Rigorous Environment Research Articles

Fermat Point Based Joint Routing in Dual-Aggregation-Points Inter-Backup M2M Communications

Machine-to-machine (M2M) communications can be widely used in military probing, disasters monitoring, etc., where have rigorous environment and require reliable communications. In order to provide enough reliability, M2M subnet can be deployed with two inter-backup aggregation points. This paper proposed a novel routing algorithm named Fermat Point based Joint Routing (FPJR) for such dual-aggregation-points inter-backup M2M Communications. Taking nodes on Fermat Points as route anchors, FPJR forms joint routes which can decrease energy cost and improve communication efficiency greatly. Further, considering the probability is quite little that there is exactly a node deployed on an appointed Fermat Point, we proposed a new terminology ‘ -Fermat Region’, which denotes the circle area with the Fermat Point as center and as radius. Based on -Fermat Region and through the FPJR interaction protocol, FPJR can act not only separately but also as the aid of other routing algorithms, without any compatibility problem. The simulation results show that FPJR can greatly decrease packet lost ratio, energy cost and packet delay.

Carbon fixation by biological soil crusts following revegetation of sand dunes in arid desert regions of China: A four-year field study

Abstract Biological soil crusts (BSCs) are important sources of carbon input to ecosystems in arid and semiarid regions, where vascular plants are restricted by the rigorous environment and limited soil water. Sand dune stabilization by revegetation can enhance colonization and development of BSCs on sandy soil surfaces, and convert BSCs from the early successional stage dominated by cyanobacteria and algae to the later stage dominated by lichens and mosses. This study estimated the carbon fixation by two successional stages of BSCs based on four years of field observations. Carbon fixation by two BSCs has been compared via estimating daily carbon fixation using measuring net photosynthesis with ten sampling plots per crust stage in situ, combining with calculating the wet daytime of crustal cryptogam thallus. However, diurnal carbon fixation of both BSCs was largely determined by crustal water content rather than photosynthesis photon flux and temperature. The range of optimal gravimetric water content for early BSCs was 1–3.5%, and 1–5% for the later BSCs. The annual carbon fixation was 11.36 g C m − 2 yr − 1 for cyanobacteria–algae dominated crusts and 26.75 g C m − 2 yr − 1 for lichen–moss dominated crusts. The latter had a higher carbon input due to a higher water-holding capacity, prolonging wet daytime and higher chlorophyll content, as well as higher light capture. These findings indicate the recovery of BSCs is expected to significantly increase carbon input into sandy desert ecosystems.

Enhancing pose accuracy of space robot by improved differential evolution

Due to the intense vibration during launching and rigorous orbital temperature environment, the kinematic parameters of space robot may be largely deviated from their nominal parameters. The disparity will cause the real pose (including position and orientation) of the end effector not to match the desired one, and further hinder the space robot from performing the scheduled mission. To improve pose accuracy of space robot, a new self-calibration method using the distance measurement provided by a laser-ranger fixed on the end-effector is proposed. A distance-measurement model of the space robot is built according to the distance from the starting point of the laser beam to the intersection point at the declining plane. Based on the model, the cost function about the pose error is derived. The kinematic calibration is transferred to a non-linear system optimization problem, which is solved by the improved differential evolution (DE) algorithm. A six-degree of freedom (6-DOF) robot is used as a practical simulation example, and the simulation results show: 1) A significant improvement of pose accuracy of space robot can be obtained by distance measurement only; 2) Search efficiency is increased by improved DE; 3) More calibration configurations may make calibration results better.

Multiple testing in statistical analysis of systems-based information retrieval experiments

High-quality reusable test collections and formal statistical hypothesis testing together support a rigorous experimental environment for information retrieval research. But as Armstrong et al. [2009b] recently argued, global analysis of experiments suggests that there has actually been little real improvement in ad hoc retrieval effectiveness over time. We investigate this phenomenon in the context of simultaneous testing of many hypotheses using a fixed set of data. We argue that the most common approaches to significance testing ignore a great deal of information about the world. Taking into account even a fairly small amount of this information can lead to very different conclusions about systems than those that have appeared in published literature. We demonstrate how to model a set of IR experiments for analysis both mathematically and practically, and show that doing so can cause p -values from statistical hypothesis tests to increase by orders of magnitude. This has major consequences on the interpretation of experimental results using reusable test collections: it is very difficult to conclude that anything is significant once we have modeled many of the sources of randomness in experimental design and analysis.

