In this work, we show how a variable-length genetic algorithm naturally evolves populations whose mean chromosome length grows shorter over time. A reduction in chromosome length occurs when selection is absent from the GA. Specifically, we divide the mating space into five distinct areas and provide a probabilistic and empirical analysis of the ability of matings in each area to produce children whose size is shorter than the parent generation's average size. Diversity of size within a GA's population is shown to be a necessary condition for a reduction in mean chromosome length to take place. We show how a finite variable-length GA under random selection pressure uses 1) diversity of size within the population, 2) over-production of shorter than average individuals, and 3) the imperfect nature of random sampling during selection to naturally reduce the average size of individuals within a population from one generation to the next. In addition to our findings, this work provides GA researchers and practitioners with 1) a number of mathematical tools for analyzing possible size reductions for various matings and 2) new ideas to explore in the area of bloat control.

This study compared three methods of selecting the best discriminating test items and the resultant test reliability of mastery/nonmastery classifications. These three methods were (a) the agreement approach, (b) the phi coefficient approach, and (c) the random selection approach. Test responses from 1,836 students on a 50-item physical science test were used, from which 90 distinct data sets were generated for analysis. These 90 data sets contained 10 replications of the combination of three different sample sizes (75, 150, and 300) and three different numbers of test items (15, 25, and 35). The results of this study indicated that the agreement approach was an appropriate method to be used for selecting criterion-referenced test items at the classroom level, while the phi coefficient approach was an appropriate method to be used at the district and/or state levels. The random selection method did not have similar characteristics in selecting test items and produced the lowest reliabilities, when compared with the agreement and the phi coefficient approaches.

The addition of random selection to our arsenal of methods for selecting political officials would enhance performance against norms of representative democracy. I employ historical and analytic methods to explore the nature of sortition and its relation to political equality, rational decision-making, and legitimate representation. Sortition both expresses a democratic commitment to political equality and facilitates improved performance under this democratic norm. It can be rational to eschew reasons in the process of selecting political officials, and decision-making bodies chosen randomly can be expected to make good decisions. I also address concerns stemming from representative norms, surrounding random selection of officials, arguing that random selection can enhance the resemblance and responsiveness of representatives. Finally, I detail some possibilities for institutional arrangements that would deliver the benefits of sortition while addressing the challenges it presents. / text

The current study sought to add to the literature on applying interdependent group-oriented contingency systems with randomized components to academic performance. This study expanded previous work, which has only examined effects on elementary classrooms and students with disabilities, by implementing a similar intervention within a general education, secondary classroom. Given the restricted time that teachers have to learn and implement interventions, while simultaneously carrying out all their additional responsibilities in the classroom, it is necessary for school psychologists to consider these limitations when recommending interventions. In previous work involving interdependent group-oriented contingencies, the delivery of reinforcement has been relatively immediate. While this is an ideal arrangement, it may be infeasible for middle and high school teachers to ensure reinforcement of academic performance occurs immediately within the class period. This study examined whether the delivery of reinforcement can be delayed within an interdependent group-oriented contingency system and still improve the academic performance of students in the classroom, which will allow the teacher more time for evaluating the quality of student work and, in turn, impact the acceptability of the intervention. One middle school, general education classroom served as the setting for this study. Academic performance data, including in-class work completion and accuracy rates, were collected class-wide and data on social behavior variables were gathered for 3 students exhibiting moderate to high levels of off-task behavior, based on teacher perception. An alternating treatments design was employed with two intervention conditions: one condition included immediate reinforcement and the other involved delivering reinforcement to students a day later. The interdependent group-oriented contingency intervention implemented included procedures for randomly selecting target behaviors, criteria, and reinforcers.

