Serious Limitations In Terms Research Articles

Understanding requirements dependency in requirements prioritization: a systematic literature review

Requirement prioritization (RP) is a crucial task in managing requirements as it determines the order of implementation and, thus, the delivery of a software system. Improper RP may cause software project failures due to over budget and schedule as well as a low-quality product. Several factors influence RP. One of which is requirements dependency. Handling inappropriate handling of requirements dependencies can lead to software development failures. If a requirement that serves as a prerequisite for other requirements is given low priority, it affects the overall project completion time. Despite its importance, little is known about requirements dependency in RP, particularly its impacts, types, and techniques. This study, therefore, aims to understand the phenomenon by analyzing the existing literature. It addresses three objectives, namely, to investigate the impacts of requirements dependency on RP, to identify different types of requirements dependency, and to discover the techniques used for requirements dependency problems in RP. To fulfill the objectives, this study adopts the Systematic Literature Review (SLR) method. Applying the SLR protocol, this study selected forty primary articles, which comprise 58% journal papers, 32% conference proceedings, and 10% book sections. The results of data synthesis indicate that requirements dependency has significant impacts on RP, and there are a number of requirements dependency types as well as techniques for addressing requirements dependency problems in RP. This research discovered various techniques employed, including the use of Graphs for RD visualization, Machine Learning for handling large-scale RP, decision making for multi-criteria handling, and optimization techniques utilizing evolutionary algorithms. The study also reveals that the existing techniques have encountered serious limitations in terms of scalability, time consumption, interdependencies of requirements, and limited types of requirement dependencies.

Assisting Glaucoma Screening Process Using Feature Excitation and Information Aggregation Techniques in Retinal Fundus Images

The rapidly increasing trend of retinal diseases needs serious attention, worldwide. Glaucoma is a critical ophthalmic disease that can cause permanent vision impairment. Typically, ophthalmologists diagnose glaucoma using manual assessments which is an error-prone, subjective, and time-consuming approach. Therefore, the development of automated methods is crucial to strengthen and assist the existing diagnostic methods. In fundus imaging, optic cup (OC) and optic disc (OD) segmentation are widely accepted by researchers for glaucoma screening assistance. Many research studies proposed artificial intelligence (AI) based decision support systems for glaucoma diagnosis. However, existing AI-based methods show serious limitations in terms of accuracy and efficiency. Variations in backgrounds, pixel intensity values, and object size make the segmentation challenging. Particularly, OC size is usually very small with unclear boundaries which makes its segmentation even more difficult. To effectively address these problems, a novel feature excitation-based dense segmentation network (FEDS-Net) is developed to provide accurate OD and OC segmentation. FEDS-Net employs feature excitation and information aggregation (IA) mechanisms for enhancing the OC and OD segmentation performance. FEDS-Net also uses rapid feature downsampling and efficient convolutional depth for diverse and efficient learning of the network, respectively. The proposed framework is comprehensively evaluated on three open databases: REFUGE, Drishti-GS, and Rim-One-r3. FEDS-Net achieved outperforming segmentation performance compared with state-of-the-art methods. A small number of required trainable parameters (2.73 million) also confirms the superior computational efficiency of our proposed method.

Language and culture internalization for human-like autotelic AI

Building autonomous agents able to grow open-ended repertoires of skills across their lives is a fundamental goal of artificial intelligence (AI). A promising developmental approach recommends the design of intrinsically motivated agents that learn new skills by generating and pursuing their own goals - autotelic agents. But despite recent progress, existing algorithms still show serious limitations in terms of goal diversity, exploration, generalisation or skill composition. This perspective calls for the immersion of autotelic agents into rich socio-cultural worlds, an immensely important attribute of our environment that shapes human cognition but is mostly omitted in modern AI. Inspired by the seminal work of Vygotsky, we propose Vygotskian autotelic agents - agents able to internalise their interactions with others and turn them into cognitive tools. We focus on language and show how its structure and informational content may support the development of new cognitive functions in artificial agents as it does in humans. We justify the approach by uncovering several examples of new artificial cognitive functions emerging from interactions between language and embodiment in recent works at the intersection of deep reinforcement learning and natural language processing. Looking forward, we highlight future opportunities and challenges for Vygotskian Autotelic AI research, including the use of language models as cultural models supporting artificial cognitive development.

