Activity recognition is a widely researched area with applications in health care, security and other domains. With each recognition system considering its own set of activities and sensors, it is difficult to compare the performance of these different systems and more importantly it makes the task of selecting an appropriate set of technologies and tools for recognizing an activity challenging. In this work-in-progress paper we attempt to characterize activities in terms of a complexity measure. We define activity complexity along three dimensions – sensing, computation and performance and illustrate different parameters that parameterize these dimensions. We look at grammars for representing activities and use grammar complexity as a measurement for activity complexity. Then we describe how these measurements can help evaluate the complexity of activities of daily living that are commonly considered by various researchers.

Lack of context in information is a serious problem for knowledge-workers. Effective utilization of computational aids for supporting knowledge-workers require a rich understanding of the nature of context of information and related knowledge-works. It also needs specifications about how such understanding can be leveraged in computer-based systems. In this paper we propose a holistic model of context of knowledge-works and information created in course of their performances. We also demonstrate with an example how such a model can be used as basis for developing a formal, machine-deployable specification of activity context.

The goal of representing context in a mixed initiative sys-tem is to model the information at a level of abstraction that is actionable for both the human and automated system. A potential solution to this problem is the Context for Human and Automation Teams (CHAT). This paper introduces the CHAT model and provides example implementations from several different applications such as task scheduling tech-niques, multi-agent systems, and human-robot interaction.

Representing context information associated with people and digital devices performing activities is presented using a formal systems model based on a legal but simplified version of set theory. A five set Venn diagram, the PentaVenn diagram, allows analysts to work using a graphical logic rather than with equations. Model symmetry is shown to facilitate identifying different types of context, tangible and intangible.

This position paper describes the Activity-Based Computing (ABC) project which has been ongoing in Denmark since 2003. Originally, the project took its outset in the design of a pervasive computing platform suited for the mobile, collaborative, and time-critical work of clinicians in a hospital setting. Out of this grew a conceptual framework, a set of six ABC principles, and a programming and runtime framework for the development of activity-based computing infrastructures and applications. Lately, these principles and technologies have been successfully moved to other application areas, and is now used to design and implement activity-based computing support for work in a biology laboratory and for global software development.

We study the theoretical advantages of active learning over passive learning. Specifically, we prove that, in noise-free classifier learning for VC classes, any passive learning algorithm can be transformed into an active learning algorithm with asymptotically strictly superior label complexity for all nontrivial target functions and distributions. We further provide a general characterization of the magnitudes of these improvements in terms of a novel generalization of the disagreement coefficient. We also extend these results to active learning in the presence of label noise, and find that even under broad classes of noise distributions, we can typically guarantee strict improvements over the known results for passive learning.

This paper proposes a robust approach for face detection and gender classification in color images. Previous researches about gender recognition suppose an expensive computational and time-consuming pre-processing step in order to alignment in which face images are aligned so that facial landmarks like eyes, nose, lips, chin are placed in uniform locations in image. In this paper, a novel technique based on mathematical analysis is represented in three stages that eliminates alignment step. First, a new color based face detection method is represented with a better result and more robustness in complex backgrounds. Next, the features which are invariant to affine transformations are extracted from each face using scale invariant feature transform (SIFT) method. To evaluate the performance of the proposed algorithm, experiments have been conducted by employing a SVM classifier on a database of face images which contains 500 images from distinct people with equal ratio of male and female.

Behind every search query is a high-level mission that the user wants to accomplish.  While current search engines can often provide relevant information in response to well-specified queries, they place the heavy burden of making a plan for achieving a mission on the user. We take the alternative approach of tackling users' high-level missions directly by introducing a human computation system that generates simple plans, by decomposing a mission into goals and retrieving search results tailored to each goal. Results show that our system is able to provide users with diverse, actionable search results and useful roadmaps for accomplishing their missions.

The aim of a modern Building Automation System (BAS) is to enhance interactive control strategies for energy efficiency and user comfort. In this context, we develop a novel control algorithm that uses a stochastic building occupancy model to improve mean energy efficiency while minimizing expected discomfort. We compare by simulation our Stochastic Model Predictive Control (SMPC) strategy to the standard heating control method to empirically demonstrate a 4.3% reduction in energy use and 38.3% reduction in expected discomfort.

We consider the general problem of finding the minimum weight $\bm$-matching on arbitrary graphs. We prove that, whenever the linear programming (LP) relaxation of the problem has no fractional solutions, then the belief propagation (BP) algorithm converges to the correct solution. We also show that when the LP relaxation has a fractional solution then the BP algorithm can be used to solve the LP relaxation. Our proof is based on the notion of graph covers and extends the analysis of (Bayati-Shah-Sharma 2005 and Huang-Jebara 2007}. These results are notable in the following regards: (1) It is one of a very small number of proofs showing correctness of BP without any constraint on the graph structure. (2) Variants of the proof work for both synchronous and asynchronous BP; it is the first proof of convergence and correctness of an asynchronous BP algorithm for a combinatorial optimization problem.