Characteristics of Channels of IEEE 802.15.4 Compliant Sensor Networks

Wireless sensor networks have been more and more deployed for monitoring and controlling real environments. However, because of sensor nodes’ limitations, their radios are more susceptible to noise and interference than in other wireless technologies. These are critical factors in the rigorous industrial environment, whose effects may not be the same on all channels of a sensor network. In this paper, we present some experimental studies about the characteristics of IEEE 802.15.4 channels in ISM band. We are particularly interested in the differences of implementing wireless sensor networks in academic and industrial environments. A common problem of wireless sensor network implementations is that most of them are purely academic or initially prepared in laboratory. Our study shows that it is very difficult to predict the quality and stability of the different channels in sensor networks, as the environment conditions greatly influence the network performance. Empirical approaches are suitable methods for choosing the appropriate channels to deploy WSNs in noisy environments. We conduct several tests in both laboratory and in a real world environment, particularly in an oil refinery as this is our case study in the context of the FP7 GINSENG project (Ginseng 2010).

Stable Routing Algorithm for Mobile Ad Hoc Network

Mobile Ad Hoc network is a multi-hop temporary autonomous system of mobile nodes with wireless transmitters and receivers without the aid of pre-established network infrastructure. With a great deal of different applications increasing, it needs to provide stable communication for such network. In this paper, a new routing algorithm is proposed which can dynamically estimate delay variety and calculate link stability factor. In the route discovery phase, it finds paths meeting delay requirement with greatest stable link. In the route maintenance phase, it effectively keeps monitoring network topology changes through delay prediction and performs rerouting in time. Furthermore, some enhancement strategies are adopted to control route acquisition latency and improve transmission quality. Simulation results show that it can meet with the delay requirement while decrease the routing cost. Comparing with other conventional routing algorithms, it can achieve higher packet delivery rate especially in rigorous network environment.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing sub-Saharan African (SSA) economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two Research Workshops every year. Their purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a one-day plenary session is devoted to address topical policy-relevant issues. During each session, state-of-the-art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening the existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might be effectively addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state of the art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.

A Pedagogy of Justice

Within the deeply subjective space of post-secondary classrooms where art is both subject and praxis, canon and methodology frequently converge to reproduce asymmetrical systems of power. The disruption of these systems is arduous and rewarding work, work that requires a committed consortium of students, teachers and extended community. My teaching practice is a pedagogy of justice that uses divergent source material to challenge participants to interrogate the historical, political, and cultural components of their frameworks of analysis and those at play in the material at hand. Within the intellectually rigorous learning environment that my pedagogy of justice requires, I aim to teach students to enrich their thinking and communicative skills through critical self-reflexivity. This is risky business. It asks students and teachers to look closely at their moorings and at times to untie systems of meaning-making that have held together their worldviews for a long time.

Research and Classification of Inflatable Space Vehicle and its Materials

Inflatable space vehicle (ISV) has a variety of advantages of light mass, volume changeability and low cost, and becomes the hotspot in space vehicle research recently. But most researchers concentrate their efforts on applications of ISV in their dedicated domains, and the holistic viewpoint of ISV is indistinct. In this paper, the new developing space vehicle, ISV is classified into flatness, lenticula, sphere and cabin in brief due to its different structures and applications. Each type owns its special materials for folding, inflation-deployment, rigidization and resistibility in the space rigorous environment. Materials utilized in typical ISV are summarized subsequently, which can be sorted by polymer films, flexible rigidizable composites and multiple-layer laminates. Finally, the properties of ISV materials including environment endurance, mechanics, fabrication technologies and special functions are concluded, which is useful in material design and optimization.

Does Lower Crab Creek in the Eastern Washington Desert Have a Native Population of Chinook Salmon?

