Network reachability of real-world contact sequences

We use real-world contact sequences, time-ordered lists of contacts from one person to another, to study how fast information or disease can spread across network of contacts. Specifically we measure the reachability time -- the average shortest time for a series of contacts to spread information between a reachable pair of vertices (a pair where a chain of contacts exists leading from one person to the other) -- and the reachability ratio -- the fraction of reachable vertex pairs. These measures are studied using conditional uniform graph tests. We conclude, among other things, that the network reachability depends much on a core where the path lengths are short and communication frequent, that clustering of the contacts of an edge in time tend to decrease the reachability, and that the order of the contacts really do make sense for dynamical spreading processes.Comment: (v2: fig. 1 fixed

System Resource Sharing for Synchronous Collaboration

We describe problems associated with accessing data resources external to the application, which we term externalities, in replicated synchronous collaborative applications (e.g., a multiuser text editor). Accessing externalities such as les, databases, network connections, environment variables and the system clock is not as straightforward in replicated collaborative software as in single-user applications and centralized collaborative systems. We describe ad hoc solutions that have been used previously. Our primary objection to the ad hoc solutions is that the developer must program dierent behavior into the dierent replicas of a multi-user application, which increases the cost and complexity of development. We introduce a novel general approach to accessing externalities uniformly in a replicated collaborative system. The approach uses a semi-replicated architecture where the actual externality resides at a single location and is accessed via replicated proxies. The proxies multiplex input to and output from the single instance of the externality. This approach facilitates the creation of replicated synchronous groupware in two ways: (1) developers use the same mechanisms as in traditional single-user applications (2) developers program all replicas to execute the same behavior. We describe a general design for proxied access to read{only, write{only and read{write externalities. We discuss the tradeos of this semi- replicated approach over full, literal replication and the class of applications to which this approach can be successfully applied. We also describe details of a prototype implementation of this approach within a replicated collaboration-transparency system, called Flexible JAMM (Java Applets Made Multi-user)

Nasal Outcomes of Presurgical Nasal Molding in Complete Unilateral Cleft Lip and Palate

Objective. Short-term nasal forms following primary lip repair were compared between presurgical nasal molding and control groups. Aim. To compare nasal symmetry between patients that had nasal molding and lip repair with those that had only lip repair. Design. Retrospective case-control study Patients. Complete unilateral CL+P patients had basilar and frontal photographs at two time points: (1) initial (2) postsurgical. 28 nasal molding patients and 14 control patients were included. Intervention. Presurgical nasal molding was performed prior to primary lip repair in intervention group. No nasal molding was performed in control group. Hypothesis. Nasal molding combined with lip surgery repair according to the Millard procedure provides superior nasal symmetry than surgery alone for nostril height-width ratios and alar groove ratios. Statistics. Shapiro-Wilk test of normality and Student’s -tests. Results. A statistically significant difference was found for postsurgical nostril height-width ratio (<.05). No other statistically significant differences were found. Conclusions. Nasal molding and surgery resulted in more symmetrical nostril height-width ratios than surgery alone. Alar groove ratios were not statistically significantly different between groups perhaps because application of nasal molding was not early enough; postsurgical nasal splints were not utilized; overcorrection was not performed for nasal molding

A practical activity capture framework for personal, lifetime user modeling

Abstract. This paper addresses the problem of capturing rich, longterm personal activity logs of users ’ interactions with their workstations, for the purpose of deriving predictive, personal user models. Our architecture addresses a number of practical problems with activity capture, including incorporating heterogeneous information from different applications, measuring phenomena with different rates of change, efficiently scheduling knowledge sources, incrementally evolving knowledge representations, and incorporating prior knowledge to combine low-level observations into interpretations better suited for user modeling tasks. We demonstrate that the computational and memory demands of general activity capture are well within reasonable limits even on today’s hardware and software platforms.