On tangible user interfaces,humans and spatiality

Like the prehistoric twig and stone, tangible user interfaces (TUIs) are objects manipulated by humans. Tangible user interface success will depend on how well they exploit spatiality, the intuitive spatial skills humans have with the objects they use. In this paper, we carefully examine the relationship between humans and physical objects, and related previous research. From this examination, we distill a set of observations and turn these into heuristics for incorporation of spatiality into TUI application design, a cornerstone for their success. Following this line of thought, we identify spatial TUIs, the subset of TUIs that mediate interaction with shape, space and structure. We then examine several existing spatial TUIs using our heuristics.     

Effects of design flow and treatment level on construction and operation costs of municipal wastewater treatment plants and their implications on policy making

Construction costs of 55 municipal wastewater treatment plants in Israel (secondary, advanced secondary, and advanced treatment) were analysed in order to derive cost functions expressing the effects of design flow and treatment level on construction costs. Three equations were derived (statistically significant, p<0.01), one for each treatment level. These indicate that economy of scale may become weaker as treatment level rises. Analysis of the distribution of construction costs revealed negative correlation (p<0.05) between the proportional cost of civil engineering and design flow, positive correlation (p<0.05) between the proportional cost of elecromechanical equipment and design flow, and no correlation between the proportional cost of electricity and control and design flow. Operation costs were found to be 20–70% more sensitive than construction costs to treatment level. The share of operation costs as part of the total annual costs was found to increase both with design flow and treatment level, whereas the share of construction costs concurrently decreased. The implication of the findings on policy, and consequently on treatment plants performance is discussed in the last part of the paper.     

A programming approach to mathematics

This article presents an attempt to employ a programming approach to mathematical formalization. Six self-instructional units (120 instructional hours) have been developed for the Open University in Israel. This material was tried on three different types of populations: (a) bright high school students (11th–12th grade, A-level mathematics), (b) mathematics teachers with a programming background, and (c) university students studying mathematics, natural sciences and engineering. The results indicated that the programming approach is complementary to high school and university mathematics. The opportunity to explore, the algorithmic approach to mathematical operations and the visualization of mathematical objects and processes facilitates mathematical understanding and insights. It was most beneficial to the majority of the students who perform on a moderate level of abstraction. The course was less advantageous to those who have a very abstract way of perceiving mathematics or to those who are interested in mathematics only on a technical level. However, the vast majority of students gained new ways of understanding mathematical topics such as functions, curves, probability, game theory, recursive functions, envelopes, tiling, curve fitting, etc. They gained, as well, new strategies of using microcomputers to solve and further explore many mathematical problems which they could not solve before.     

Performance improvement analysis of boiling water reactors by incorporation of hydride fuel

The feasibility of improving the neutronic characteristics of boiling water reactors (BWR) by using U–Zr hydride fuel is studied. Several modified BWR fuel assembly designs are considered. These include designs in which hydride fuel rods replace water rods only, replace water rods and a fraction of the oxide fuel rods, replace oxide fuel in the upper half of all the fuel rods, and replace all the oxide fuel in the assembly. It is found that replacement of at least half of the oxide fuel rods in the fuel assembly by U–ZrH_1.6 fuel might simultaneously improve the performance of BWR in three ways: (a) Increasing the energy extracted per fuel assembly and the cycle length by up to 10%. (b) Reducing the uranium ore and SWU requirements by approximately 10%. (c) Reducing the negative void coefficient of reactivity by, at least, 50%. It is also found that replacement of all the oxide fuel by hydride fuel opens interesting new options for the design of BWR fuel assemblies. The net result might be simplified assembly designs that can generate significantly more energy while featuring small negative void coefficient of reactivity. U–ThH₂ fuel appears to be even more promising than U–ZrH_1.6. For the potential benefits from hydride fuel to be realized, a clad material that is not permeable to hydrogen and is not as neutron absorbing as stainless steel needs to be developed.     

Disassembly analysis through time estimation and other metrics

This paper examines the problem of assessing product ease of disassembly for recycling in light of the broader issue of manufacturability evaluation. The disassembly time estimation method outlined here is shown to provide one of several needed metrics for use during product design. Moreover, the ability to estimate process time provides the foundation upon which other metrics can be developed. The evaluation based on disassembly time is demonstrated on an electric drill example, and the difficulties associated with generating other disassemblability metrics are discussed.     

A new model of lexical choice for nouns1

Natural language generation systems should choose nouns by searching for lexical units that (i) are known to the user; (ii) truthfully describe the object being lexicalised; (iii) convey sufficient information to fulfill the system's underlying communicative goals; and (iv) are maximal under a lexical preference function. This model of lexical choice allows a clean separation to be made between what the system knows about the object being lexicalized and what it wishes to communicate about this object. The model also allows lexical choice to be biased towards basic-level and other preferred lexical units. Les systèmes de génération du langage naturel devraient choisir des noms en recherchant des unités lexicales (i) qui soient connues de ľutilisateur, (ii) qui décrivent fidèlement ľobjet soumis à un traitement lexical, (iii) qui transmettent suffisamment ?information pour répondre aux objectifs de communication du système, et (iv) qui soient maximales dans une fonction de préférence lexicale. Ce modéle de choix lexical permet une nette séparation entre ce que le système sait à propos de ľobjet soumis à un traitement lexical et ce qu'il souhaite communiquer à propos de cet objet. Le modèle permet également au choix lexical ?avoir un préjugé vis-à-vis les unités lexicales de niveau de base et autres unités lexicales préférées.