Tangible Augmented Reality (AR) enhances user immersion in virtual world by providing haptic feedback through physical proxy objects. However, existing approaches primarily focus on selecting proxy objects based on their global physical properties, neglecting the utilization of local features. Besides, the prevailing strategy of mapping one virtual object to a single dedicated physical proxy creates an inherent switching cost, limiting flexibility and efficiency. Additionally, due to challenges such as real-time performance, generalization and occlusion, the vision-based hand-object tracking remains a difficult task. In this paper, we propose Ubi Grip, an universal hand-object interaction framework for creating grip-based tangible AR applications based on the local graspable feature and a comprehensive hand-object interaction attributes methodology. We employ a lightweight object tracking method to perform tracking, utilizing a hand mask filter and transformation strategy to optimize object pose based on the hand-held properties. Moreover, we design a user-defined workflow for grasping tangible objects, allowing users to switch grips and map interactions. We evaluated our system through comprehensive algorithmic benchmarks and a user study. The benchmarks demonstrate our SOTA performance in object pose estimation and generalization, while the user study validates system usability, providing deeper insights.

Whiteboard collaboration in virtual reality (VR) is an important task in collaborative virtual environments. The current research mainly relies on the use of controllers or dedicated pens but additional devices will cause inconvenience to users. Bare-hand writing offers rich collaborative semantics through natural gestures but remains underexplored. This paper addresses challenges and solutions for bare-hand whiteboard collaboration. We analyze the input process and identify key challenges in determining pen-drop, writing, and pen-lift intentions while maintaining user control over their avatar. Our approach addresses two VR scenarios: one without and one with physical planes. The method for the first case is called Air-writing, which dynamically adjusts the distance between the avatar's torso and the virtual whiteboard during the processes of pen-drop and pen-lift to ensure a consistent writing experience in VR. The method for the second case is called Physical-writing, which allows users to write smoothly with passive haptic feedback and physical constraints provided by the real surface by remapping the whiteboard in VR with a plane in reality. A comprehensive user study is conducted to evaluate communication efficiency, input accuracy, collaboration efficiency, and user experience of the two methods. The experimental results indicate that bare-hand interaction improves communication efficiency by 8% over controllers and performs similarly to real-world whiteboard collaboration. The Physical-writing method also demonstrates higher accuracy and user satisfaction compared to the Air-writing method.

In the field of 360-degree video streaming, the optimization of visual quality within the viewer's field of view, alongside the minimization of system resource consumption, is a critical concern. The considerable file sizes associated with high-quality 360-degree videos pose significant challenges for efficient transmission. Current strategies primarily employ a tile-based approach to address these issues. However, these approaches face two core challenges: the methodology for tile segmentation, and the strategy for downloading tiles. To address these challenges, this paper presents a tile-based solution designed specifically for adaptive 360-degree video-on-demand streaming. Our method surpasses baseline methods in extensive simulations, positioning it as one of the leading solutions in the MMSys'24 Grand Challenge1.

Increasingly, business applications need to capture consumers' complex preferences interactively and monitor those preferences by translating them into event-condition-action (ECA) rules and syntactically correct processing specification. An expressive event model to specify primitive and composite events that may involve timing constraints among events is critical to such applications. Relying on the work done in active databases and real-time systems, this research proposes a new composite event model based on real-time logic (RTL). The proposed event model does not require fixed event consumption policies and allows the users to represent the exact correlation of event instances in defining composite events. It also supports a wide-range of domain-specific temporal events and constraints, such as future events, time-constrained events, and relative events. This event model is validated within an electronic brokerage architecture that unbundles the required functionalities into three separable components - business rule manager, ECA rule manager, and event monitor - with well-defined interfaces. A proof-of-concept prototype was implemented in the Java programming language to demonstrate the expressiveness of the event model and the feasibility of the architecture. The performance of the composite event monitor was evaluated by varying the number of rules, event arrival rates, and type of composite events.

Timeliness is an important attribute for e-brokerage both in the detection of opportunities in a narrow time window and also in facilitating differentiation of end-to-end quality of service (QoS). In this paper, we demonstrate how real-time event monitoring techniques can be applied to time-critical e-brokerage. We start with a formal timed event model which provides the semantics for specifying complex timing correlation rules in composite events. The formal event model of the system is based on RTL (Real Time Logic), which is important for disambiguating informal specifications when multiple instances of the same event type may appear in a timing correlation rule involving composite events. This leads to our design of an e-brokerage, online stock monitoring and alerting system which enables users to express their complex preferences and provides an alert service to users in a timely manner. The user's preferences are monitored by a real-time event monitor. We report the design of this system and some performance data characterizing some key timing parameters. Our system is being used by a class of MBA students in a field test.

With the increasing complexity of enterprise networks and the Internet, event correlation is playing an increasingly important role in network as well as integrated system management systems. Even though the timing of events often reveals important diagnostic information about event relationships and should therefore be represented in event correlation rules or models, most extant approaches lack a formal mechanism to define complex temporal relationships among correlated events. In this paper, we discuss the formal use of composite events for event correlation and present a composite event specification approach that can precisely express complex timing constraints among correlated event instances, for which efficient compilation and detection algorithms have been developed in Mok et al., (1997). A Java implementation of this approach, called Java Event Correlator (JECTOR), is described, and some preliminary experimental results of using JECTOR in an experimental network management environment are also discussed in the paper.

As real time applications become more complex and distributed, monitoring for timing constraint compliance becomes more important in facilitating the enforcement of conditional guarantees and for recovery purposes. C.E. Chodrow et al. (1991) described a O(n/sup 3/) satisfiability checking algorithm for timing constraint monitoring at each check point, where n is the number of time terms in the timing constraint specification. We show that a timing violation can be caught as early as possible by deriving and monitoring a minimum set of timing constraints from the timing constraint specification. We show that only O(n) time is needed in the worst case for checking at each check point. An implementation based on the results reported herein appears in a companion paper (A.K. Mok and G. Liu, 1997).