Attitudes and Perceptions of Media Towards Hand Ball Sport in the Case of Ethiopian Handball Premier League

This paper has examined the attitudes and perceptions of sport journalists in covering handball primer league sports that have received very little or no attention in academic studies in Ethiopia. Qualitative cross-sectional design was applied, both available and purposive sampling for data collection. Samples taken for this study were all managers n=10, coaches n= 10, Ethiopian handball federation experts n=7, Sport journals n=7, Total participants N=34, both primary and secondary data sources were used, document analysis secondary data, semi structured interviews and focus group discussion (FGD). Qualitative data were analyzed by the researcher based on research questions. Data was tape recorded and fully transcribed by verbatim. Transcripts were coded, categorized and analyzed using thematic analysis based on the research questions. Quantitative analysis of Descriptive statistics with SPSS version 20 was used for participants’ bio data. According to the semi structured interview results sport journalists tend to write stories, which were exposed to incline on the athletics and football sport, the group response shows that lack of cooperation, continuous pressure and relationship with handball federation and sport’s Medias, handball experts, officials and government made in depth reporting difficult for TV sports journalists. And the document analysis result depicts that even though the hand ball federation has smart national sport policy for handball premier league clubs and projects through the country there is serious limitations in terms of practice and Government and stalk holders have to fulfill adequate and quality sport facilities for EHBP sport clubs expansion.

MECHANICAL DESIGN, ACTUATION AND CONTROL OF BIOINSPIRED SOFT SURGICAL ROBOTS

The design of surgical soft robots is one of the most challenging problems in modern robotics. In addition to the still pending problems of general soft robotics i.e. selection/design of materials, actuators, and mechanical structures, there are serious limitations in terms of their operating environment and conditions: interaction with biological tissues, the effect of sterilization and cleaning liquids, the shape and dimensions of the working space, as well as often occurring accidents during the surgery which poses new robotic control problems to be studied. As it is known, each object of bioinspiration (elephant trunk, octopus leg, etc.) has its own type of motion, kinematic structure, and control, therefore the comparative analysis of soft robots according to different objects of bioinspiration will facilitate their selection and application in minimally invasive surgery (MIS), taking into account, of course, the limitations associated with the surgery. A review of modern literature on mechanical design, methods and technical means of actuation and control of the main types of bioinspired soft surgical robots is presented.The design and development problems, including material selection, mechanical design and optimization, actuation, and bioinspired control for each type of the existing soft surgical robots are discussed. The results and recommendations of this study will help to develop new samples of soft surgical robotic devices with task-specific functional characteristics necessary for MIS applications.

Towards flexible evaluation schemes in areas with lacking information: a case of waste governance in Mexico

Local governments face the need to achieve sustainability in the provision of public services, and to do so, proper governance is essential. This work proposes a method to assess governance in local waste management systems based on a set of indicators that are flexible and robust enough to allow objective and reliable evaluation even where the information that is available is deficient. The proposal is based on a set of indicators divided into six categories that represent an increasing order of governance maturity: institutional framework; government effectiveness; transparency and accountability; network creation; participation; and corruption control. The article presents the proposal and a first test in two Mexican municipalities, which are an example of municipal solid waste management systems in an incipient stage of development, where there may be serious limitations in terms of access to information. The results show that the methodology can be replicated in different contexts and can be useful for making decisions about improvements in municipal solid waste management systems or for comparing them with others. In addition, sufficient information was obtained for a first diagnosis of the cases studied, which indicates the coherence of the proposed framework. Points for practitioners Proper governance is essential to achieve sustainability in the provision of public services. The assessment of local governance must be robust enough to motivate changes and, at the same time, flexible enough to allow reliable evaluation where the quality of service and the availability of information may be scant. We propose a new framework for the assessment of governance in municipal solid waste management systems that meets these requirements, based on a set of indicators clustered according to governance maturity.

