy research by theoretically developing an advanced contingency model aligned with external and internal contexts and by providing valuable practical suggestions to managers for selecting a KM strategy based on multiple contingencies related to the external and internal conditions of a firm.     

Assessing the use of hearing protection in industrial settings: A comparison between methods

In industrial environments, hearing protection devices (HPDs) are used to protect workers from noise exposure. However, the effectiveness of this practice can be compromised when workers periodically remove their HPDs while exposed to noise, which greatly affects the attenuation of the devices. Therefore, it is important for techniques that assess the “real” use of HPDs to be accurate. This study analysed the accuracy and reliability of three HPD assessment methods: (1) the self-reported use, (2) the use of a statistical sampling observation method and (3) the use of video to monitor (record) all of the workers' activity. The studied techniques were applied in an industrial environment where 2 types of HPDs are used and where wearing HPDs is compulsory. The results demonstrated that self-reported data differ from the observed workers' behaviour and that workers tend to overestimate their use of the HPDs. From the analysed variables, it can be concluded that the self-reported data are more reliable for older workers and for those with greater experience in using HPDs. Accordingly, it can be concluded that the self-reported use of HPDs is a good, practical method, particularly in terms of the time-effectiveness, cost and accuracy of the technique.     

Proteomics: A new perspective for the understanding of pterygia

Pterygia is a common ocular surface disease bothering both the patient because of its unsightly appearance and the surgeon because of its tendency to recur. The pathogenesis of pterygia is complex and the exact mechanism(s), especially at the molecular level, remains unknown. The use of modern proteomic techniques such as iTRAQ may yield new knowledge on the underlying pathogenesis of pterygia. In this issue of Proteomics Clinical Applications, Linghu et al. (article number 1600094) identified a total of 156 proteins that expressed differently between the pterygia and healthy conjunctiva using the isobaric tags for relative and absolute quantification based quantitative proteomic analysis. Most significantly, western blotting confirmed that two candidate proteins matrix metalloproteinase 10 (MMP‐10) and CD34 were significantly upregulated in pterygia, suggesting that they have potential roles in the pathogenesis of pterygia. The findings in Linhu's study may provide a new perspective for the understanding of pterygia and develop a new therapeutic target.     

Analysis of facility protection strategies against an uncertain number of attacks: The stochastic R-interdiction median problem with fortification

We present the Stochastic R-Interdiction Median Problem with Fortification (S-RIMF). This model optimally allocates defensive resources among facilities to minimize the worst-case impact of an intentional disruption. Since the extent of terrorist attacks and malicious actions is uncertain, the problem deals with a random number of possible losses. A max-covering type formulation for the S-RIMF is developed. Since the problem size grows very rapidly with the problem inputs, we propose pre-processing techniques based on the computation of valid lower and upper bounds to expedite the solution of instances of realistic size. We also present heuristic approaches based on heuristic concentration-type rules. The heuristics are able to find an optimal solution for almost all the problem instances considered. Extensive computational testing shows that both the optimal algorithm and the heuristics are very successful at solving the problem. Finally, a discussion of the importance of recognizing the stochastic nature of the number of possible attacks is provided.     

A review of path following control strategies for autonomous robotic vehicles: Theory,simulations, and experiments

This article presents an in-depth review of path following control strategies that are applicable to a wide range class of marine, ground, and aerial autonomous robotic vehicles. From a control system standpoint, path following can be formulated as the problem of stabilizing a path following error system that describes the dynamics of position and possibly orientation errors of a vehicle with respect to a path, with the errors defined in an appropriate reference frame. In spite of the large variety of path following methods described in the literature we show that, in principle, most of them can be categorized in two groups: stabilization of the path following error system expressed either in the vehicle's body frame or in a frame attached to a “reference point” moving along the path, such as a Frenet-Serret (F-S) frame or a Parallel Transport (P-T) frame. With this observation, we provide a unified formulation that is simple but general enough to cover many methods available in the literature. We then discuss the advantages and disadvantages of each method, comparing them from the design and implementation standpoint. We further show experimental results of the path following methods obtained from field trials testing with under-actuated and over-actuated autonomous marine vehicles. In addition, we introduce open-source Matlab and Gazebo/ROS simulation toolboxes that are helpful in testing path following methods before their integration in the combined guidance, navigation, and control systems of autonomous vehicles.     

Cooperative strategies of wireless access technologies: A game-theoretic analysis

The wireless Internet has to overcome the problem of spectrum scarcity as the number of mobile equipments could increase even by an order of magnitude in the next decade; the cooperation of mobile devices is foreseeable as a feasible solution to the problems. There exists a large body of literature on opportunistic ad hoc networking including Pelusi et al. (2006) [25], Chen et al. (2006) [26], Hui et al. (2005) [27]; however, the impact of the location of the devices on their access method selection is not yet appropriately dealt with. In this paper, we address this issue based on game-theoretic analyses. The key contribution of our work is threefold. First, we model the access method selection of mobile devices by extending the classical forwarding game with position, mobility, and availability of the devices. Second, we apply the model in game-theoretic analyses to better understand the optimal cooperation strategies in the presence of heterogeneous wireless technologies. We further extend our framework to include uncertainty. Finally, we present the applicability of the model in a cognitive radio scenario where complex structures of parameters are included.     

