Exposing the myth: object-relational impedance mismatch is a wicked problem

Addressing a problem of software integration is a fact of life for those involved in software development. The popularity of both object and relational technologies means that they will inevitably be used together. However, the combination of these two technologies introduces problems. These problems are referred to collectively as the object-relational impedance mismatch. A mismatch is addressed using one or more mapping strategies, typically embodied in a pattern. A strategy is concerned with correspondence between the schema of a relational database and an object-oriented program. Such strategies are employed in mapping tools such as Hibernate and TopLink, and reinforce the received wisdom that the problem of object-relational impedance mismatch has been solved. In this paper, we observe that it is not clear whether each strategy, as one possible solution, addresses the cause or a symptom of a mismatch. We argue that the problem is not tame and easily resolved; rather it is complex and wicked. We introduce a catalogue of problem themes that demonstrate the complex nature of the problem and provide a way both to talk about the problem and to understand its complexity. In the future, as software systems become more complex and more connected, it will be important to learn from past endeavours. Our catalogue of problem themes represents a shift, in thinking about the problem of object-relational impedance mismatch, from issues of implementation towards an analysis of cause and effect. Such a shift has implications for those involved in the design of current and future software architectures. Because we have questioned the received wisdom, we are now in a position to work toward an appropriate solution to the problem of object-relational impedance mismatch

System Identification of multi-rotor UAVs using echo state networks

Controller design for aircraft with unusual configurations presents unique challenges, particularly in extracting valid mathematical models of the MRUAVs behaviour. System Identification is a collection of techniques for extracting an accurate mathematical model of a dynamic system from experimental input-output data. This can entail parameter identification only (known as grey-box modelling) or more generally full parameter/structural identification of the nonlinear mapping (known as black-box). In this paper we propose a new method for black-box identification of the non-linear dynamic model of a small MRUAV using Echo State Networks (ESN), a novel approach to train Recurrent Neural Networks (RNN)

Microcomputers as adaptive and protective interfaces in computer networks

Imperial Users onl

Interview

Mark MacLeod interviewed David Ireland at Macquarie University in October 1980

Multi-wavelength holography with a single spatial light modulator for ultracold atom experiments

The authors acknowledge funding from the Leverhulme Trust Research Project Grant RPG-2013-074 and from the EPSRC grant GR/T08272/01.We demonstrate a method to independently and arbitrarily tailor the spatial profile of light of multiple wavelengths and we show possible applications to ultracold atoms experiments. A single spatial light modulator is programmed to create a pattern containing multiple spatially separated structures in the Fourier plane when illuminated with a single wavelength. When the modulator is illuminated with overlapped laser beams of different wavelengths, the position of the structures is wavelength-dependent. Hence, by designing their separations appropriately, a desired overlap of different structures at different wavelengths is obtained. We employ regional phase calculation algorithms and demonstrate several possible experimental scenarios by generating light patterns with 670 nm, 780 nm and 1064 nm laser light which are accurate to the level of a few percent. This technique is easily integrated into cold atom experiments, requiring little optical access.PostprintPeer reviewe

Polarization observables in the longitudinal basis for pseudo-scalar meson photoproduction using a density matrix approach

The complete expression for the intensity in pseudo-scalar meson photoproduction with a polarized beam, target, and recoil baryon is derived using a density matrix approach that offers great economy of notation. A Cartesian basis with spins for all particles quantized along a single direction, the longitudinal beam direction, is used for consistency and clarity in interpretation. A single spin-quantization axis for all particles enables the amplitudes to be written in a manifestly covariant fashion with simple relations to those of the well-known CGLN formalism. Possible sign discrepancies between theoretical amplitude-level expressions and experimentally measurable intensity profiles are dealt with carefully. Our motivation is to provide a coherent framework for coupled-channel partial-wave analysis of several meson photoproduction reactions, incorporating recently published and forthcoming polarization data from Jefferson Lab.Comment: 11 pages, 2 figure

The Potential of Simulation for Teacher Assessment

A teacher’s classroom skills, attitudes, and behaviours are fundamental to excellent teaching. Assessing these qualities is a logistically difficult, costly, and at times, controversial task for teacher educators and school administrators. As a result, teacher hiring and subsequent professional development rely on indirect indicators that provide only limited evidence of a teacher’s potential, strengths, and areas for improvement. Simulation techniques have been used as training and feedback tools for many years in occupations where live practice is dangerous, costly, or difficult to organize. Today’s technologies are making simulations practical in new domains. In teaching they can provide practice settings, performance data, and feedback aimed at evaluating and improving a wide range of skills. Drawing from experience in medical and health education, this chapter outlines the potential for simulations to support both teacher hiring and in-service skills development, in order to support teaching excellence with new tools in the future

SODAS: Surveillance of Drugs of Abuse Study

Objective: Novel Psychoactive Substance (NPS) as a form of recreational drug use has become increasingly popular. There is a paucity of information with regards the prevalence and clinical sequalae of these drugs. The aim of this study was to detect NPS in patients presenting to the Emergency Department (ED) with suspected toxicological ingestion. Methods: The prospective study was performed in a large Emergency Department (ED) in the UK. During a three month period eighty patients were identified by clinicians as having potentially ingested a toxicological agent. Urine sample were analysed using liquid chromatography-high resolution mass spectrometry and basic clinical data was gathered. Results: 80 patients with a history of illicit or recreational drug consumption had urine screenings performed. 49% (39) of patients undergoing a screen had more than one illicit substance detected. 20% (16) of patients tested positive for at least one NPS. Conclusions: Almost half of patients presenting had ingestion of multiple substances which correlated poorly with self reporting of patients. Developing enhanced strategies to monitor evolving drug trends is crucial to the ability of clinicians to deliver care to this challenging group of patients

Feasibility study on microwave stroke detection using a realistic phantom and the FDTD method

This paper presents simulation results of wave propagation in a anatomic realistic head phantom for the purpose of obtaining the feasibility of detecting brain matter affected by a simulated stroke. An elliptical array of transmitter and receiver locations are defined and the differences in the fields created by the presence of the simulated stroke were simulated using a 3-D FDTD method and subsequently quantified

Partnering for the Future: A Case Study in Building Long Term Academic Industry Relationships

A proactive approach to engagement with industry is increasingly forming an integral part of Higher Education Institute (HEI) strategy. At the heart of this engagement focus is the recognition of the need to transition from shorter term transactional relationships to longer term interactive relationships (Jeffrey, 2009) Recognising this need, Technological University Dublin (DIT), one of the largest Higher Education Institutes in Ireland and a pioneer in technological education, sought to create a framework which could foster ongoing dialogue between industry and Institute thereby creating an informed, trusting and supportive environment within which mutually beneficial interaction could be progressed. Accordingly, in 2010, DIT established a Corporate Partnership Network to provide a structure to support the development of academic industry relationships through a better understanding of each other’s environments. By creating an informal yet structured approach, the Network is designed to facilitate the establishment and fostering of long term industry partnerships and to assist industry achieve their organisational objectives in collaboration with DIT. This practitioner case study will document the growth of a relationship between DIT and Bord Gais Networks, a state owned utility company which develops, operates and maintains the natural gas transmission and distribution networks in Ireland. It will highlight the development and role of the DIT’s Corporate Partnership Network in supporting the relationship and its role as a catalyst in generating a variety of interactions including third party accreditation of the company’s training centre, guest presentations, memoranda of understanding, research scholarship sponsorship, and joint programme development. It will also describe organisational approaches at divisional level which support the relationship development