Design and Evaluation of Menu Systems for Immersive Virtual Environments

Interfaces for system control tasks in virtual environments (VEs) have not been extensively studied. This paper focuses on various types of menu systems to be used in such environments. We describe the design of the TULIP menu, a menu system using Pinch Gloves™, and compare it to two common alternatives: floating menus and pen and tablet menus. These three menus were compared in an empirical evaluation. The pen and tablet menu was found to be significantly faster, while users had a preference for TULIP. Subjective discomfort levels were also higher with the floating menus and pen and tablet

On the Use of Menus in Sequential Common Agency

We illustrate, by means of two examples, why assuming the principals offer simple menus (i.e. collections of payoff-relevant alternatives) as opposed to more general mechanisms may preclude a complete characterization of the set of equilibrium outcomes in certain sequential contracting environments. We then discuss how refinements of the solution concept, or enrichments of the menus that allow for recommendations, may restore the possibility of using menus to obtain a complete equilibrium characterization.Sequential contracting, mechanism design, menus theorems.

Direct Mechanisms, Menus and Latent Contracts

In common agency games, one cannot characterize all equilibria by considering only direct mechanisms. In an attempt to overcome this difficulty, Peters [Econometrica, 2001]and Martimort and Stole [Econometrica, 2002] identified a class of indirect mechanisms (namely, menus) which are able to characterize every equilibrium. Unfortunately, menus are difficult to handle, and several methodologies have been proposed in the literature. Here, it is shown that, even if authors consider menus rather than simpler mechanisms, many equilibria described in the literature could have been characterized by direct incentive compatible mechanisms. Use of more sophisticated mechanisms was not necessary in these cases.Common Agency, Revelation Principle, Delegation Principle, Direct Mechanisms, Menus, Latent Contracts

Menus for Feeding Black Holes

Black holes are the ultimate prisons of the Universe, regions of spacetime where the enormous gravity prohibits matter or even light to escape to infinity. Yet, matter falling toward the black holes may shine spectacularly, generating the strongest source of radiation. These sources provide us with astrophysical laboratories of extreme physical conditions that cannot be realized on Earth. This chapter offers a review of the basic menus for feeding matter onto black holes and discusses their observational implications.Comment: 27 pages. Accepted for publication in Space Science Reviews. Also to appear in hard cover in the Space Sciences Series of ISSI "The Physics of Accretion onto Black Holes" (Springer Publisher

Optimal mechanisms with simple menus

We consider optimal mechanism design for the case with one buyer and two items. The buyer's valuations towards the two items are independent and additive. In this setting, optimal mechanism is unknown for general valuation distributions. We obtain two categories of structural results that shed light on the optimal mechanisms. The first category of results state that, under certain mild condition, the optimal mechanism has a monotone menu. In other words, in the menu that represents the optimal mechanism, as payment increases, the allocation probabilities for both items increase simultaneously. Applying this theorem, we derive a version of revenue monotonicity theorem that states stochastically superior distributions yield more revenue. Moreover, our theorem subsumes a previous result regarding sufficient conditions under which bundling is optimal. The second category of results state that, under certain conditions, the optimal mechanisms have few menu items. Our first result in this category says, for certain distributions, the optimal menu contains at most 4 items. The condition admits power (including uniform) density functions. Based on a similar proof of this result, we are able to obtain a wide class of distributions where bundling is optimal. Our second result in this category works for a weaker condition, under which the optimal menu contains at most 6 items. This condition includes exponential density functions. Our last result in this category works for unit-demand setting. It states that, for uniform distributions, the optimal menu contains at most 5 items. All these results are in sharp contrast to Hart and Nisan's recent result that finite-sized menu cannot guarantee any positive fraction of optimal revenue for correlated valuation distributions.Comment: 25 pages, 11 figure

Nutritional labelling in restaurants : whose responsibility is it anyway?

To explore consumer attitudes towards the potential implementation of compulsory nutritional labelling on commercial restaurant menus in the UK. This research was approached from the perspective of the consumer with the intention of gaining an insight into personal attitudes towards nutritional labelling on commercial restaurant menus and three focus groups consisting of participants with distinctly differing approaches to eating outside the home were conducted. The research suggests that while some consumers might welcome the introduction of nutritional labelling it is context dependent and without an appropriate education the information provided may not be understood anyway. The issue of responsibility for public health is unresolved although some effort could be made to provide greater nutritional balance in menus. Following this research up with a quantitative investigation, the ideas presented could be verified with the opinions of a larger sample. For example, a study into the reactions to nutritionally labelled menus in various restaurant environments. Consumers would react differently to the information being presented in a fine-dining restaurant than they would in popular catering or fast food. The obstacles faced by restaurants to provide not only nutritional information, but attractive, nutritious food are significant. Prior to this research there were few, if any, studies into the effects of food labelling on consumer choice behaviour in the context of hospitality management

Optimal Menu of Menus with Self-Control Preferences

Unlike consumers in standard economic models, the average consumer has to deal with temptation and go through a costly process of self-control. What if firms are aware of consumers’ self-control problems? Does it affect firms’ optimal selling strategies qualitatively? To answer this question, we use Gul–Pesendorfer utility formulation and characterize a monopolist’s optimal selling scheme in the otherwise standard model of nonlinear pricing. With costly self-control, the firm can earn more profits by offering multiple menus (or plans). If the temptation of consumers is to buy a larger quantity (or a good of higher quality), a set of menus can be designed to extract all the surplus: with those menus, consumption choices appear as if the consumers’ preferences were observable. If the temptation is to choose a smaller quantity (or spend more on outside options), full surplus extraction is not possible. The optimal scheme in this case charges entry fees since they work as a commitment device for consumers.Publicad

On Take It or Leave It Offers in Common Agency

If the agent's preference relation satisfies a strict monotonicity condition in common agency under the asymmetric information, the set of all equilibrium allocations in the menu game where menus of contracts are allowed coincides with the set of all equilibrium allocations in the single contract game where only single contracts are allowed.take it or leave it offers, menus, common agency, robust equilibrium allocations, mixed-strategy equilibrium

Optimal contracts with team production and hidden information: An experiment.

We devise an experiment to explore optimal contracts in a hidden-information context. A principal offers one of three possible contract menus to a team of two agents of unknown skill levels, with both agents’ participation needed for production. We observe numerous rejections of the more lopsided menus, and principals respond by offering more favorable menus. Apart from rejections,wesee almost complete separation in agent choices according to the agent types. Behavior converges towards a consensus in which one of the more equitable menus is proposed and agents accept a contract. The consensus menu differs across two treatments in which we vary the payoffs resulting from a rejection. We find strong evidence of social learning by low-skill agents (but only for low-skilled agents), in that a low-skill agent is more likely to reject a contract menu if her teammate rejected a contract menu in the previous period. In addition, low-skilled agents have a particularly adverse reaction to reduced wage offers.Experiment; Hidden information; Optimal contract; Production team; Wage rigidity;

The Efficiency of Pension Plan Investment Menus: Investment Choices in Defined Contribution Pension Plans

Few previous studies have explored whether defined contribution retirement saving plans offer sufficiently diversified investment menus, though it is likely that these menus significantly shape workers’ accumulations of retirement wealth. This paper assesses the efficiency and performance of 401(k) investment options offered by a large group of US employers. We show that most plans are efficient compared to market benchmark indexes. Three performance measures underscore the fact that these plans tend to offer a sensible investment menu, when measured in terms of the menus’ mean-variance efficiency, diversification, and participant utility. The key factor contributing to plan efficiency and performance has to do with the types of funds offered, rather than the total number of investment options provided.