Integrity determination of RTK solutions in precision farming applications

Integrity of Real Time Kinematic (RTK) positioning solutions relates to the confidential level that can be placed in the information provided by the RTK system. It includes the ability of the RTK system to provide timely valid warnings to users when the system must not be used for the intended operation. For instance, in the controlled traffic farming (CTF) system that controls traffic separates wheel beds and root beds, RTK positioning error causes overlap and increases the amount of soil compaction. The RTK system’s integrity capacity can inform users when the actual positional errors of the RTK solutions have exceeded Horizontal Protection Levels (HPL) within a certain Time-To-Alert (TTA) at a given Integrity Risk (IR). The later is defined as the probability that the system claims its normal operational status while actually being in an abnormal status, e.g., the ambiguities being incorrectly fixed and positional errors having exceeded the HPL. The paper studies the required positioning performance (RPP) of GPS positioning system for PA applications such as a CTF system, according to literature review and survey conducted among a number of farming companies. The HPL and IR are derived from these RPP parameters. A RTK-specific rover autonomous integrity monitoring (RAIM) algorithm is developed to determine the system integrity according to real time outputs, such as residual square sum (RSS), HDOP values. A two-station baseline data set is analyzed to demonstrate the concept of RTK integrity and assess the RTK solution continuity, missed detection probability and false alarm probability.

A practical example of a siphon at work

In this paper, some classroom experiments are described for correcting the common misconception that the operation of a siphon depends on atmospheric pressure. One experiment makes use of a chain model of a siphon and another demonstrates that flow rate is dependent on the height difference between the inflow and outflow of a siphon and not atmospheric pressure. A real-life example of the use of a siphon to refill a lake in South Australia is described, demonstrating that the siphon is not only of academic interest but has practical applications.

Motivation and perception factors influence buying home behaviour in Dilly, East Timor

Demand of low cost housing increased from 1995 to 1997 which is shown by the number of housing loan approval. In order to develop the most suitable marketing plan, developer needs to know some factors which influenced to the decision making process of buying house. This research used a residential development in PT Delta Comoro Permai, Dilly as a case study. A survey to homeowners has been done to evaluate the motivation and perception factors in buying home behaviour. The survey has been done on the 3rd August to 29th August 1998. In this study, four main components have been examined. Physical and linkage are not as important as environment and utilities for the homebuyer. Moreover, the result is consistent with developer’s motto ‘clean, secure, aesthetic, healthy and prosperity’. This study provides further recommendation in the environment and utilities components for the new development in the future.

Does Chinese traditional values matter in regulating China's company directors? Preliminary findings from surveys in Hong Kong

Much has been said about Chinese corporate governance and the new laws on companies. While most literature focuses on either the political or the legal doctrinal issues, this paper argues that Chinese traditional values do matter in Chinese corporate governance. The object of this paper is to report on the preliminary findings of a project supported by the General Research Fund in Hong Kong (HK). Thus far the survey results from HK respondents support our hypothesis. As such, traditional Chinese values should be on the agenda of the next round of company law reforms in China.

Surviving the Titanic disaster : economic, natural and social determinants

The sinking of the Titanic in April 1912 took the lives of 68 percent of the people aboard. Who survived? It was women and children who had a higher probability of being saved, not men. Likewise, people traveling in first class had a better chance of survival than those in second and third class. British passengers were more likely to perish than members of other nations. This extreme event represents a rare case of a well-documented life and death situation where social norms were enforced. This paper shows that economic analysis can account for human behavior in such situations.

Performance pressure an empirical analysis using world and Euro cups data

There is a notable shortage of empirical research directed at measuring the magnitude and direction of stress effects on performance in a controlled environment. One reason for this is the inherent difficulties in identifying and isolating direct performance measures for individuals. Additionally most traditional work environments contain a multitude of exogenous factors impacting individual performance, but controlling for all such factors is generally unfeasible (omitted variable bias). Moreover, instead of asking individuals about their self-reported stress levels we observe workers' behavior in situations that can be classified as stressful. For this reason we have stepped outside the traditional workplace in an attempt to gain greater controllability of these factors using the sports environment as our experimental space. We empirically investigate the relationship between stress and performance, in an extreme pressure situation (football penalty kicks) in a winner take all sporting environment (FIFA World Cup and UEFA European Cup competitions). Specifically, we examine all the penalty shootouts between 1976 and 2008 covering in total 16 events. The results indicate that extreme stressors can have a positive or negative impact on Individuals' performance. On the other hand, more commonly experienced stressors do not affect professionals' performances.

The role of trust in inter-project knowledge transfer

Knowledge is a powerful organisational asset yet intangible and hard to manage, particularly in a project environment where there is a tendency to repeat the same mistakes rather than learn from previous project lessons. A lack of effective knowledge sharing across projects causes reinventions that are costly, and time consuming. Research on knowledge transfer has focused mainly on functional organisations and only recent attention has been directed towards knowledge transfer in projects. Furthermore, there is little evidence in the literature which examines trust in the knowledge transfer processes. This paper studies how the three types of trust - ability, benevolence, and integrity impact on knowledge transfer from the inter-project perspective. Three case studies investigated the matter. A detailed description of the work undertaken and an analysis of interviews with project professionals from large project-based organisations are presented in this paper. The key finding identifies the positive impact of ability trust on knowledge transfer. However, it was also found that perception on both integrity and benevolence varied across organisations suggesting that there can be a possible impact of organisational factors on the way trust is perceived in inter-project knowledge transfer. The paper concludes with a discussion and recommendations regarding the development of trust for inter-project environment.

System identification and control of an aerobot drive system

Fast thrust changes are important for authoritive control of VTOL micro air vehicles. Fixed-pitch rotors that alter thrust by varying rotor speed require high-bandwidth control systems to provide adequate performace. We develop a feedback compensator for a brushless hobby motor driving a custom rotor suitable for UAVs. The system plant is identified using step excitation experiments. The aerodynamic operating conditions of these rotors are unusual and so experiments are performed to characterise expected load disturbances. The plant and load models lead to a proportional controller design capable of significantly decreasing rise-time and propagation of disturbances, subject to bus voltage constraints.

The intention to notice : the collection, the tour and ordinary landscapes

The Intention to Notice: the collection, the tour and ordinary landscapes is concerned with how ordinary landscapes and places are enabled and conserved through making itineraries that are framed around the ephemera encountered by chance, and the practices that make possible the endurance of these material traces. Through observing and then examining the material and temporal aspects of a variety of sites/places, the museum and the expanded garden are identified as spaces where the expression of contemporary political, ecological and social attitudes to cultural landscapes can be realised through a curatorial approach to design, to effect minimal intervention. Three notions are proposed to encourage investigation into contemporary cultural landscapes: To traverse slowly to allow space for speculations framed by the topographies and artefacts encountered; to [re]make/[re]write cultural landscapes as discursive landscapes that provoke the intention to notice; and to reveal and conserve the fabric of everyday places. A series of walking, recording and making projects undertaken across a variety of cultural landscapes in remote South Australia, Melbourne, Sydney, London, Los Angeles, Chandigarh, Padova and Istanbul, investigate how communities of practice are facilitated through the invitation to notice and intervene in ordinary landscapes, informed by the theory and practice of postproduction and the reticent auteur. This community of practice approach draws upon chance encounters and it seeks to encourage creative investigation into places. The Intention to Notice is a practice of facilitating that also leads to recording traces and events; large and small, material and immaterial, that encourages both conjecture and archive. Most importantly, there is an open-ended invitation to commit and exchange through design interaction.