Shervin Shirmohammadi

A survey of application-layer multicast protocols

In light of the slow deployment of IP Multicast technology on the global Internet and the explosive popularity of peer-to-peer (P2P) file-sharing applications, there has been a flurry of research activities investigating the feasibility of implementing multicasting capability at the application layer, referred to as Application Layer Multicasting (ALM), and numerous algorithms and protocols have been proposed. This article aims to provide researchers in the field with an understanding of ALM protocols by identifying significant characteristics, from both application requirements and networking points of view, and by using those characteristics as a basis for organizing the protocols into an integrated and well-structured format. Current trends and directions for further research are also presented. This article surveys the literature over the period 1995¿2005 on different application layer multicasting approaches.

An end-to-end communication architecture for collaborative virtual environments

Abstract Synchronous collaboration in virtual reality spaces has specific requirements that differ from those of other application data, leading to a different communication approach. Update messages corresponding to the change in the state of a shared object must be communicated both reliably and in a timely manner among users. While a lot of research has been done in terms of transmission of update messages representing the motion of avatars and objects, very few works focus on collaboration itself. Here, we present an architecture that supports tightly coupled collaborative tasks to be performed efficiently in virtual environments. The architecture consists of an application-general layer which is mapped into a communication protocol. An implementation is also presented as proof of concept.

An RFID-Based Position and Orientation Measurement System for Mobile Objects in Intelligent Environments

Ambient intelligence (AmI) considers responsive environments in which applications and services adapt their behavior according to the users needs and changing context. One of the most challenging aspects for many applications in AmI environments is location and orientation of the surrounding objects. This is especially important for effective cooperation among mobile physical objects in such smart environments. In this paper, we propose a robust indoor positioning system that provides 2-D positioning and orientation information for mobile objects. The system utilizes low-range passive radio frequency identification (RFID) technology. The proposed system, which consists of RFID carpets and several peripherals for sensor data interpretation, is implemented and tested through extensive experiments. Our results show that the proposed system outperforms similar existing systems in minimizing the average positioning error.

Camera as the instrument: the rising trend of vision based measurement

In this article we gave an overview of vision-based measurement (VBM), its various components, and uncertainty in the correct IM (instrumentation and measurement) metrological perspective. VBM is a fast rising technology due to the increasing affordability and capability of camera and computing hardware/software. While originally a specialized application, VBM is expected to become more ubiquitous in our everyday lives as apparent from the applications described in this article.

Measuring Calorie and Nutrition From Food Image

As people across the globe are becoming more interested in watching their weight, eating more healthy, and avoiding obesity, a system that can measure calories and nutrition in every day meals can be very useful. In this paper, we propose a food calorie and nutrition measurement system that can help patients and dietitians to measure and manage daily food intake. Our system is built on food image processing and uses nutritional fact tables. Recently, there has been an increase in the usage of personal mobile technology such as smartphones or tablets, which users carry with them practically all the time. Via a special calibration technique, our system uses the built-in camera of such mobile devices and records a photo of the food before and after eating it to measure the consumption of calorie and nutrient components. Our results show that the accuracy of our system is acceptable and it will greatly improve and facilitate current manual calorie measurement techniques.

Applet-based telecollaboration: a network-centric approach

Real-time collaboration systems, in which participants share multimedia documents and applications, have attracted interest for many years. The JETS system provides a generic multimedia telecollaboration framework that enables sharing of Java applets through the Internet. Experimentation with JETS revealed practical design and implementation issues, as well as the essential requirements of such systems.

Equipment Location in Hospitals Using RFID-Based Positioning System

Throughout various complex processes within hospitals, context-aware services and applications can help to improve the quality of care and reduce costs. For example, sensors and radio frequency identification (RFID) technologies for e-health have been deployed to improve the flow of material, equipment, personal, and patient. Bed tracking, patient monitoring, real-time logistic analysis, and critical equipment tracking are famous applications of real-time location systems (RTLS) in hospitals. In fact, existing case studies show that RTLS can improve service quality and safety, and optimize emergency management and time critical processes. In this paper, we propose a robust system for position and orientation determination of equipment. Our system utilizes passive (RFID) technology mounted on flooring plates and several peripherals for sensor data interpretation. The system is implemented and tested through extensive experiments. The results show that our systems average positioning and orientation measurement outperforms existing systems in terms of accuracy. The details of the system as well as the experimental results are presented in this paper.

Haptic Virtual Rehabilitation Exercises for Poststroke Diagnosis

Nowadays, stroke is one of the most frequent causes of severe adult disability in the world. Virtual reality and haptic technologies have emerged as promising assistive tools for effective diagnosis and rehabilitation intervention. The objective of this paper is to develop and test a set of five virtual exercises on top of a framework, which is designed for the diagnosis and rehabilitation of patients with hand impairments. We have implemented task-oriented exercises based on well-established and common exercises, namely the Jebsen Test of Hand Function and the Box and Block Test. These include moving a cup, arranging blocks, navigating a maze, training with a dumbbell, and grasping a rubber ball. Furthermore, key performance measures (metrics) are proposed for each exercise to quantitatively evaluate and judge the performance of stroke patients. Our evaluation of these exercises shows promising potential to define ldquogoldenrdquo reference metrics for healthy subjects, against which the performance of a patient is compared. This will facilitate the ability of occupational therapists to assess the patients progress.

A Novel Biometric System for Identification and Verification of Haptic Users

Currently, almost all systems involve an identity authentication process before a user can access requested services such as online transactions, entrance to a secured vault, logging into a computer system, accessing laptops, secure access to buildings, etc. Therefore, authentication has become the core of any secure system, wherein most of the cases rely on identity recognition approaches. Biometric systems provide the solution to ensure that the rendered services are accessed only by a legitimate user and no one else. Biometric systems identify users based on behavioral or physiological characteristics. The advantages of such systems over traditional authentication methods, such as passwords and IDs, are well known; hence, biometric systems are gradually gaining ground in terms of usage. We investigate the issues related to the usage of haptics as a mechanism to extract behavioral features that define a biometric identifier system. In order to test this possibility, we design a haptic system in which position, velocity, force, and torque data from the instrument is continuously measured and stored as users perform a specific task. We analyze the information content of the haptic data generated directly from the instruments interface. We then measure the physical attributes such as force and torque that provide the richest information content pertaining to a users identity. Through a series of experimental work, we discover that haptic interfaces are more suited to verification mode rather than identification mode. Finally, we implement a biometric system based on haptics

A Visibility-Driven Approach to Managing Interest in Distributed Simulations with Dynamic Load Balancing

Distributed simulations that support a massive number of users typically divide the virtual world into zones that are managed by separate servers to evenly distribute resources and achieve scalability. However, such zoning restricts cross-zonal interactions and exposes the division of the world to the participating parties. Problems such as crowding one zone among others defeats the very purpose of interest management and makes geographic partitioning inefficient for modeling interactions. In this work, we have designed and implemented a visibility-driven approach to make the partitioning transparent to users. The effectiveness of this distributed architecture is tested through a prototype implementation. We also introduce a novel idea to dynamic load balancing that can be achieved in real-time without modifying the communication architecture. By increasing the granularity of the partitioning and providing a layered approach to zoning, transient crowding can be handled by adoptively dispersing parts of the crowded zone to adjacent servers.