A Survey of Access Control Models in Wireless Sensor Networks

Copyright 2014 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/3.0/)Wireless sensor networks (WSNs) have attracted considerable interest in the research community, because of their wide range of applications. However, due to the distributed nature of WSNs and their deployment in remote areas, these networks are vulnerable to numerous security threats that can adversely affect their proper functioning. Resource constraints in sensor nodes mean that security mechanisms with a large overhead of computation and communication are impractical to use in WSNs; security in sensor networks is, therefore, a challenge. Access control is a critical security service that offers the appropriate access privileges to legitimate users and prevents illegitimate users from unauthorized access. However, access control has not received much attention in the context of WSNs. This paper provides an overview of security threats and attacks, outlines the security requirements and presents a state-of-the-art survey on access control models, including a comparison and evaluation based on their characteristics in WSNs. Potential challenging issues for access control schemes in WSNs are also discussed.Peer reviewe

Inertia and Change in the Early Years: Employment Relations in Young, High Technology Firms

[Excerpt] This paper considers processes of organizational imprinting in a sample of 100 young, high technology companies. It examines the effects of a pair of initial conditions: the founders\u27 models of the employment relation and their business strategies. Our analyses indicate that these two features were well aligned when the firms were founded. However, the alignment has deteriorated over time, due to changes in the distribution of employment models. In particular, the \u27star\u27 model and \u27commitment\u27 model are less stable than the \u27engineering\u27 model and the \u27factory\u27 model. Despite their instability, these two blueprints for the employment relation have strong effects in shaping the early evolution of these firms. In particular, firms that embark with these models have significantly higher rates of replacing the founder chief executive with a non-founder as well as higher rates of completing an initial public stock offering. Some implications of these findings for future studies of imprinting and inertia in organizations are discussed

Engineering Bureaucracy: The Genesis of Formal Policies, Positions, and Structures in High-Technology Firms

[Excerpt] This article examines the impact of organizational founding conditions on several facets of bureaucratization—managerial intensity, the proliferation of specialized managerial and administrative roles, and formalization of employment relations. Analyzing information on a sample of technology start-ups in California\u27s Silicon Valley, we characterize the organizational models or blueprints espoused by founders in creating new enterprises. We find that those models and the social composition of the labor force at the time of founding had enduring effects on growth in managerial intensity (i.e., reliance on managerial and administrative specialists) over time. Our analyses thus provide compelling evidence of path dependence in the evolution of bureaucracy—even in a context in which firms face intense selection pressures—and underscore the importance of the logics of organizing that founders bring to new enterprises. We find less evidence that founding models exert persistent effects on the formalization of employment relations or on the proliferation of specialized senior management titles. Rather, consistent with neo-institutional perspectives on organizations, those superficial facets of bureaucracy appear to be shaped by the need to satisfy external gatekeepers (venture capitalists and the constituents of public corporations), as well as by exigencies of organizational scale, growth, and aging. We discuss some implications of these results for efforts to understand the varieties, determinants, and consequences of bureaucracy

Mobile Network Defense Interface for Cyber Defense and Situational Awareness

Today\u27s computer networks are under constant attack. In order to deal with this constant threat, network administrators rely on intrusion detection and prevention services (IDS) (IPS). Most IDS and IPS implement static rule sets to automatically alert administrators and resolve intrusions. Network administrators face a difficult challenge, identifying attacks against a vast number of benign network transactions. Also after a threat is identified making even the smallest policy change to the security software potentially has far-reaching and unanticipated consequences. Finally, because the administrator is primarily responding to alerts they may lose situational awareness of the network. During this research a MNDI was created that visualized a live network under cyber attack. MNDI allowed test subjects to take actions and make configuration changes in real time on the network. The interface was designed to take advantage of state-of-the-art touch technology engaging the network administrator in the defense of the network. MNDI increased administrator\u27s ability to make time-sensitive decision quickly and accurately on their network. MNDI was tested against a set of open source network administration tool implemented on a desktop system. Both systems used an automated system that polled an ES to resolve zero to 75% of the alerts. The amount of alerts resolved is referred to as level of automation (LOA). During the experiment MNDI outperformed the desktop configuration at all LOAs. The test results showed a statistical difference between the percentage of alerts correctly resolved and the time between actions on MNDI versus desktop test subjects

An evaluation of break-the-glass access control model for medical data in wireless sensor networks

Wireless Sensor Networks (WSNs) have recently attracted a lot of attention in the research community because it is easy to deploy them in the physical environment and collect and disseminate environmental data from them. The collected data from sensor nodes can vary based on what kind of application is used for WSNs. Data confidentiality and access control to that collected data are the most challenging issues in WSNs because the users are able to access data from the different location via ad-hoc manner. Access control is one of the critical requirements to prevent unauthorised access from users. The current access control models in information systems cannot be applied straightforwardly because of some limitations namely limited energy, resource and memory, and low computation capability. Based on the requirements of WSNs, we proposed the Break-The-Glass Access Control (BTG-AC) model which is the modified and redesigned version of Break-The-Glass Role-Based Access Control (BTG-RBAC) model. The several changes within the access control engine are made in BTG-RBAC to apply and fit in WSNs. We developed the BTG-AC model in Ponder2 package. Also a medical scenario was developed to evaluate the BTG-AC model for medical data in WSNs. In this paper, detail design, implementation phase, evaluation result and policies evaluation for the BTG-AC model are presented. Based on the evaluation result, the BTG-AC model can be used in WSNs after several modifications have been made under Ponder2 Package