AbstractLower Crab Creek (LCC) in eastern Washington is a groundwater‐fed tributary to the Columbia River at river kilometer 661. The creek traverses agriculturally modified desert habitat, and in several reaches the water quality is poor, summer water temperatures are lethal to fish, and stream habitat is degraded. The creek was thought to be unsuitable for salmonids, yet fall‐run Chinook salmon Oncorhynchus tshawytscha spawn and rear in it. The origin of these fish is uncertain since it is unclear whether LCC was a perennial creek prior to the hydrologic changes in the Columbia River basin stemming from the Columbia Basin Irrigation Project in the 1950s. We used genetic analyses to examine the hypotheses that these fish are (1) random strays, (2) a population founded since the 1950s (by wild or hatchery strays), or (3) an established native population. Chinook salmon juveniles and adults were collected in LCC and genetically characterized with the Chinook salmon microsatellite DNA locus suite in the Genetic Analysis of Pacific Salmonids database. The LCC population of Chinook salmon was found to be significantly different from interior Columbia River basin hatchery and wild populations and to have alleles that are absent from proximal populations. Lower Crab Creek Chinook salmon showed no evidence of recent founding and had genetic diversity, allelic richness, and effective population size similar to those of other Columbia River basin Chinook salmon. The data suggest that a genetically distinct, native population of Chinook salmon inhabits LCC that has adapted to the rigorous environment.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing Sub-Saharan African economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two Research Workshops every year. Its purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a one-day plenary session is devoted to addressing topical policy-relevant issues. During each session, state-of-the-art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might be effectively addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state-of-the-art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing Sub-Saharan African economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two Research Workshops every year. Their purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a one-day plenary session is devoted to addressing topical policy-relevant issues. During each session, state-of-the-art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might be effectively addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state-of-the-art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.

On the Origin of Tibetans and Their Genetic Basis in Adapting High-Altitude Environments

Since their arrival in the Tibetan Plateau during the Neolithic Age, Tibetans have been well-adapted to extreme environmental conditions and possess genetic variation that reflect their living environment and migratory history. To investigate the origin of Tibetans and the genetic basis of adaptation in a rigorous environment, we genotyped 30 Tibetan individuals with more than one million SNP markers. Our findings suggested that Tibetans, together with the Yi people, were descendants of Tibeto-Burmans who diverged from ancient settlers of East Asia. The valleys of the Hengduan Mountain range may be a major migration route. We also identified a set of positively-selected genes that belong to functional classes of the embryonic, female gonad, and blood vessel developments, as well as response to hypoxia. Most of these genes were highly correlated with population-specific and beneficial phenotypes, such as high infant survival rate and the absence of chronic mountain sickness.

Retrospective Investigation of an Influenza A/H1N1pdm Outbreak in an Italian Military Ship Cruising in the Mediterranean Sea, May-September 2009

BackgroundClinical surveillance may have underestimated the real extent of the spread of the new strain of influenza A/H1N1, which surfaced in April 2009 originating the first influenza pandemic of the 21st century. Here we report a serological investigation on an influenza A/H1N1pdm outbreak in an Italian military ship while cruising in the Mediterranean Sea (May 24-September 6, 2009).MethodsThe contemporary presence of HAI and CF antibodies was used to retrospectively estimate the extent of influenza A/H1N1pdm spread across the crew members (median age: 29 years).FindingsDuring the cruise, 2 crew members fulfilled the surveillance case definition for influenza, but only one was laboratory confirmed by influenza A/H1N1pdm-specific RT-PCR; 52 reported acute respiratory illness (ARI) episodes, and 183 reported no ARI episodes. Overall, among the 211 crew member for whom a valid serological result was available, 39.3% tested seropositive for influenza A/H1N1pdm. The proportion of seropositives was significantly associated with more crowded living quarters and tended to be higher in those aged <40 and in those reporting ARI or suspected/confirmed influenza A/H1N1pdm compared to the asymptomatic individuals. No association was found with previous seasonal influenza vaccination.ConclusionsThese findings underline the risk for rapid spread of novel strains of influenza A in confined environment, such as military ships, where crowding, rigorous working environment, physiologic stress occur. The high proportion of asymptomatic infections in this ship-borne outbreak supports the concept that serological surveillance in such semi-closed communities is essential to appreciate the real extent of influenza A/H1N1pdm spread and can constitute, since the early stage of a pandemic, an useful model to predict the public health impact of pandemic influenza and to establish proportionate and effective countermeasures.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing sub-Saharan African economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two research workshops every year. Their purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a 1-day plenary session is devoted to addressing topical policy-relevant issues. During each session, state-of-the-art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening the existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might be effectively addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state of the art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.

