Permissive Controller Synthesis for Probabilistic Systems

We propose novel controller synthesis techniques for probabilistic systems modelled using stochastic two-player games: one player acts as a controller, the second represents its environment, and probability is used to capture uncertainty arising due to, for example, unreliable sensors or faulty system components. Our aim is to generate robust controllers that are resilient to unexpected system changes at runtime, and flexible enough to be adapted if additional constraints need to be imposed. We develop a permissive controller synthesis framework, which generates multi-strategies for the controller, offering a choice of control actions to take at each time step. We formalise the notion of permissivity using penalties, which are incurred each time a possible control action is disallowed by a multi-strategy. Permissive controller synthesis aims to generate a multi-strategy that minimises these penalties, whilst guaranteeing the satisfaction of a specified system property. We establish several key results about the optimality of multi-strategies and the complexity of synthesising them. Then, we develop methods to perform permissive controller synthesis using mixed integer linear programming and illustrate their effectiveness on a selection of case studies

Expertise in map comprehension: processing of geographic features according to spatial configuration and abstract roles

Expertise in topographic map reading is dependent on efficient processing of geographical information presented in a standardised map format. Studies have supported the proposition that expert map readers employ cognitive schemas in which prototypical configurations held in long term memory are employed during the surface search of map features to facilitate map comprehension. Within the experts’ cognitive schemas, it is assumed that features are grouped according to spatial configurations that have been frequently encountered and these patterns facilitate efficient chunking of features during information processing. This thesis investigates the nature of information held in experts’ cognitive schemas. It also proposes that features are grouped in the experts’ schemas not only by their spatial configurations but according to the abstract and functional roles they perform. Three experiments investigated the information processing strategies employed by firstly, skilled map readers engaged in a map reproduction task and secondly, expert map readers engaged in a location comparison exercise. In the first and second experiments, skilled and novice map readers studied and reproduced a town map and a topographic map. Drawing protocols and verbal protocols provided insights into their information processing strategies. The skilled map readers demonstrated superior performance for reproducing contour related data with evidence of the use of cognitive schemas. For the third experiment, expert and novice map readers compared locations within map excerpts for similarities of boundary extents. Eye-gaze data and verbal protocols provided information on the features attended to and the participants’ search patterns. The expert group integrated features into their cognitive schemas according to the abstract roles they performed significantly more frequently than the novices. Both groups employed pattern recognition to integrate features for some of the locations. Within a similar experimental design the second part of the third experiment examined whether experts also integrated the abstract roles of remote features and village grouping concepts within their cognitive schemas. The experts again integrated the abstract roles of physical features into their schemas more often than novices but this strategy was not employed for either the remote feature or grouping categories. Implications for map design and future Geographic Information Systems are discussed

LiveRetro: Visual Analytics for Strategic Retrospect in Livestream E-Commerce

Livestream e-commerce integrates live streaming and online shopping, allowing viewers to make purchases while watching. However, effective marketing strategies remain a challenge due to limited empirical research and subjective biases from the absence of quantitative data. Current tools fail to capture the interdependence between live performances and feedback. This study identified computational features, formulated design requirements, and developed LiveRetro, an interactive visual analytics system. It enables comprehensive retrospective analysis of livestream e-commerce for streamers, viewers, and merchandise. LiveRetro employs enhanced visualization and time-series forecasting models to align performance features and feedback, identifying influences at channel, merchandise, feature, and segment levels. Through case studies and expert interviews, the system provides deep insights into the relationship between live performance and streaming statistics, enabling efficient strategic analysis from multiple perspectives.Comment: Accepted by IEEE VIS 202

Factors Which Influence Key Entry Speed On Hard and Soft Keyboards: Experience, Eye Behaviors and Finger Movements

