Output-feedback binary adaptive control of MIMO systems using monitoring function

The problem of adaptive control design for multivariable linear time-invariant plants with unknown control direction is considered. A solution is proposed based on the SDU factorization of the high frequency gain matrix (HFG) and the monitoring function approach. The adaptation scheme is the binary model reference adaptive control (BMRAC) which utilizes parameter projection and sufficiently high adaptation gains. The signs of the leading principal minors of the HFG define the control directions, and the lack of knowledge of which is a major challenge in the multivariable framework. The role of the monitoring function is to monitor the output error transient and then provide the necessary changes of the adaptation gain signs to guarantee a stable adaptive control. In addition to proving the signal boundedness of the resulting closed-loop system, the output tracking error is shown to be asymptotically as well as exponentially practically stable, i.e., exponentially stable with respect to a small residual compact set of size inversely proportional to the BMRAC adaptation gain. The latter implies good transient properties of the output tracking error in contrast to conventional adaptive laws which only guarantee asymptotic stability but can lead to extremely slow error convergence. The extension of the proposed approach to matched disturbances is also briefly discussed following the classical paradigm of disturbance estimators. Numerical results with a visual servoing application illustrate the efficiency of the proposed method.     

Bridging the gap between policy and practice: adopting a strategic vision for partnership working in special education

The desirability of parents and professionals in special education working in partnership continues to be expressed through Government policy and legislation and through voluntary sector initiatives. Moreover, partnership working attracts significant financial investment. Yet effective, working parent - professional partnerships often remain elusive in practice. In this article, Susanna Pinkus, a teacher, consultant and teaching practice supervisor who recently completed her PhD, describes her research into partnerships between parents and professionals. She bases her assertions on the daily experiences of 14 parents based in four London education authorities and attributes an absence of effective collaboration to lack of understanding about how partnerships between parents and professionals do, and should, function in the special educational context. In order to bridge this gap between the rhetoric of policy and the difficulties that are frequently reported in developing parent-professional relationships in practice, Susanna Pinkus identifies and discusses four principles as being central to forming effective partnerships.     

Material characterization and preservation guidance for a collection of prosthetic limbs developed since 1960

National Museums Scotland has collections relating to many areas of science and technology, including medical science. This paper considers technical and conservation issues of an important collection of more than 150 prosthetic limbs. Much of the collection is of prosthetics developed for children born lacking or with malformed upper limbs caused by the prenatal morning sickness drug Thalidomide. However, many other examples are represented and the collection showcases a timeline of bioengineering development covering the past five decades. A wide range of plastics and metals were observed within the pieces examined, with many visibly degraded and degrading. The identification and characterization of these materials and their condition are fundamental to interpreting the development of the collection, for deciding on treatment, and for setting a strategy for future preservation. In addition to visual inspection, three analytical techniques were used to examine the various parts of the selected examples: Fourier transform infrared spectroscopy for polymer identification and condition; X-ray fluorescence spectroscopy to identify the metals and alloys present, and X-radiography to reveal the internal mechanisms of the limbs. Interpretation of the results was greatly enhanced by documentation and conversation with engineers and scientists involved in research and development of the limbs. The combination of different materials, some with conflicting environmental requirements, makes storage and display challenging as the goal is to prevent degradation of any part the object. Some objects were found to be actively degrading and for these separate storage solutions have been recommended to slow the emission of volatile degradation products that would cause further damage throughout the collection.     

Elongated unique DNA strand deposition on microstructured substrate by receding meniscus assembly and capillary force

Ordered deposition of elongated DNA molecules was achieved by the forced dewetting of a DNA solution droplet over a microstructured substrate. This technique allows trapping, uncoiling, and deposition of DNA fragments without the need of a physicochemical anchoring of the molecule and results in the combing of double stranded DNA from the edge of microwells on a polydimethylsiloxane (PDMS) substrate. The technique involves scanning a droplet of DNA solution caught between a movable blade and a PDMS substrate containing an array of microwells. The deposition and elongation appears when the receding meniscus dewets microwells, the latter acting here as a perturbation in the dewetting line forcing the water film to break locally. Thus, DNA molecules can be deposited in an ordered manner and elongated conformation based solely on a physical phenomenon, allowing uncoiled DNA molecules to be observed in all their length. However, the exact mechanism that governs the deposition of DNA strands is not well understood. This paper is an analysis of the physical phenomenon occurring in the deposition process and is based on observations made with the use of high frame/second rate video microscopy.     