Analysis of the return on preventive measures in musculoskeletal disorders through the benefit–cost ratio: A case study in a hospital

Work-related musculoskeletal disorders (WMSDs) are among the most costly health problems that society is facing today. Prevention involves investments and it is important for organizations to make a cost–benefit analysis of ergonomic projects. Return on prevention is a recent concern in the domain of occupational safety and health (OSH). There are many studies concerning the return on the prevention of WMSDs, in terms of the benefits for the organization in which the preventive measures are implemented. However, it is also important to perform an analysis of the impact of each measure on society (externalities). A model to perform a financial and economic cost–benefit analysis related to OSH projects was developed and it was applied in the case of the prevention of WMSDs in a Portuguese hospital. An analysis of the accidents and corresponding costs has been made in six of the services of the hospital. Financial and an economic cost–benefit analysis have been made and the benefit–cost ratio (B/C) has been calculated. While the B/C financial ratio, considering only the benefits to the hospital, is around 2, the economic B/C ratio, taking into account all the external benefits that have been quantified, is higher than 14.Relevance to industryBoth the economic and the financial B/C ratio are important support tools for decision makers in public and private organizations, helping them to define which preventive measures should be implemented, taking into account the costs involved and the resulting quantified benefits, for the organization, for the workers and for the society.     

An exploration of a quasi-stable online network: A longitudinal perspective

This study uses social capital theory and social network analysis to explore how relations in an online academic communication network impact the overall structure of that network. Social network analysis is a particularly advantageous methodological tool for linking changes in microlevel choices to macrolevel structural alterations. Results indicate the online communication network’s structure exists independent of changes in communication ties. Specifically degree centrality, betweenness centrality, and clique formation indicated communication ties are initiated and discontinued over a 7-month timeframe. However, the dynamic nature of the microlevel communication choices does not mirror the quasi-stable structure of the online network. Results provide avenues for future research.     

Data aggregation in constructing composite indicators: A perspective of information loss

Composite indicators (CIs) have been widely accepted as a useful tool for performance comparisons, public communication and decision support in a wide spectrum of fields, e.g. economy, environment and knowledge/information/innovation. The quality and reliability of a CI depend heavily on the underlying construction scheme where data aggregation is a major step. This paper analyzes the data aggregation problem in CI construction from the point of view of information loss. Based on the “minimum information loss” principle, the distance-based and entropy-based aggregation models for constructing CIs are presented. The entropy-based aggregation model has also been extended to deal with qualitative data. It is shown that the proposed aggregation models have close relationships with several popular MCDA aggregation methods in CI construction, although our proposed models seem to be more flexible while more complex in application. Two case studies are presented to illustrate the use of the proposed aggregation models.     

Finding the Latent Semantics of Haptic Interaction Research: A Systematic Literature Review of Haptic Interaction Using Content Analysis and Network Analysis

As interest in multimodal and tangible interfaces is increasing in the field of human–robot interaction and virtual reality, haptics has been researched across areas such as engineering, computer science, psychology, and neuroscience. The main objective of the study was to construct a comprehensive review of the current haptic‐related literature based on quantitative data derived from content analysis and network analysis. Using the results of content analysis and network analysis of 6,000 research articles on haptic interaction, the haptic‐related literature was classified into two categories: 1) studies on technologies providing haptic stimuli and 2) studies on the human perception of haptic stimuli. Emotions in haptic feedback and haptic perception characteristics of various body sites were identified as potential research topics for further investigation. Greater research effort on understanding human haptic sensation and perception using the proposed systematic approach could accelerate the development of haptic interaction technology.     

Fault tree analysis: A survey of the state-of-the-art in modeling,analysis and tools

Fault tree analysis (FTA) is a very prominent method to analyze the risks related to safety and economically critical assets, like power plants, airplanes, data centers and web shops. FTA methods comprise of a wide variety of modeling and analysis techniques, supported by a wide range of software tools. This paper surveys over 150 papers on fault tree analysis, providing an in-depth overview of the state-of-the-art in FTA. Concretely, we review standard fault trees, as well as extensions such as dynamic FT, repairable FT, and extended FT. For these models, we review both qualitative analysis methods, like cut sets and common cause failures, and quantitative techniques, including a wide variety of stochastic methods to compute failure probabilities. Numerous examples illustrate the various approaches, and tables present a quick overview of results.     

Investigating patterns of interaction in networked learning and computer-supported collaborative learning: A role for Social Network Analysis

The focus of this study is to explore the advances that Social Network Analysis (SNA) can bring, in combination with other methods, when studying Networked Learning/Computer-Supported Collaborative Learning (NL/CSCL). We present a general overview of how SNA is applied in NL/CSCL research; we then go on to illustrate how this research method can be integrated with existing studies on NL/CSCL, using an example from our own data, as a way to synthesize and extend our understanding of teaching and learning processes in NLCs. The example study reports empirical work using content analysis (CA), critical event recall (CER) and social network analysis (SNA). The aim is to use these methods to study the nature of the interaction patterns within a networked learning community (NLC), and the way its members share and construct knowledge. The paper also examines some of the current findings of SNA analysis work elsewhere in the literature, and discusses future prospects for SNA. This paper is part of a continuing international study that is investigating NL/CSCL among a community of learners engaged in a master’s program in e-learning.