Análisis de la cadena productiva del macerado de uva (Vitis labrusca l.) en la región San Martín

La presente investigación surge como respuesta a la presencia de problemas como la poca disponibilidad para establecer asociaciones entre los transformadores de la uva, así como la incapacidad del gobierno local y regional para gestionar programas de desarrollo. El objetivo general formulado fue el determinar los factores de la cadena productiva que están limitando la oferta del producto macerado de uva (Vitis labrusca l.) en la Región San Martín (2018). En cuanto a lo metodológico, se diseñó una investigación no experimental con un nivel exploratorio - descriptivo y correlacional. Se trabajó con una muestra no probabilística de 15 transformadores de macerado de uva. El resultado principal alcanzado fue que: el proceso de abastecimiento desde la óptica del transformador muestra serias limitantes en cuanto a su componente de control de calidad de la materia prima, tanto para la uva y el aguardiente, además, no se viene realizando el análisis fisicoquímico proximal de aguardiente de caña. La conclusión principal muestra un entorno desfavorable para los proveedores de materia prima, debido a la inexistencia de capacidades para garantizar un producto de calidad; no hay presencia de desarrollo tecnológico debido a que la agricultura se desarrolla de manera empírica; del mismo modo no poseen poder de negociación y muestra un bajo aprovechamiento de sus áreas de cultivo y poco acceso a créditos. Además, por la falta de asociatividad, se ven limitados a acceder a programas de apoyo público.

The progress of digitalisation in Mexico: effects on the institutional structure

The purpose of this research is to discuss how industrial and innovation processes in Mexico address the new challenges of the current industrial revolution (Industry 4.0) on production, work practices, public-private collaborative research and the creation of new relational and production capabilities. The work uses data obtained from a questionnaire applied to qualified informants of firms and intermediary organisations in Mexico, looking for their perspectives on the productive incorporation of new digital technologies. The analysed organisations were selected through a theoretical sample (not statistically representative). The analysis carried out takes precautions before the possible bias derived from the selected organisations. Our results show that the perspectives of the actors of the Mexican innovation system, highlights serious limitations in terms of technical and organisational skills of firms to incorporate digital technologies in production processes. The study provides a first exploratory analysis on the visions of the agents involved on the technical and organisational challenges of the new digital technologies. Additionally, this paper provides new analytical inputs to reflect on the potential opportunities of the Mexican firms to adopt these new technical trends and institutional and governance critical aspects for a debate about a national agenda of new industrial and innovation policies.

Risks and opportunities for the progress of digitalization in Mexico

ABSTRACT The aim of this research is to identify Mexico’s current conditions for the incorporation of the changes derived from the processes of increasing digitization into its productive sector, called Industry 4.0. To achieve this goal, this work uses the results obtained from a survey questionnaire answered by qualified technological and productive informants with the purpose of identifying the perspectives of firms initiating this transformation. The selection of information units was based on a theoretical sample (not statistically representative), a methodological feature that forced us to analyze carefully the data collected. The results reached show that, from the perspective of the actors involved, the innovative structure in Mexico presents serious limitations in terms of technical and organizational capabilities of the firms to incorporate digital technologies in their production processes. This paper proposes a first exploratory analysis on the visions of Mexican firms and intermediary organizations that deals with the increasing technical and organizational challenges of the new digital technologies. This article provides analytical and empirical inputs for the analysis of the opportunities that Mexican firms have to incorporate these new technical trends. Finally, the work highlights critical institutional and governance aspects for the debate of national industrial and innovative policy agendas.