Fracture Cause Analysis and Improvement on Waveguide Tube of Satellite Calibration Antenna in Random Vibration

Satellite calibration antenna suffered rigorous vibration environment in the course of lunching. Random vibration is being specified for acceptance tests by spacecraft structure. The waveguide tube of antenna was cracked in the random vibration test. Fracture analysis using scanning electron microscopic showed that failure were induced by fatigue damage. Finite element model of antenna was built and root mean square (rms) stress of waveguide tube was obtained in random vibration analysis. The maximum rms stress was 35.6MPa and located at the flange base. Then fatigue life of waveguide tube was estimated, using the Palgren-Miner rule and the three-band method. The estimated fatigue life of 109 seconds showed the waveguide tube couldn’t ensure safety during 120 seconds of the random vibration. Finally two ribs were added at each flange base for decreasing the stress concentration. The fatigue life of improved waveguide tube was 811 seconds. Then it passed the random vibration test.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing sub-Saharan African (SSA) economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two research workshops every year. Their purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a one-day plenary session is devoted to addressing topical policy-relevant issues. During each session, state-of-the-art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening the existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might effectively be addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state of the art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.

Performance of TC4 Titanium Alloys Coated with Different Sol

Titanium alloys has been widely used in many fields, while in high temperature and rigorous corrosive environment, it is very necessary to do some work on the surface of titanium alloys to satisfy with application purpose. In this paper, four kinds of sol film were prepared on titanium alloys with and without anodic oxidation film. The prepared sol included Al2O3, Al2O3-ZrO2 and doped sol by adding additive into them respectively. The film thickness, high temperature oxidation resistance and corrosion resistance after high temperature oxidation for some time were investigated. The results show that the sol film obtained on the anodic oxidation film of titanium alloys is thicker than that without anodic oxidation film. Compared with the other three kinds of film, the doped Al2O3-ZrO2 sol film has the best high temperature oxidation resistance and corrosion resistance due to insulation effect of the sol film, and the composition of additive and zirconic.

Ideological Dissonance: A Comparison of the Views of Eight Conservative Students with the Recruitment Document from a Southeastern College of Education

The experiences of conservative students in universities have garnered increased attention in recent years. This paper presents the results of recent research on the campus of a large Southeastern university. Situated in a small Southeastern college town, the university in question is home to a College of Education that attempts to maintain the spirit and tradition of progressive education. However, the College also serves a population that includes many conservative communities and individuals. This research is the result of a focus group interview with eight self-defined conservative students at the College of Education and an analysis of official recruitment and orientation documents. The investigation’s findings support the need to clarify the recruitment procedures and curriculum of the institution in order to assist conservative students entering a progressive institution, while at the same time, challenging all students, including those with conservative views, to take part in a rigorous intellectual environment.

Preface

In furtherance of its mission of strengthening local capacity for conducting independent rigorous inquiry into problems of managing Sub-Saharan African economies and facilitating evidence-based policy-making in the region, the African Economic Research Consortium (AERC) holds two Research Workshops every year. Their purpose is to offer a rigorous environment for African economists to present their research and receive constructive criticisms voiced by their peers and resource persons from within and outside the region. At the commencement of each research workshop, a one-day plenary session is devoted to addressing topical policy relevant issues. During each session, state of the art papers are presented on the chosen topic by leading economists worldwide. Topics addressed in the previous plenary sessions included: The primary objectives of the plenary sessions are to (i) inform AERC researchers on emerging issues in a particular area of research, (ii) provide a forum for signalling new research concerns or deepening existing ones within the thematic focus and (iii) provide lessons to policy-makers on how such issues might be effectively addressed in the African context. Authors of plenary papers are, therefore, leading experts on the relevant topic whose presentations typically cover the state of the art with respect to issues, methodology and evidence from Africa and elsewhere as well highlight potential areas for further research.