Collaborative Beamforming (CB) has been introduced in Wireless Sensor Networks (WSNs) context as a long-distance and power-efficient communication scheme. One challenge for CB is the randomness of sensor node locations where different network realizations result in different CB beampatterns. First, we study the effect of sensor node spatial distribution on the CB beampattern. The characteristics of the CB beampattern are derived for circular Gaussian distributed sensor nodes and compared with the case of uniform distributed sensor nodes. It is shown that the mainlobe behavior of the CB beampattern is essentially deterministic. This suggests that the average beampattern characteristics are suitable for describing the mainlobe of a sample beampattern. However, the CB beampattern sidelobes are random and highly depends on the particular sensor node locations. Second, we introduce the multi-link CB and address the problem of random sidelobes where high level sidelobes can cause unacceptable interference to unintended Base Stations or Access Points (BSs/APs). Centralized sidelobe control techniques are impractical for distributed sensor nodes because of the associated communication overhead for each sensor node. Therefore, we propose a node selection scheme as an alternative to the centralized sidelobe control which aims at minimizing the interference at unintended BSs/APs. Our algorithm is based on the use of the inherent randomness of the channels and a low feedback that approves/rejects tested random node combinations. The performance of the proposed algorithm is analyzed in terms of the average number of trials and the achievable interference suppression and transmission rate. Finally, we study CB with power control aiming at prolonging the lifetime of a cluster of sensor nodes in the WSN. The energy available at different sensor nodes may not be the same since different sensor nodes may perform different tasks and not equally frequently. CB with power control can be used to balance the individual sensor nodes' lifetimes. Thus, we propose a distributed algorithm for CB with power control that is based on the Residual Energy Information (REI) at each sensor node while achieving the required average SNR at the BS/AP. The effectiveness of the proposed CB with power control is illustrated by simulations. / Communications

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The Swedish school has the task of allowing all pupils to develop their ability to verbally communicate in the classroom. Through communicating verbally, the pupils will gain confidence in their linguistic ability in the social-science subjects. The purpose of this study is to investigate how a random selection with “ice cream sticks” can help to create a dialogic classroom, and how the participants perceive this type of teaching method, and if there is possible change in communicating verbally. The questions the study will answer are:  ·       How do the teacher's questions and responses to the student responses affect student participation? ·       To what extent does mutual respect arise from classroom dialogue? ·       How do pupils and class teachers experience the random selection at the beginning and end of a period of three weeks? ·       To what extent and in what way has the changed way of teaching contributed to a dialogical classroom in the social-science subjects?   This survey includes pupils and teachers from two classes in grade four and five. The qualitative methods used in this survey are observations and interviews. The material has been analyzed using theories about how dialogue is created in the classroom and how the teaching form with “ice cream sticks” can be organized. The result that emerged from this research is that with the help of the teaching style and the teachers' approaches, which is how they ask questions and how they respond to the students, the quantitative student participation has contributed to an increased classroom dialogue.