The progress of digitalization in Mexico: effects on the institutional structure

The purpose of this research is to discuss how industrial and innovation processes in Mexico address the new challenges of the current industrial revolution (Industry 4.0) on production, work practices, public-private collaborative research and the creation of new relational and production capabilities. The work uses data obtained from a questionnaire applied to qualified informants of firms and intermediary organisations in Mexico, looking for their perspectives on the productive incorporation of new digital technologies. The analysed organisations were selected through a theoretical sample (not statistically representative). The analysis carried out takes precautions before the possible bias derived from the selected organisations. Our results show that the perspectives of the actors of the Mexican innovation system, highlights serious limitations in terms of technical and organisational skills of firms to incorporate digital technologies in production processes. The study provides a first exploratory analysis on the visions of the agents involved on the technical and organisational challenges of the new digital technologies. Additionally, this paper provides new analytical inputs to reflect on the potential opportunities of the Mexican firms to adopt these new technical trends and institutional and governance critical aspects for a debate about a national agenda of new industrial and innovation policies.

Interventions to improve the appropriate use of polypharmacy for older people.

Inappropriate polypharmacy is a particular concern in older people and is associated with negative health outcomes. Choosing the best interventions to improve appropriate polypharmacy is a priority, hence interest in appropriate polypharmacy, where many medicines may be used to achieve better clinical outcomes for patients, is growing. This is the second update of this Cochrane Review. To determine which interventions, alone or in combination, are effective in improving the appropriate use of polypharmacy and reducing medication-related problems in older people. We searched CENTRAL, MEDLINE, Embase, CINAHL and two trials registers up until 7 February 2018, together with handsearching of reference lists to identify additional studies. We included randomised trials, non-randomised trials, controlled before-after studies, and interrupted time series. Eligible studies described interventions affecting prescribing aimed at improving appropriate polypharmacy in people aged 65 years and older, prescribed polypharmacy (four or more medicines), which used a validated tool to assess prescribing appropriateness. These tools can be classified as either implicit tools (judgement-based/based on expert professional judgement) or explicit tools (criterion-based, comprising lists of drugs to be avoided in older people). Two review authors independently reviewed abstracts of eligible studies, extracted data and assessed risk of bias of included studies. We pooled study-specific estimates, and used a random-effects model to yield summary estimates of effect and 95% confidence intervals (CIs). We assessed the overall certainty of evidence for each outcome using the GRADE approach. We identified 32 studies, 20 from this update. Included studies consisted of 18 randomised trials, 10 cluster randomised trials (one of which was a stepped-wedge design), two non-randomised trials and two controlled before-after studies. One intervention consisted of computerised decision support (CDS); and 31 were complex, multi-faceted pharmaceutical-care based approaches (i.e. the responsible provision of medicines to improve patient's outcomes), one of which incorporated a CDS component as part of their multi-faceted intervention. Interventions were provided in a variety of settings. Interventions were delivered by healthcare professionals such as general physicians, pharmacists and geriatricians, and all were conducted in high-income countries. Assessments using the Cochrane 'Risk of bias' tool, found that there was a high and/or unclear risk of bias across a number of domains. Based on the GRADE approach, the overall certainty of evidence for each pooled outcome ranged from low to very low.It is uncertain whether pharmaceutical care improves medication appropriateness (as measured by an implicit tool), mean difference (MD) -4.76, 95% CI -9.20 to -0.33; 5 studies, N = 517; very low-certainty evidence). It is uncertain whether pharmaceutical care reduces the number of potentially inappropriate medications (PIMs), (standardised mean difference (SMD) -0.22, 95% CI -0.38 to -0.05; 7 studies; N = 1832; very low-certainty evidence). It is uncertain whether pharmaceutical care reduces the proportion of patients with one or more PIMs, (risk ratio (RR) 0.79, 95% CI 0.61 to 1.02; 11 studies; N = 3079; very low-certainty evidence). Pharmaceutical care may slightly reduce the number of potential prescribing omissions (PPOs) (SMD -0.81, 95% CI -0.98 to -0.64; 2 studies; N = 569; low-certainty evidence), however it must be noted that this effect estimate is based on only two studies, which had serious limitations in terms of risk bias. Likewise, it is uncertain whether pharmaceutical care reduces the proportion of patients with one or more PPOs (RR 0.40, 95% CI 0.18 to 0.85; 5 studies; N = 1310; very low-certainty evidence). Pharmaceutical care may make little or no difference in hospital admissions (data not pooled; 12 studies; N = 4052; low-certainty evidence). Pharmaceutical care may make little or no difference in quality of life (data not pooled; 12 studies; N = 3211; low-certainty evidence). Medication-related problems were reported in eight studies (N = 10,087) using different terms (e.g. adverse drug reactions, drug-drug interactions). No consistent intervention effect on medication-related problems was noted across studies. It is unclear whether interventions to improve appropriate polypharmacy, such as reviews of patients' prescriptions, resulted in clinically significant improvement; however, they may be slightly beneficial in terms of reducing potential prescribing omissions (PPOs); but this effect estimate is based on only two studies, which had serious limitations in terms of risk bias.

