Developing a stand density module in LANDIS to improve simulation realism of stand dynamics

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Title from PDF of title page (University of Missouri--Columbia, viewed on November 18, 2009).Thesis advisor: Dr. Hong S. He.M.S. University of Missouri--Columbia 2009.Long-term landscape modeling is dependent on various forest dynamics including large-scale disturbances, environmental effects, land management and stand-scale succession. The stand density module was designed for LANDIS to link stand-level processes with large-scale landscape phenomena. The stand density module design is built based on the simple models of ecosystem processes which are suitable for large-scale landscape modeling. The stand density module is invented as a module that requires minimal parameterization and can be calibrated with empirical stand data. The stand density module predicted the basal area very accurately based on comparisons with the field data in spite of the simple model framework. The stand density module can interact with other modules in LANDIS reciprocally, thus the combined results allowed us to analyze the effects of various management regimes, inter- and intra-specific competition and interactions between disturbances on stand-level ecological processes. Finally, the stand density module in LANDIS provides valuable feedbacks between stand dynamics and large-scale ecological processes.Includes bibliographical references

Human centred design of software agent in social network service against privacy concerns

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThe rapid growth and influence of social network services has led many scholars to focus on privacy issues. However, the research described in this thesis was motivated by the small number of design studies that have focused on practical approaches to identifying tacit information from users’ instant non-verbal responses to privacy issues. The research therefore aimed to propose persona models as a design solution for software agent development based on the analysis of users’ emotional and behavioural responses, so as to address privacy issues in social network services. In the definition phase, 21 stakeholders belonging to three key stakeholder groups were recruited for unstandardised semistructured email interviews. Three main considerations for the design of software agents in social network services emerged from the interviews, which were classified into the following categories: comprehensive understanding of users’ perceptions of privacy; user type recognition algorithm for software agent development; and existing software agent enhancement. In the development phase, 50 participants were recruited for the Facebook case study, which included three research strategies: perceptions of privacy questionnaire for user typology; emotional response measurement using Geneva Emotion Wheel; and behavioural response observation using a contextual inquiry method. The participants were classified into four user types by means of cluster analysis: uninformed, trustful, suspicious and neglectful. Each user type’s key emotional responses were identified using Kruskal-Wallis test and Mann-Whitney U test, and key behavioural responses using affinity diagrams. This generated persona models of each user type that reflected the correlations between users’ perceptions of privacy, key emotional responses and key behavioural responses. Two fundamental features of the software agent were also proposed based on the persona models: confirmation and guidance. In the validation phase, software agent prototypes were created based on the proposed persona models. A total of 206 participants completed the online survey which included two sections: perceptions of privacy questionnaire for user typology replication, and key emotional responses measurement before and after the intervention of the software agent prototypes. Cluster analysis replication validated the proposed user typology, and Wilcoxon signed-rank test of key emotional responses validated the proposed persona models. By implementing the research outcomes, the software agent described in this thesis would be able to provide users with appropriate services based on their user types, to reduce the number of those who are still unaware of privacy practice and those who neglect their accounts, and to expand the size of a user group pursuing sound relationships

Micro Sensor Node for Air Pollutant Monitoring: Hardware and Software Issues

Wireless sensor networks equipped with various gas sensors have been actively used for air quality monitoring. Previous studies have typically explored system issues that include middleware or networking performance, but most research has barely considered the details of the hardware and software of the sensor node itself. In this paper, we focus on the design and implementation of a sensor board for air pollutant monitoring applications. Several hardware and software issues are discussed to explore the possibilities of a practical WSN-based air pollution monitoring system. Through extensive experiments and evaluation, we have determined the various characteristics of the gas sensors and their practical implications for air pollutant monitoring systems

Differences in Korean learners acquisition of causative expressions: focus on learners proficiency level

This study examines the learning patterns of intermediate and advanced Korean learners in the acquisition of causative expressions according to their proficiency and the causative sentence type. We measured their grammatical knowledge using three types of grammaticality judgment tasks (GJTs) and self-paced reading tasks (SPRTs) differing in time limit and modality. We included the GJT A' score and reading time (RT) for SPRTs target and spillover regions. The results showed that intermediate learners accuracy for morphological and lexical causatives was lower than that for syntactic causatives, while advanced learners accuracy for lexical causatives was lower than that for syntactic and morphological causatives. Learners showed a lower accuracy for timed written and aural GJTs than untimed GJT. In SPRT, learners took twice as long to process the target regions as native speakers and even longer to process spillover regions. Advanced learners had a longer RT. Learners had a low correct rate for causative suffix substitution and adjectival root questions, substitution questions on causative markers, and substitution questions on causee case postpositions in morphological, syntactic, and lexical causatives. Learners showed confusion with active sentences in lexical causatives. This study has implications for understanding causative expression acquisition for learners proficiency levels

