10,043 research outputs found
Information Literacy Instruction in an English Capstone Course: A Study of Student Confidence, Perception, and Practice
An English professor and an instruction librarian at the University of New Hampshire at Manchester felt that the college\u27s new English Capstone course for majors provided a unique opportunity to assess the information literacy skill levels of graduating English majors. They therefore engaged in a three-year study to evaluate the IL competency of these students, to gauge their perceptions of library instruction provided during the Capstone course and throughout their academic careers, and to determine students\u27 confidence and self-efficacy with respect to these skills. The researchers sought to determine the ways in which the IL program for English majors effectively met established IL goals and to identify areas for improvement
Combinatorial batch codes
In this paper, we study batch codes, which were introduced by Ishai, Kushilevitz, Ostrovsky and Sahai in [4]. A batch code specifies a method to distribute a database of [n] items among [m] devices (servers) in such a way that any [k] items can be retrieved by reading at most [t] items from each of the servers. It is of interest to devise batch codes that minimize the total storage, denoted by [N] , over all [m] servers.
We restrict out attention to batch codes in which every server stores a subset of the items. This is purely a combinatorial problem, so we call this kind of batch code a ''combinatorial batch code''. We only study the special case [t=1] , where, for various parameter situations, we are able to present batch codes that are optimal with respect to the storage requirement, [N] . We also study uniform codes, where every item is stored in precisely [c] of the [m] servers (such a code is said to have rate [1/c] ). Interesting new results are presented in the cases [c = 2, k-2] and [k-1] . In addition, we obtain improved existence results for arbitrary fixed [c] using the probabilistic method
Gravity-driven draining of a thin rivulet with constant width down a slowly varying substrate
The locally unidirectional gravity-driven draining of a thin rivulet with constant width but slowly varying contact angle down a slowly varying substrate is considered. Specifically, the flow of a rivulet in the azimuthal direction from the top to the bottom of a large horizontal cylinder is investigated. In particular, it is shown that, despite behaving the same locally, this flow has qualitatively different global behaviour from that of a rivulet with constant contact angle but slowly varying width. For example, whereas in the case of constant contact angle there is always a rivulet that runs all the way from the top to the bottom of the cylinder, in the case of constant width this is possible only for sufficiently narrow rivulets. Wider rivulets with constant width are possible only between the top of the cylinder and a critical azimuthal angle on the lower half of the cylinder. Assuming that the contact lines de-pin at this critical angle (where the contact angle is zero) the rivulet runs from the critical angle to the bottom of the cylinder with zero contact angle, monotonically decreasing width and monotonically increasing maximum thickness. The total mass of fluid on the cylinder is found to be a monotonically increasing function of the value of the constant width
Distinct difference configurations: multihop paths and key predistribution in sensor networks
A distinct difference configuration is a set of points in Z2 with the property that the vectors (difference vectors) connecting any two of the points are all distinct. Many specific examples of these configurations have been previously studied: the class of distinct difference configurations includes both Costas arrays and sonar sequences, for example. Motivated by an application of these structures in key predistribution for wireless sensor networks, we define the k-hop coverage of a distinct difference configuration to be the number of distinct vectors that can be expressed as the sum of k or fewer difference vectors. This is an important parameter when distinct difference configurations are used in the wireless sensor application, as this parameter describes the density of nodes that can be reached by a short secure path in the network. We provide upper and lower bounds for the k-hop coverage of a distinct difference configuration with m points, and exploit a connection with Bh sequences to construct configurations with maximal k-hop coverage. We also construct distinct difference configurations that enable all small vectors to be expressed as the sum of two of the difference vectors of the configuration, an important task for local secure connectivity in the application
Two-dimensional patterns with distinct differences; constructions, bounds, and maximal anticodes
A two-dimensional (2-D) grid with dots is called a configuration with distinct differences if any two lines which connect two dots are distinct either in their length or in their slope. These configurations are known to have many applications such as radar, sonar, physical alignment, and time-position synchronization. Rather than restricting dots to lie in a square or rectangle, as previously studied, we restrict the maximum distance between dots of the configuration; the motivation for this is a new application of such configurations to key distribution in wireless sensor networks. We consider configurations in the hexagonal grid as well as in the traditional square grid, with distances measured both in the Euclidean metric, and in the Manhattan or hexagonal metrics. We note that these configurations are confined inside maximal anticodes in the corresponding grid. We classify maximal anticodes for each diameter in each grid. We present upper bounds on the number of dots in a pattern with distinct differences contained in these maximal anticodes. Our bounds settle (in the negative) a question of Golomb and Taylor on the existence of honeycomb arrays of arbitrarily large size. We present constructions and lower bounds on the number of dots in configurations with distinct differences contained in various 2-D shapes (such as anticodes) by considering periodic configurations with distinct differences in the square grid
Cognitive change and participation in training groups: a personal construct psychology approach to learning in training groups
Four training groups were studied. The first called The Field Study was part of a company's training programme and took the form of a one week residential training group. The participants were 26 adults and 6 trainers. The training occurred in three small groups with two trainers each. The remaining three groups called Experimental Training Groups, each comprised 10 students and involved 2 hours per week for 4 weeks with a total participation time of about 10 hours. The field study was used to examine the feasibility of using Personal Construct Psychology to understand and measure cognitive change, and to isolate significant variables which required closer examination. The experimental training groups were conducted in a laboratory setting where the processes could be closely measured by observation and video recording. Specific hypothesis suggested by the field study were examined in detail here. Both processes and outcomes were measured. In the field study the process measures were obtained from trainer ratings of: verbal participation, influence, giving information, and seeking information. In the experimental groups the process measures were obtained from videotape recordings of the interactions coded with Bales' Interaction Process Analysis. Measures of cognitive change were obtained from content and structural analyses of two rating forms of the Repertory Grid. In the first grid, change was the difference between the structure with the individuals constructs before the training group, and the structure with these constructs rerated afterwards. The second grid contained fresh constructs. Personality measures in the experimental groups were obtained using Caine & Foulds Hostility and Direction of Hostility (HDHQ), and a Test of Social Skills derived from Section 2B of California Test of Personality. The aims were: 1. to investigate the impact of the experiences on the cognitions of the participants. 2. to unravel the interaction processes associated with any cognitive changes detected. The importance of cognitive change and its relationship with interaction processes in the group is discussed. The uniformity assumptions were questioned and diversity in individual learning was searched for. Three distinct types of change in the participants' cognitions were identified and described. The natures of the interactions associated with each type are delineated
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