12678817
Developing a multifunctional network laboratory for teaching and research
Adequate hands-on experience on networking and computing is becoming vital and necessary for students majored in programs such as Information Technology and Computer Science. However, building a hands-on experimental lab environment turns out to be challenging for many institutions, particularly for a new-born program or an urban university, due to space constraints, budget limitations, maintenance difficulty and so on. This paper presents and explores the design of a multifunctional lab environment for both teaching and research while taking the cost and space challenges into consideration. On one hand, the lab utilizes a number of industrial-strength Cisco routers, switches and wireless access points to setup a practical platform that allows students to configure and administrate their network design by applying the knowledge learned in the classroom. On the other hand, the lab is equipped with useful (and mostly free) software packages such as OPNET, Network Simulator (NS-2), Virtual PC, and CPLEX, which enable students to conduct various network modeling, simulation, optimization, and emulation together with their research projects. Accordingly, each iteration for the lab design and implementation as well as experiences learned and future integration with additional curriculum, are presented in this paper.
20747570
An Energy-efficient Disjoint Path Routing Approach for Wireless Ad-hoc Networks
Apparatus and method are provided for assessing the direction of fixation of an eye by detecting polarization-related changes in light retroreflected from the fundus of the eye. Nerve fibers in the retina of the eye are birefringent and alter the polarization state of light traversing them as a function of their orientation. The nerve fibers are arrayed in a characteristic pattern in the retina, specifically radiating outward from the fovea and converging to the optic nerve head. By assessment of polarization-related changes in rctroreflected light from multiple retinal areas either sequentially or simultaneously, characteristic birefringence signatures of portions of the retina can be identified which are used to assess the direction of fixation of the eye. In addition, interference from the corneal birefringence is reduced by using incident light having a polarization state that is substantially independent of meridional direction. Circularly polarized light or non-polarized light is used for the assessment. Interference from the corneal birefringence is reduced still further by detecting polarization-related changes that are substantially independent of the meridional direction of the corneal birefringence. This is accomplished by detecting changes in ellipticity by measuring solely the Stokes parameter S3 or by measuring any two Stokes parameters. An alternative is measuring the overall intensity of the retroreflected light when the dichroism of the lutein pigment particles in the vicinity of the fovea is used for the assessment.
35951417
Tree-based Burst Aggregation in Optical Burst Switching Networks
The invention is a surface light source device capable of effectively producing polarized illumination light. The output angle of a representative beam C3 representing P-polarized component of output light from an emission surface 5 of the light guide plate 1 is about 75 DEG . Where P-polarization component of representative beam C3 is 100 (reference value), and the S-polarized component is 42.2. Representative beam C3 enters from an air layer AR to a flat surface 24g of a prism sheet 24, and then goes into the inside of prism sheet 24. At this stage the P-polarization component is 89.3 whereas the S-polarization component is 25.5. Beam C3 is incident on a slant surface 24d from its inside at an angle proximating the normal, and propagates into air layer AR between prism sheets 24, 34. Beam C3 impinges on a flat surface 34g of a prism sheet 34 while its corresponding part passes through the inside of prism sheet 34. At this stage its P-polarization component is 83.9 and its S-polarization component is 22.3. Beam C3 enters from the inside of one slope 34d of the prism array at the angle of incidence of 31 DEG . Its greater part is output to external air layer AR as illumination light substantially in the front direction.
41505059
Distributed Computation in Local Area Networks of Workstations
This paper describes the performance analysis of the local area network (LAN) of workstations for distributed computing applications. Several application programs represented in a task graph format are scheduled by the user workstation (master) for parallel execution in the idle or lightly loaded processors (slaves) in LAN. The partial results are collected by the master station to synchronize the operation of slave nodes. The system performance is characterized by the network speedup considering scheduling time, network load and size, communication time, TCP/IP communication overhead, task execution, and synchronization time. The sequential and parallel execution times and the performance degradation factors were measured during the implementation for various network loads. The measurement values and theoretical results have shown that the system performance is degraded mostly by the TCP/IP overhead (0.2 s), the network size, and the network load.
23887431
Generative and Discriminative Learning by CL-Net
This correspondence presents a two-stage classification learning algorithm. The first stage approximates the class-conditional distribution of a discrete space using a separate mixture model, and the second stage investigates the class posterior probabilities by training a network. The first stage explores the generative information that is inherent in each class by using the Chow-Liu (CL) method, which approximates high-dimensional probability with a tree structure, namely, a dependence tree, whereas the second stage concentrates on discriminative learning to distinguish between classes. The resulting learning algorithm integrates the advantages of both generative learning and discriminative learning. Because it uses CL dependence-tree estimation, we call our algorithm CL-Net. Empirical tests indicate that the proposed learning algorithm makes significant improvements when compared with the related classifiers that are constructed by either generative learning or discriminative learning.
42404496
A VRML interface for a knowledge-based structural design system
A variety of computer technologies have been applied to the field of civil engineering today. Visualization of structural design results focuses on geometry, modeling and simulation, ranging from static 2D images to dynamic 3D graphics. In recent years, advancements in multimedia, virtual reality and the Internet have given new prospects to visual aids for structural design. This paper presents the initial results of modeling steel structures in a virtual reality environment for interactive design examination and evaluation. Structural building designs are generated by a knowledge-based design system and converted to VRML models automatically, which allows 3D steel frames to be observed in Web browsers. Geometry and connective relations can be examined in arbitrary directions while the user walks through a scene, and detailed structural analysis and design results can be queried by touching the structural elements.
1683130
PLA-based runtime dynamism in support of privacy-enhanced Web personalization
Software product line architectures (PLAs) have been widely recognized as a successful approach in industrial software development for improving productivity, software quality and time-to-market. In this paper, we focus on the usage of a PLA for a quite different purpose, namely, handling privacy constraints in Web personalization. To provide personalized services such as customized recommendations, a personalized Website collects users' personal data, which raises various privacy concerns. We aim at reconciling the benefits of web personalization with privacy constraints that come from users themselves as well as from privacy legislations and regulations that apply to a given user. We propose a dynamic, privacy-enabling personalization infrastructure and conceive it as a PLA. This infrastructure allows for dynamically selecting and instantiating personalization architectures that provide personalized services to each individual user and comply with the prevailing privacy constraints
5609348
Non-blocking message total ordering protocol
Message total ordering is a critical part in active replication in order to maintain consistency among members in a fault tolerant group. The paper proposes a non-blocking message total ordering protocol (NBTOP) for distributed systems. Non-blocking property refers to that the members in a fault tolerant group keep on running independently without waiting for installing the same group view when a fault tolerant group evolves even when decision messages collide. NBTOP takes advantage of token ring as its logical control way. Members adopt re-requesting mechanism (RR) to obtain their lost decisions. Forward acknowledgement mechanism (FA) is put forth to solve decision collisions. The paper further proves that NBTOP satisfies the properties of total order, agreement, and termination. NBTOP is implemented, and its performance test is done. Comparing with the performance of Totem, the results show that NBTOP has a better total ordering delay. It manifests that non-blocking property helps to improve protocol efficiency.