Optimality Conditions in Nondifferentiable G-Invex Multiobjective Programming

We consider a class of nondifferentiable multiobjective programs with inequality and equality constraints in which each component of the objective function contains a term involving the support function of a compact convex set. We introduce G-Karush-Kuhn-Tucker conditions and G-Fritz John conditions for our nondifferentiable multiobjective programs. By using suitable G-invex functions, we establish G-Karush-Kuhn-Tucker necessary and sufficient optimality conditions, and G-Fritz John necessary and sufficient optimality conditions of our nondifferentiable multiobjective programs. Our optimality conditions generalize and improve the results in Antczak (2009) to the nondifferentiable case

Y-MAC: An Energy-Efficient Multi-channel MAC Protocol for Dense Wireless Sensor Networks

As the use of wireless sensor networks (WSNs) becomes widespread, node density tends to increase. This poses a new challenge for Medium Access Control (MAC) protocol design. Although traditional MAC protocols achieve low-power operation, they use only a single channel which limits their performance. Several multi-channel MAC protocols for WSNs have been recently proposed. One of the key observations is that these protocols are less energy efficient than single-channel MAC protocols under light traffic conditions. In this paper, we propose an energy efficient multi-channel MAC protocol, Y-MAC, for WSNs. Our goal is to achieve both high performance and energy efficiency under diverse traffic conditions. In contrast to most of previous multi-channel MAC protocols for WSNs, we implemented Y-MAC on a real sensor node platform and conducted extensive experiments to evaluate its performance. Experimental results show that Y-MAC is energy efficient and maintains high performance under high-traffic conditions

Purdue Autonomous Aerial Vehicle (AAV) Vertically Integrated Project Abstract

Our goal in building this drone is to create a drone-based on open source software and components, that has an ability to do various autonomous tasks. There is an increasing number of applications that drones are being used for. With facial recognition, drones can be used for security purposes and many other important applications. For our drone specifically, a Pixhawk controller is used for flight control and stability. The Pixhawk controls the attitude and also enables the drone to follow pre-mapped routes. A wireless telemetry system is used to get first-person view video from the drone, and to display flight information. The drone is flown primarily using the remote control but can also be operated from the mission planner application on a PC. In order to do image processing and object recognition, a Raspberry Pi controller is attached to the drone and serves as a slave computer that communicates to the Pixhawk via MavProxy. The Raspberry Pi runs an algorithm that identifies an object through the camera and tracks this object by keeping the object within a specified pixel range. To keep the drone positioned over the object, the Raspberry Pi sends commands to the Pixhawk controller through a serial port. The Raspberry Pi will be running an OpenCV library in order to access the necessary software. This technology is becoming very prevalent in our society today in both the private and public sectors. Bringing autonomous abilities to this quadcopter opens up limitless possibilities for the interaction of human and machine and allows further exploration into this realm of technology

Algal plankton turn to hunting to survive and recover from end-Cretaceous impact darkness

The end-Cretaceous bolide impact triggered the devastation of marine ecosystems. However, the specific kill mechanism(s) are still debated, and how primary production subsequently recovered remains elusive. We used marine plankton microfossils and eco-evolutionary modeling to determine strategies for survival and recovery, finding that widespread phagotrophy (prey ingestion) was fundamental to plankton surviving the impact and also for the subsequent reestablishment of primary production. Ecological selectivity points to extreme postimpact light inhibition as the principal kill mechanism, with the marine food chain temporarily reset to a bacteria-dominated state. Subsequently, in a sunlit ocean inhabited by only rare survivor grazers but abundant small prey, it was mixotrophic nutrition (autotrophy and heterotrophy) and increasing cell sizes that enabled the eventual reestablishment of marine food webs some 2 million years later.</p

Virmid: accurate detection of somatic mutations with sample impurity inference

Detection of somatic variation using sequence from disease-control matched data sets is a critical first step. In many cases including cancer, however, it is hard to isolate pure disease tissue, and the impurity hinders accurate mutation analysis by disrupting overall allele frequencies. Here, we propose a new method, Virmid, that explicitly determines the level of impurity in the sample, and uses it for improved detection of somatic variation. Extensive tests on simulated and real sequencing data from breast cancer and hemimegalencephaly demonstrate the power of our model. A software implementation of our method is available at http://sourceforge.net/projects/virmid/