This thesis empirically examines how lobby groups and activists respond to innovative forms of public participation. The study centres on processes that foster a particular kind of deliberative governance including citizens’ juries, consensus conferences and planning cells. These deliberative designs bring together a panel of randomly selected lay citizens to deliberate on a specific policy issue for a few days, with the aim of providing decision makers with a set of recommendations. While policy makers worldwide are attracted to these novel participatory processes, little consideration has been given to how well they work alongside more adversarial and interest-based politics. This doctoral research project examines this interface by studying what these processes mean to different kinds of policy actors such as corporations, advocacy groups, government agencies, experts and professionals. These entities are collectively referred to in this thesis as ‘interest organisations’ because in some way they are seeking a specific policy outcome from the state – even government-based groups.¶ The empirical research in this thesis is based on comparative case studies of four deliberative design projects in Australia and Germany. The Australian cases include a citizens’ jury on waste management legislation and a consensus conference on gene technology in the food chain. The German case studies include a planning cells project on consumer protection in Bavaria, and a national consensus conference on genetic diagnostics. Together the cases capture a diversity of complex and contested policy issues facing post-industrialised societies. In each case study, I examine how relevant interest organisations responded to the deliberative forum, and then interpret these responses in view of the context and features of the case.¶ The picture emerging from the in-depth case studies is that interest organisations respond to deliberative designs in a variety of ways. Some choose to participate actively, others passively decline, and a few resort to strategic tactics to undermine citizens’ deliberations. The empirical research reveals that though responses are variable, most interest organisations are challenged by several features of the deliberative design model including: 1) that deliberators are citizens with no knowledge or association with the issue; 2) that experts and interest representatives are required to present their arguments before a citizens’ panel; and 3) that policy discussions occur under deliberative conditions which can expose the illegitimate use of power.¶ Despite these challenges, the paradox is that many interest organisations do decide to engage in lay citizen deliberations. The empirical research indicates that groups and experts value deliberative designs if they present an opportunity for public relations, customer feedback, or advocacy. Moreover, the research finds that when policy actors intensively engage with ‘ordinary’ citizens, their technocratic and elite ideas about public participation can shift in a more inclusive and deliberative direction.¶ The thesis finds that, on the whole, weaker interest organisations are more willing to engage with lay citizens than stronger organisations because they welcome the chance to influence public debate and decision makers. It appears that powerful groups will only engage in a deliberative forum under certain policy conditions, for example, when the dominant policy paradigm is unstable and contested, when public discussion on the issue is emerging, when policy networks are interdependent and heterogeneous, and when the broader social and political system supports public accountability, consensus and deliberation. Given that these kinds of policy conditions do not always exist, I conclude that tensions between interest organisations and deliberative governance will be common. In order to create more cooperative and productive interfaces, I recommend that interest organisations be better supported and integrated into citizens’ deliberations, and that steps be taken to safeguard forums from strategic attempts to undermine their legitimacy.¶ The thesis also sends out three key messages to democratic theorists. First, the empirical research shows that different kinds of groups and actors in civil society vary in their willingness and capacity to participate to public deliberation. Second, the deliberative design model demonstrates that partisan actors, such as interest organisations, will engage in public deliberation when they can participate as strategic deliberators. In this role partisans are not expected to relinquish their agendas, but present them as testimonies before a group of deliberators. Third, the empirical research in this thesis should bring home to theorists that deliberative forums are closely linked to the discursive context within which they operate.

There is a growing demand for studies applying quantitative methods to large-scale data sets for the purpose of evaluating the effects of educational reforms (UVK, 2010). In this thesis the statistical method, Propensity Score Analysis (PSA), is presented and explored in the evaluating context of an extensive educational initiative within science and technology education; the Science and Technology for All-program (NTA). The research question put forward reads; under what conditions are PSA-analyses a useful method when measuring the effects from a school improvement initiative in S &amp; T? The study considers the use of PSA when looking for long-term effects that could be measured, what to take into consideration to be able to measure this, and how this could be done. The baseline references (outcome variables) used in order to measure/evaluate the long-term effects from the studied program is students’ achievements in the national test (score and grades) and their grades in year 9. Some findings revealed regarding the object of study (long-term effects from using NTA) are also presented. The PSA method is found to be a useful tool that makes it possible to create artificial control groups when experimental studies are impossible or inappropriate; which is often the case in school education research. The method opens up for making use of the rich source of registry data gathered by authorities. PSA proves reliable and relatively insensitive to the effects of covariates and heterogeneous effecter if the number of samples is large enough. The use of PSA (or other statistical methods) also makes it possible to measure outcomes several years after treatment. There are issues of concern when using PSA. One is the obvious demand for organized collection of measurement data. Another issue of concern is the choice of outcome variables. In this study the chosen outcome variables (pupils’ score and grading in national tests and grades in year 9) open up for discussions regarding aspects that might not be reflected/measured in national tests and/or teachers’ grading. Findings regarding the long-term effects from using NTA) show significantly positive effects in physics on test scores (average increase 16.5%) and test grades, but not in biology and chemistry. In this study no significant effects are found for course grades. PSA approach has proved to be a reliable method. There is however a limitation in terms of the method's ability to capture more subtle aspects of learning. A combination of quantitative and qualitative approach when studying long-term effects from educational intervention is therefore suggested. / <p>QC 20131120</p>

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