Contributions in Merlin

Mobile learning exposes learning to the natural environment. If this environment is large, the learners have to navigate to find the learning objects or to explore the environment. Current mobile learning systems provide only minimal navigational support. Prior studies report that conventional pedestrian information systems are not suited to mobile learning, as the learners focus too much on the navigation system. In this paper we analyze issues in navigational support and provide evidence for the lack of support in current systems. Then we propose and evaluate how mobile learning systems can not only provide better navigation support, but also prevent the focus problem. The tested concepts include using an aura to visualize the accuracy, using history visualization for orientation and browsing support, and using information pull to focus more on the environment. Recommendations for further research conclude the paper.

It is common practice for firms in a variety of industries to specify bonus pools that are available for distribution among a group of managers. While the actual size of the bonus pool may vary with the realization of certain financial metrics, for example, earnings growth or Return-on-Investment, the essential property of bonus pools is that the firm retains discretion in how the overall pool is divided among the target group of managers. An important advantage of discretionary bonus payments is that the persons in charge of administering the bonus pool are in a position to incorporate subjective, non-verifiable indicators of individual performance that would be impossible to specify contractually as part of an explicit incentive scheme. This paper synthesizes several strands of the recent principal-agent literature that have explored the structure and the relative efficiency of discretionary bonus pools. Our analysis is framed around a number of recurring themes. These include the value of subjective performance indicators for contracting purposes, the loss associated with subjective rather than objective information, and finally, the degree to which bonus pools entail more compression in the amounts of bonuses paid to managers.

null

In this article, we define the notion of a filtration and the related notion of the usual hypotheses. We then explain the problem of enlargements of filtrations: how are (semi)martingales affected under a change of filtrations? We state the main theorems in the classical frameworks of initial and progressive enlargements of filtrations. In the case of initial enlargements of filtrations, we state the well known Jacod's condition and in the framework of progressive enlargements of filtrations, we give the decomposition of a local martingale in the larger filtration. We finally specialize to the case of immersed filtrations, which is very widely used in credit risk modeling, and study the effect of a combination of changes of filtration and probability measure in this situation.

New restaurants often do not manage to succeed within a reasonable amount of time. Exotic restaurants especially face the problem that price promotions may not attract new customers because prospective customers might associate very low prices for unfamiliar food with a high functional risk. This paper describes how Pay-What-You-Want (PWYW), a new pricing mechanism, was successfully implemented at Kish, a moderately priced Persian restaurant in downtown Frankfurt. After the initial testing phase, which had the characteristics of a promotional offer, the restaurant decided to permanently offer its buffet lunch under PWYW conditions. We report the long-term effects of this decision as well as a simulation demonstrating that profitability is mainly based on ‘trading up’ the continuous inflow of new customers to the more profitable dining offer where prices are fixed.

Brand-nonspecific retailer coupons that entitle customers to assortment-wide discounts appeal in similar ways to national brand (NB) and private label (PL) users. The latter may be considered an attractive target group because they express high levels of deal proneness. However, it is unclear how assortment-wide retailer coupons affect customers' purchase behavior. In particular, nothing is known about how PL users behave during coupon promotions. The authors deal with these issues by conducting a large-scale field experiment (N = 28,000). They find that assortment-wide coupons increase both segments' (PL vs. NB users) profitability but that the route to increased profitability is different for the two groups. In the group of PL users, segment-level profitability is mainly driven by additional customers who would not have made a purchase in the absence of the promotion. On the contrary, in the segment of NB users, individual profitability increases because customers trade up to more expensive brands and/or products. Based on the differences in response behavior, the authors derive segment-specific managerial recommendations and emphasize that different promotional aims should be associated with PL and NB users.

Issues of segmentation and positioning have always been at the heart of marketing management. In recent years, much methodological progress has been made in order to carry out these two tasks simultaneously, that is, to combine certain types of clustering algorithms with appropriate multidimensional scaling or unfolding procedures. When trying to provide managers with a tool to support marketing decision-making in segmentation and positioning, the ease of use and the visual quality of results must be emphasized. This paper provides a state-of-the-art review of alternative graphical formats designed to assist strategic management. It focuses on three aspects, namely, (I) representing competitive market structures, (II) illustrating preferences for product attributes, and (III) describing customer heterogeneity at the individual as well as segment-specific levels; this paper also explores the interrelations among these aspects. The benefits and limitations of different approaches are discussed, and graphical examples are provided. Advances in academic research are contrasted with the information requirements of marketing managers. Finally, recommendations on the applicability of these alternatives for practical use are offered, and issues for further research are specified.

Transcranial magnetic stimulation (TMS) can be used for studying causal effects on visual phenomenology. Occipitally delivered TMS pulses when applied after a brief spatially extended visual reference stimulus induce a localized degrading effect on the visual quality of the reference, a subjective darkening called scotoma. The stability of the subjective characteristics of artificial scotomas has not been studied with advanced neuronavigation of TMS. In 3 experiments we studied the size and relative contrast of TMS-induced scotomas and looked for possible adaptation effects to TMS delivered to the same cortical location for many successive trials. MRI-based neuro-navigated biphasic single-pulse stimulation was used to show that (i) ISI values leading to scotomas in all individual subjects extend over a wide range of time intervals from 35 ms to 199 ms, (ii) the size of and relative decrease of contrast of scotoma area remained stable over multiple stimulations, and (iii) TMS effect on scotomas was location-specific so that carry-over effects from temporarily changed TMS location to another hemisphere were absent - returning back with stimulation to the original site from a temporarily changed site led to the previous value of scotoma expression.