Exploring New Frontiers of Environment Conservation: The Case of Rubber Plantations

The polemics encompassing development and environment conservation during the last two decades have failed to evolve a consensus on appropriate policy interventions in the specific regional,social and ecological contexts. The experience of the prescribed afforestation programmes in the denuded forests and wastelands of the developing counties exhibited serious limitations in terms of economic viability and agronomic sustainability. Among the Eco-friendly alternatives for the afforestation programmes, the case of rubber (Hevea Brasiliensis) plantations merit serious attention based on its reported agronomic sustainability, carbon sequestering effect and ancillary source of income.

Software Requirements Prioritisation: A Systematic Literature Review on Significance, Stakeholders, Techniques and Challenges

As one of the gatekeepers of quality software systems, requirements’ prioritization (RP) is often used to select the most important requirements as perceived by system stakeholders. To date, many RP techniques that adopt various approaches have been proposed in the literature. To identify the strengths, opportunities, and limitations of these existing approaches, this paper studied and analyzed the RP field in terms of its significance in the software development process based on the standard review guidelines by Kitchenham. By a rigorous study selection strategy, 122 relevant studies were selected to address the defined research questions. Findings indicated that RP plays a vital role in ensuring the development of a quality system with defined constraints. The stakeholders involved in RP were reported, and new categories of the participating stakeholders were proposed. Additionally, 108 RP techniques were identified and analyzed with respect to their benefits, prioritization criteria, size of requirements, types in terms of automation level, and their limitations; 84 prioritization criteria were disclosed with their frequency usages in prioritizing the requirements. The study revealed that the existing techniques suffer from serious limitations in terms of scalability, the lack of quantification, and the prioritization of the participating stakeholders, time consumption, requirement interdependences, and the need for highly professional human intervention. These findings are useful for researchers and practitioners in improving the current state of the art and state of practices.

Demographic Convergence and its Linkage with Health Inequalities in India

This thesis comes out at a time when the debate on between-state and social group demographic and health inequalities continues to be largely debated based on most recent available information. However, analyses based on the recent demographic and health data have serious limitations in terms of understanding the true trajectories of between-state and social group inequalities. With the changing demographic scenario and most demographic indicators progressing towards the final stages of transition, the major concern in India has been heterogeneity across region and socioeconomic groups. While the demographic heterogeneity in India is well known, how far the differences are converging or diverging has been a matter of great interest. This study attempted to develop a comprehensive framework to study the demographic transition, convergence and its linkage with health inequalities in India. It advances the empirical examination of demographic convergence assessment by assessing convergence not only in the averages, but also in the absolute and relative inequalities in population and health indicators. The analyses foster that while economic variables are diverging, fertility variables are converging in recent years. Perhaps, it re-affirms the fact that fertility transition is not critically related to economic factors in India. The mortality convergence has some setbacks in recent years. The child health care utilization has shown converging although at a lesser magnitude. Moreover, fertility decline is associated with increasing in child health inequalities in a context where there are pre-existing socioeconomic inequalities. Inequality is often a consequence of progress. Not everyone gets rich at the same time, and not everyone gets immediate access to the latest life-saving measures. Further, growth, inequality, and catch up are the both sides of the same coin. The dark side is what happens when the process is hijacked, so that catch-up never comes. Powerful and wealthy elites have choked off demographic and health progress before, and they can do so again if they are allowed to undermine the institutions on which broad-based demographic and health progress depends. Now, it is confirmed from this study that a mere reduction in the number of children or fertility convergence in averages are not helping in distributing the fruits of demographic progress equally among the children of different states and socioeconomic groups. How far children and their development (particularly in terms of health) are faring during the progress of demographic transition is an important concern for population policy in India.

