Vol. 27 · No. 6

The paper addresses the multiple forms of representation that human gesture takes at different levels for human computer interaction, ranging from gesture acquisition to mathematical model for analysis, pattern for recognition, record for database up to end-level application event triggers. A mathematical model for gesture as command is presented. We equally identify and provide particular models for four different types of gestures by considering both posture information and underlying motion trajectories. The problem of constructing gesture dictionaries is further addressed by taking into account similarity measures and dictionary discriminative features.

Tracking moving targets is one of the important problems of wireless sensor networks. We have considered a sensor network where numerous sensor nodes are spread in a grid like manner. These sensor nodes are capable of storing data and thus act as a separate datasets. The entire network of these sensors act as a set of distributed datasets. Each of these datasets has its local temporal dataset along with spatial data and the geographical coordinates of a given object or target. In this paper an algorithm is introduced that mines global temporal patterns from these datasets and results in the discovery of linear or nonlinear trajectories of moving objects under supervision. The main objective here is to perform in-network aggregation between the data contained in the various datasets to discover global spatio-temporal patterns; the main constraint is that there should be minimal communication among the participating nodes. We present the algorithm and analyze it in terms of the communication costs.

In this paper we propose analytic model for computing the delay of the slotted ALOHA protocol with Binary Exponential Backoff (BEB) with multiple priorities as a collision resolution algorithm in mobile information systems. If a packet which tries to reserve a channel collides times, it chooses one of the next 2n frames with equal probabilities and attempts the reservation again. We derive the expected access delay until an arbitrary packet reserves a channel in any cell. Then the expected transmission delays for packets of calls with multiple priorities are calculated analytically. Proposed analytic model is checked against simulation.

Augmented reality deals with the problem of dynamically augmenting or enhancing the real world with computer generated virtual scenes. Registration is one of the most pivotal problems currently limiting AR applications. In this paper, a novel registration method using natural features based on online estimation of trifocal tensors is proposed. This method consists of two stages: offline initialization and online registration. Initialization involves specifying four points in two reference images respectively to build the world coordinate system on which a virtual object will be augmented. In online registration, the natural feature correspondences detected from the reference views are tracked in the current frame to build the feature triples. Then these triples are used to estimate the corresponding trifocal tensors in the image sequence by which the four specified points are transferred to compute the registration matrix for augmentation. The estimated registration matrix will be used as an initial estimate for a nonlinear optimization method that minimizes the actual residual errors based on the Levenberg-Marquardt (LM) minimization method, thus making the results more robust and stable. This paper also proposes a robust method for estimating the trifocal tensors, where a modified RANSAC algorithm is used to remove outliers. Compared with standard RANSAC, our method can significantly reduce computation complexity, while overcoming the disturbance of mismatches. Some experiments have been carried out to demonstrate the validity of the proposed approach.

Benchmark circuits provide a basis for both research institutions and industry to measure their methods and products against. This paper focuses on utilization of recently published FITTest BENCH06 benchmarks for measuring quality of our novel academic design for testability tool called CADeT. The paper presents basic characteristics of benchmarks and CADeT tool, provides results and analysis of implementing individual testing techniques and their constraint-driven combination to particular benchmarks.

The importance of a security operating system (OS) with security-enhancing mechanisms at the kernel level, such as a reference monitor and a cryptographic file system, has been increasingly emphasized as the weaknesses and limitation of mechanisms at the user level have been revealed. However, when a system has only a reference monitor, the system is vulnerable to a low-level detour or a physical attack. In addition, when a system has only a cryptographic file system, the file system has a difficulty in protecting itself. To address these problems, we designed and developed a security OS with a reference monitor, a cryptographic file system, authentication limitation, and session limitation. Here we describe the model, its implementation, and its overheads.