10387460
Understanding current IPv6 performance: a measurement study
Much work has been done on IPv6 standards and testbeds deployment. However, little is known about the performance of the real IPv6 Internet, especially from the perspective of end users. In this paper, we present a measurement study of current IPv6 performance conducted from CERNET. We study 585, 680 packet-level traces with 133,340 million packets collected from 936 IPv4/IPv6 dual-stack Web servers located in 44 countries. We present a comprehensive performance comparison of IPv6 and IPv4, including connectivity, packet loss rate, round-trip time, etc. Our measurement results show that IPv6 connections tend to have smaller RTTs than their IPv4 counterparts, but suffer higher packet loss rate at the same time. We also notice that tunneled paths do not show notable performance degradation compared with native paths. To our best knowledge, this paper is the first performance study based on both large scale TCP and ICMP traffic measurement in real IPv6 Internet.
215142
A Study of Internet Packet Reordering
Packet reordering is a well-known phenomenon that the order of packets is inverted in the Internet. Previous studies indicates reordering can affect the performance of both the network and the packets receiver. Nevertheless, they get different results about the prevalence of reordering in the Internet. In this paper, we firstly present a methodology for single-point reordering measurement at a TCP receiver, including the algorithm and its implementation. Then we show the results of our three-week observation of reordering from a set of 10,647 Internet Web sites in China. In addition, we discuss a method to distinguish reordering and loss by making use of the distribution of their time lag and packet lag. Finally, we study the pertinence of sites experiencing reordering according to the network topology and propose a novel and relatively reliable approach to infer reorder-generating spots in the Internet.
2059756
Design of a Cognitive Complexities Measurement and Analysis Tool
The complexities of software systems are more prominent now than ever, due to progression of simple software applications to large integrated systems, either centralized or distributed. The challenges to software engineer somehow to understand and manage such large software systems and deal with software cognitive complexities. Although there are research areas such as human machine interface or human factor engineering, there is still little research on how to quantitatively measure and analyze human cognitive complexities in comprehending and understanding complex software systems. This paper studies human interaction with software programs in the cognitive perspective on software complexity. Based on the findings, a pilot software cognitive complexity measurement and analyses tool (CCMAT) is presented
14708720
Coding of faded scene transitions
Coding of a scene transition is often a challenging problem, from the compression efficiency point of view, because motion compensation may not be a powerful enough method to represent changes between pictures in the transition. This paper proposes a overlay coding technique for coding faded scene transitions. As shown by extensive simulations, over 50% bit-rate savings in both cross-fades and through-black fades compared to earlier techniques can be achieved. Overlay coding suits situations where video is edited manually or automatically.
18364887
An approach to enhancing mobile applications with situation-awareness capabilities
In ubiquitous computing environments, mobile applications reside in devices that move arbitrarily and communicate with each other through wireless means. They are presented with fast changing situations, such as the location variation, service availability change, and resource fluctuation. Under these circumstances, situation-awareness is a desirable feature for mobile applications. Being situation-aware, a mobile application is capable of detecting situation changes and responding to it on-the-fly without bothering the user all the times. This paper presents an approach to enhancing mobile applications with situation-aware capabilities using middleware service.
7119224
A new scheme on link quality prediction and its applications to metric-based routing
Efficient routing in wireless sensor networks entails the establishment of high quality links. Recent research has shown that metric-based routing, such as ETX [6]can significantly improve routing performance by tracking various link-quality metrics. Such metrics, however, may fail to capture link quality at relatively high traffic rates. This poster describes how machine learning techniques can be leveraged to help estimate link quality in those adverse scenarios. We also present MetricMap, a metric-based protocol using our learning-enabled link quality assessment method. Experimental results on MoteLab show that MetricMap can achieve up to 400% improvement on data delivery rate in a high traffic rate application, with no negative impact on other performance metrics, such as data latency.
6216289
Efficient and Secure Storage Systems Based on Peer-to-Peer Systems
Two fundamental problems that confront peer-to-peer applications are to efficiently locate the node that stores a data object and to achieve data security (e.g., confidentiality, integrity, authentication, and authorization). This paper presents a model for secure distributed applications based on peer-to-peer systems and presents Chord , a distributed lookup protocol that address the data object location problem in peer-to-peer systems. The protocol Chord is a novel combination of Chord and Tapestry/Plaxton-Rajaraman-Richa with provable better performance. In particular, node insertion in our scheme could be finished in steps (all other existing node insertion algorithms for peer-to-peer systems take steps—see the summary in Hildrum et al.).