Global real-time optimization by output-feedback extremum-seeking control with sliding modes

This paper addresses the design of a sliding mode based extremum-seeking controller for a class of single-input–single-output (SISO) uncertain nonlinear systems with unmatched and state-dependent strong nonlinearities. We demonstrate that it is possible to achieve an arbitrarily small neighborhood of the desired optimal point using only output-feedback. The key idea is the combination of a periodic switching function with a norm state observer. As an important advantage, we show that the proposed scheme achieves extremum-seeking for all initial conditions, i.e., the real-time optimization algorithm has global convergence properties. An application to a simple nonderivative optimizer illustrates the viability of the proposed approach.     

The Spotification of public service media

This article investigates contemporary cultural policy reforms enabled by paid digital media distribution services, taking the case of the integration of Spotify into the Swedish public media system. Specifically, it reflects on the conflicts arising over the prioritization of digital distribution over cultural preservation, during the gradual substitution of the Spotify digital services for the services provided by the traditional material media archive, the Grammofonarkivet. It considers the factors influencing changes in the Swedish cultural policy environment and the nature of the complaints and human rights claims made by employees of the Grammofonarkivet to UNESCO regarding its structural transformation. It also postulates a “Spotification” model of public service media emerging in Sweden but potentially affecting other countries with public media systems served by traditional media archives.     

Sex-Related Responses to Eccentric-Only Resistance Training in Knee-Extensors Muscle Strength and Architecture

Purpose: The present study aimed to investigate whether or not eccentric-only training induced different sex-related adaptations in vastus lateralis muscle architecture and knee extensors strength. Methods: Thirteen healthy women and 13 healthy men were recruited. Vastus lateralis pennation angle, fascicle length, and muscle thickness, as well as knee extensors eccentric, isometric, and concentric peak torque and one-repetition maximum (1RM) were measured. Both women and men underwent a unilateral iso-load knee-extension eccentric-only training with 120% of the concentric 1RM, consisting of 4 sets × 10 repetitions twice a week for a total of 8 weeks. Results: Pennation angle increased in women (+ 14%, 95% CI [10, 17], effect size [ES] = 1.54) but not in men (+ 5%, 95% CI [?1, 11], ES = 0.28), while fascicle length increased in both women (+ 7%, 95% CI [4, 10], ES = 1.02) and men (+ 12%, 95% CI [8, 16], ES = 1.82) and muscle thickness increased in women (+ 13%, 95% CI [8, 18], ES = 1.11) and men (+ 11%, 95% CI [7, 15], ES = 0.89). In both women and men, eccentric (18%, 95% CI [11, 25], ES = 0.96, and 16%, 95% CI [9, 22], ES = 0.82, respectively), isometric (17%, 95% CI [11, 23], ES = 0.53, and 17%, 95% CI [10, 24], ES = 0.62), concentric (12%, 95% CI [7, 16], ES = 0.49, and 9%, 95% CI [5, 13], ES = 0.42) peak torque and 1RM (10%, 95% CI [6, 14], ES = 0.53, and 10%, 95% CI [5, 15], ES = 0.50) similarly increased after the intervention. Conclusions: This study showed that the adaptations in strength are not sex-dependent, but the increases in pennation angle only in women suggest that the changes in muscle architecture may depend on sex.     

P.S.: I Survived: An Activism Project to Increase Student and Community Trauma Awareness

Social work students created a community activism project to raise awareness about trauma prevalence and impact. Trauma theory describes silencing as the mechanism that hinders individual and community healing. Therefore, students sought to create an interactive opportunity to heighten trauma visibility on campus. They created a physical mailbox and invited community members respond to the prompt, “I am a survivor because …” and to read others’ responses. Through the project, students were able to document participants’ trauma experiences, increase community trauma awareness, and enhance their own learning. Moreover, the authors believe that this assignment successfully fostered student integration of micro and macro social work skills.     

Implementing Gender Equity Policies in a University Sport Organization: Competing Discourses from Enthusiasm to Resistance

Gender policies in sports have expanded considerably in most countries in recent decades. Nevertheless, the implementation of these policies in sports organizations is by no means an automatic process. This article explores what happens when gender equity policies are applied in an university sports organization. Participatory action research over a four-year period was developed by the authors to increase the participation of women, and it also aimed to explore the perceptions and thoughts of key actors regarding equity actions. The analysis shows the participation numbers in the specific promotional campaign and reveals a wide range of responses among staff, ranging from enthusiasm and interest to resistance and fear. Gender equity actions often encounter resistance which cannot, and should not, be ignored. This article highlights certain forms of resistance that proposals of this kind should be prepared for.