Soft keyboards have become ubiquitous, especially with the introduction of the iPad. This study aims to determine for experienced touch typists whether there are characteristics of soft QWERTY keyboards that can make them easier to use and why those characteristics provide an advantage. Two characteristics would appear to be of central importance. First, hard keyboards provide home row positioning information that is not as easily provided by soft keyboards. Second, hard keyboards also provide auditory and tactile feedback when a key is depressed, something not generally provided with soft keyboards. In order to test the hypothesis that the absence of home row positioning and key strike feedback information can reduce expert touch typists’ speeds on soft keyboards, expert touch typists were run in two experiments. In Experiment 1, soft and hard keyboards in landscape and portrait mode were evaluated. The hard keyboards had the standard home row positioning and key strike feedback whereas the soft keyboards had neither. If these are important elements in typing speed, then experienced hard keyboard typists should type less quickly when using soft keyboards than when using hard keyboards. Moreover, if reducing the footprint of the keyboard, from landscape to portrait, requires more eye movements, then typists using both hard and soft keyboards should be slower when using the portrait size keyboard than when using the landscape size keyboard. Perhaps not surprisingly, experienced hard keyboard touch typists do less well when entering information on soft keyboards without home row positioning information or auditory feedback. Moreover, both groups appear to type more slowly in keyboards laid out in a portrait format than they do in keyboards laid out in a landscape format. In summary, the results from Experiment 1 suggest that both home row positioning information and auditory key strike feedback should speed performance. In Experiment 2, an attempt was made to determine just how much of a gain can be made in the typing speed of more experienced soft keyboard users if home row positioning information (tactile feedback), auditory feedback, or both are added. Participants were run in four conditions: auditory key strike feedback (with and without) was crossed with tactile home row positioning information (with and without). Participants included expert level hard keypad QWERTY touch typists who have had at least five hours’ typing experience with an iPad. Participants were given four passages to type, all of equal length and all balanced for letter frequency. Participants typed one passage in each of the four conditions. The passage sequence was counterbalanced across participants. Typing speeds for each of the passages was measured and averaged across participants within conditions. A repeated measures analysis of variance was used to determine whether there was a main effect of position or feedback. In order to determine why it is that home row positioning and key strike feedback alters performance, eye behaviors, movement times and task completion times are calculated. If home row position information is important, soft keyboards without this information may have a larger number of glances that a typist directs at the keyboard. These glances will help the typist determine either whether a finger is positioned over the correct home key (the launch key) or whether the location of the key to be typed next (the target key) is in the expected position. If key strike feedback is important, soft keyboards without this information should have longer movement times where the typists do not need to glance at the keyboard. This follows since the typist will process less quickly the fact that a finger has landed on a key. Key press and key release times will be included each time a character, number or spacebar is depressed or releases. The finger movement time between any pair of keys i and j will be derived from the key press and key release times. This time will be measured from the moment the finger leaves the launch key i until the moment that the finger arrives at the target key j. Task completion times were defined as the difference between the first key press in a passage and the last key release. Finger movement times, inter-keystroke intervals and task completion times were recorded using a program developed in JAVA 2SE. Eye movements are recorded with aid of an ASL Mobile EYE tracker. Analyses of the finger movement times and task completions times in Experiment 2 indicated that participants were fastest when both position information and auditory feedback were included. When just finger movement times are considered, there was a significant effect of auditory feedback but not of positioning information. This was what was expected given that the speed of finger movement times is arguably largely a function of how quickly a typist perceives that a movement has been completed, something that auditory feedback, but not positioning information provides. When just the task completion times were analyzed, position information had a significant effect. The effect of auditory feedback was only marginally significant. It was expected that both factors would be significant. Perhaps the power was too small. Finally, when the eye movements were analyzed, the total scanning time was shortest when both position information and auditory feedback were available. The effects of both were statistically significant. In summary, on the basis of the results from Experiment 1 it appeared likely that auditory feedback and positioning information accounted in part for the faster typing times of touch typists on hard keyboards as opposed to soft keyboards. In Experiment 2, this hypothesis was evaluated. Finger movement and task completion times were fastest when both auditory feedback and positioning information were present. The effect of auditory feedback appeared to impact only the finger movement times. The effect of both auditory feedback and positioning information appeared to impact the task completion times. However, the effect of auditory feedback on task completion times was only marginal. Finally, it was clear that much of the reduction in task completion times occurred because the time that the touch typists spent scanning the keyboard was smaller when both auditory feedback and positioning information was available. It is recommended in the future that soft keyboards have both sets of feedback available, auditory (through simulated key clicks) and tactile (through home row positioning information). The gains in typing speed with these additions were models (about 10%), considered over the entire population of users the impact could be considerable

Nexiwave case

Thesis (S.M. in Engineering and Management)--Massachusetts Institute of Technology, System Design and Management Program, 2009.Cataloged from PDF version of thesis.Includes bibliographical references (p. 82-83).Telecommunication technology has had a profound impact on our daily lives. It has enabled organizations to be more competitive by reducing the need for physical proximity and fostering collaboration. In recent years especially, data networks have been especially prominent, with the obvious example being the Internet. Work that was once conducted by phone and fax is now increasingly being done by VolP, e-mail and IM. For years telecommunication companies had focused in making available communication between person-to-person as well as multi-person and mobile communication, but none had focused on the content of the voice communication. This thesis presents a functioning product to address the needs of such users by applying a systems thinking approach to visualize and manage complexity through the whole process from the product idea generation to the business model. A detailed assessment of the users' needs and description of the product's user-centric design is provided. User experience design principles and legal constraints were considered throughout the development process. We propose to add value and differentiate the product by providing users with options to manage the content of their calls. At the most basic level, we give free audio-to-text transcripts with built-in features that could users save time and be more productive. nexiwave was built using principles promulgated in the System Design and Management Program classes.by Cynthia Munoz Jugo [and] Benjamin Jiang.S.M.in Engineering and Managemen

Survey of the State of the Art in Natural Language Generation: Core tasks, applications and evaluation

This paper surveys the current state of the art in Natural Language Generation (NLG), defined as the task of generating text or speech from non-linguistic input. A survey of NLG is timely in view of the changes that the field has undergone over the past decade or so, especially in relation to new (usually data-driven) methods, as well as new applications of NLG technology. This survey therefore aims to (a) give an up-to-date synthesis of research on the core tasks in NLG and the architectures adopted in which such tasks are organised; (b) highlight a number of relatively recent research topics that have arisen partly as a result of growing synergies between NLG and other areas of artificial intelligence; (c) draw attention to the challenges in NLG evaluation, relating them to similar challenges faced in other areas of Natural Language Processing, with an emphasis on different evaluation methods and the relationships between them.Comment: Published in Journal of AI Research (JAIR), volume 61, pp 75-170. 118 pages, 8 figures, 1 tabl