Determinants of Managerial Intensity in the Early Years of Organizations

This paper examines how founding conditions shape subsequent organizational evolution— specifically, the proliferation of management and administrative jobs. Analyzing quantitative and qualitative information on a sample of young technology start-ups in California’s Silicon Valley, we examine the enduring imprint of two aspects of firms’ founding conditions: the employment blueprints espoused by founders in creating new enterprises; and the social capital that existed among key early members of the firm—their social composition and social relations. We find that the initial gender mix in start-ups and the blueprint espoused by the founder influence the extent of managerial intensity that develops over time. In particular, firms whose founders espoused a bureaucratic model from the outset subsequently grew more administratively intense than otherwise-similar companies, particularly companies whose founders had initially championed a “commitment” model. Also, firms with a higher representation of women within the first year subsequently were slower to bureaucratize than otherwise-similar firms with a predominance of males. Our analyses thus provide compelling evidence of path-dependence in the evolution of organizational structures and underscore the importance of the “logics of organizing” that founders bring to new enterprises. Implications of these results for organizational theory and research are discussed

Species - Dependent Cardiac And Motor Responses To Cholinergic Stimulation In Daphnia Pulex And Daphnia Magna

The role of acetylcholine (ACh) in regulating the activity of the heart and `feeding current\u27 driven by the beating thoracic appendages of Daphnia pulex and Daphnia magna was evaluated using acetylcholinesterase inhibitors (AChE-I) and muscarinic receptor agonists. Single animals, tethered to a stainless steel pin, were tested in a watertight aquatic chamber that allowed free movement of appendages and swimming antennae. Heart contraction rate and the rate of thoracic appendage beating were quantified optically by measuring fluctuating changes in light-intensity caused by movement. Physostigmine, neostigmine, oxotremorine, pilocarpine as well as nicotine were used to study ACh and AChE. Atropine was used to attempt to block responses caused by the drugs used. The findings strongly support the role of ACh in the regulation of appendage beat rate, and suggest that AChE inhibition results in sufficiently high ACh levels to affect the rate of rhythmic appendage beating

Inhibition of Pol I Transcription a New Chance in the Fight Against Cancer

While new cancer treatments continue to improve patient outcomes, for some cancers there have been limited or no improvements for a long time. It is for these cases radically new approaches are required. Recent publications proposing ribosome biogenesis, in particular RNA polymerase I transcription, as a suitable target for cancer treatment has been gaining momentum. For example, we demonstrated that CX-5461, a specific RNA polymerase I transcription inhibitor, is effective in treating an aggressive subtype of acute myeloid leukemia, regardless of p53 status. Notably, CX-5461 reduces the leukemia initiating/stem cells, the cell population believed to be responsible for chemotherapy resistance and disease relapse in numerous cancers. Targeting ribosome biogenesis, once considered merely a “housekeeping process,” is showing promise in a continuously growing list of cancers including lymphoma, prostate, and now acute myeloid leukemia. Evidence suggests the therapeutic efficacy of RNA polymerase I therapy in preclinical models is mediated through a variety of mechanisms including nucleolar stress activation of p53, DNA damage-like activation of ataxia-telangiectasia mutated/ataxia-telangiectasia and Rad3 related, and cellular differentiation. Overall, the available data suggests the potential for targeting ribosome biogenesis to be effective in a broad spectrum of cancers. The outcomes of 2 phase 1/2 trials of CX-5461 in hematological malignancies and breast cancer are eagerly awaited.This work was supported by project grants from the National Health and Medical Research Council program grant (#1053792), and the Cancer Council of Victoria grant-in-aid (#1084545)

Impact of wearable physical activity monitoring devices with exercise prescription or advice in the maintenance phase of cardiac rehabilitation: systematic review and meta-analysis

BackgroundPhysical activity (PA) is a component of cardiac rehabilitation (CR). However, life-long engagement in PA is required to maintain benefits gained. Wearable PA monitoring devices (WPAM) are thought to increase PA. There appear to be no reviews which investigate the effect of WPAM in cardiac populations. We firstly aimed to systematically review randomised controlled trials within the cardiac population that investigated the effect WPAM had through the maintenance phase of CR. We specifically examined the effect on cardiorespiratory fitness (CRF), amount and intensity of daily PA, and sedentary time. Secondly, we aimed to collate outcome measures reported, reasons for drop out, adverse events, and psychological impact from utilising a WPAM.MethodsA systematic search (up to January 2019) of relevant databases was completed, followed by a narrative synthesis, meta-analysis and qualitative analysis.ResultsNine studies involving 1,352 participants were included. CRF was improved to a greater extent in participants using WPAM with exercise prescription or advice compared with controls (MD 1.65mL/kg/min;95% confidence interval [CI; 0.64-2.66]; p=0.001; I-2=0%). There was no significant between group difference in six-minute walk test distance. In 70% of studies, step count was greater in participants using a WPAM with exercise prescription or advice, however the overall effect was not significant (SMD 0.45;95% [CI; -0.17-1.07] p=0.15; I-2=81%). A sensitivity analysis resulted in significantly greater step counts in participants using a WPAM with exercise prescription or advice and reduced the heterogeneity from 81 to 0% (SMD 0.78;95% [CI;0.54-1.02];