Using Internet Search Data to Produce State-level Measures: The Case of Tea Party Mobilization

This study proposes using Internet search data from search engines like Google to produce state-level metrics that are useful in social science research. Generally, state-level research relies on demographic statistics, official statistics produced by government agencies, or aggregated survey data. However, each of these data sources has serious limitations in terms of both the availability of the data and its ability to capture important concepts. This study demonstrates how state-level Google search measures can be produced and then demonstrates the effectiveness of such measures in an empirical case: predicting state-level Tea Party movement mobilization. Drawing on existing studies of the Tea Party movement and theories of right-wing and conservative mobilization, state-level Google search measures for anti-immigrant sentiment and economic distress are developed and compared to traditional metrics that are typically used to measure these concepts, such as the unemployment rate and the international immigration rate in their ability to successfully predict Tea Party event counts. The results show that the Google search measures are effective in predicting Tea Party mobilization in a way that is consistent with existing theory, while the traditional measures are not.

New insights in antibody-mediated rejection.

In the present review, we aim to describe the state of knowledge concerning antibody-mediated rejection (ABMR) spectrum and diagnosis criteria before analyzing the present and future promising leads regarding ABMR prognosis markers and treatment. Recent studies regarding complement-binding donor-specific antibodies and the molecular approach highlighted the unmet need for stratification tools for prognosis and treatment inside ABMR disease. ABMR is the leading cause of kidney allograft failure. The recent expansion of its spectrum is related to the paradigm of a continuous process, leading insidiously to a chronic form of ABMR and to the progressive acknowledgement of new entities (such as vascular ABMR, subclinical ABMR, C4d-negative ABMR). Considering the global picture of ABMR, the Banff classification gradually refined the diagnosis criteria so that it now describes a clinically relevant and coherent entity. Nevertheless, if the diagnosis mainly relies on conventional assessment, such as histological findings and circulating donor-specific antibodies, these criteria face serious limitations in terms of stratification of patients at risk of graft loss inside ABMR disease. Recently, new promising tools have emerged in order to identify long-term outcomes at the time of the diagnosis of rejection. In this regard, donor-specific antibodies' complement-fixing ability and the molecular approach contributed significantly. Currently, however, no clinically relevant surrogate marker of treatment efficiency is currently available.

Silver Nanoparticles in Comparison with Ionic Liquid and rGO as Gate Dopant for Paper–Pencil-Based Flexible Field-Effect Transistors

Nanoparticle-based flexible field-effect transistors (FETs) containing carbon nanotubes (CNTs) and silicon nanowires (SiNWs) have attracted tremendous attention, since their interesting device performance can be utilized for integrated nanoscale electronics. However, use of CNTs and SiNWs on polymer substrates poses serious limitations in terms of their fabrication procedure, repeatability, and biodegradability. In this article, we report for the first time the fabrication and characteristics of solution-processed FETs on a paper substrate doped with easily prepared silver nanoparticles (AgNPs). To compare the FET performance, we fabricated two other FETs on paper containing ionic liquid (IL, 1-butyl-3-methylimidazolium octyl sulfate) and reduced graphene oxide (rGO) as dopants. We observe that the AgNP-based dopant generated good FET characteristics in terms of linear transconductance variations and higher carrier concentration values, showing negligible changes after bending and aging. In comparison with the AgNP-FET, the rGO- and IL-based dopants yielded high carrier mobilities, but the rGO-based FET is more susceptible to aging and bending. The excellent linearity of the I DS–V G curve found for the AgNP-FET ensures its applicability for devices requiring linear transfer characteristics such as linear amplifiers.

A curvature optimal sharp corner smoothing algorithm for high-speed feed motion generation of NC systems along linear tool paths

Conventional tool paths for computer numerical-controlled (CNC) machine tools or NC positioning systems are mainly composed of linear motion segments, or the so-called G1 commands. This approach exhibits serious limitations in terms of achieving the desired part of geometry and productivity in high-speed machining. Velocity and acceleration discontinuities occur at the junction points of consecutive segments. In order to generate smooth and continuous feed motion, a geometric corner smoothing algorithm is proposed in this paper, which fits quintic B-splines to blend adjacent straight lines together. The proposed transition scheme ensures G 2 continuity transitions and optimal curvature geometry delivering fast cycle time without violating the axis acceleration limits. The cornering error is controlled analytically allowing the user to set the desired cornering tolerance. The feed profile along the corner-blended tool path is generated based on S-curve-type acceleration profile, and it is scheduled for minimum cycle time. At last, the corner-blended tool path is interpolated in real-time with minimum feed fluctuation for accurate and smooth feed motion. Proposed algorithms are implemented, and their effectiveness is tested on a CNC machine tool.

Durability assessment of natural stone

Durability is one of the most significant aspects of the behaviours of natural stone in the real environment. As it is not a fundamental property, it cannot be measured in situ or by using any simple laboratory test. Therefore, durability is assessed by using several approaches such as (1) accelerated laboratory durability tests (freeze–thaw cycling, wetting–drying, salt crystallization resistance), (2) complex environmental testing in test cabinets, and (3) exposure site testing. In this review paper, the advantages and drawbacks of these approaches are discussed and compared with other approaches such as practical experience and/or indirect assessments of selected physical properties, which have been found empirically to have a strong influence upon the durability of materials. Based on current information, accelerated laboratory durability tests (although the most widespread type of tests) exhibit serious limitations in terms of oversimplified test methods. Complex environmental testing provides more reliable results, but is less accessible for common testing owing to experiments’ long duration and high operational costs. Similar drawbacks are applicable for in situ testing. Practical experience combines the value of the material’s exposure in real-life conditions and the duration of interactions; but it is highly impractical when the sampling of experimental materials is required. Extrapolation of the durability of natural stone from the results of some common laboratory tests (porosimetry approach for complex evaluation of pore space; mechanical properties under various degrees of saturation; response of a natural stone exposed to water (i.e. swelling behaviour)) seems to be an appropriate alternative to previous approaches.

A Performance and Usability Aware Secure Two-Factor User Authentication Scheme for Wireless Sensor Networks

Recently, several user authentication schemes for wireless sensor networks based on two-factor concept using the smart card technology were proposed. However, they have serious limitations in terms of security and usability. First, even though they are enhancements of other works, they still have several security flaws, such as vulnerability against parallel session, privileged-insider, and gateway-node bypassing attacks and lack of mutual authentication between user station and gateway node. On the other hand, they also present a usability constraint, in a sense that they do not consider the use case when sensor nodes cannot communicate with gateway node. In this case, data collected by isolated sensor nodes could not be accessed until they recover such communication, which is in many times not recoverable rapidly or forever (e.g., military applications, natural disaster monitoring). Due to all these reasons, this paper proposes a robust user authentication scheme which fixes the security weaknesses of previous solutions and provides wider usability considering the use case when the sensor nodes cannot communicate with the gateway node. Once the solution is described, its security is ensured by formal proof and analysis against attacks. Additionally, performance and cost analysis are executed to determine its level of feasibility for real implementation.