Vladimir Korolev

Agents2Go: an infrastructure for location-dependent service discovery in the mobile electronic commerce environment

In recent years, the growth of Electronic Commerce and Mobile Computing has created a new concept of Mobile Electronic Commerce. In this paper we describe the Agents2Go System that attempts to solve problems related to location dependence that arise in a Mobile Electronic Commerce environment. Agents2Go is a distributed system that provides mobile users with the ability to obtain location dependent services and information. Our system also automatically obtains a users current geographical location in CDPD (Cellular Digital Packet Data) based systems without relying on external aids such as GPS (Global Positioning System).

An end-end approach to wireless Web access

We propose a lightweight scheme for negotiating client capabilities in the context of end-end content adaptation for wireless Web access. Our method is much less complex then W3Cs proposed CC/PP framework. We suggest that for the purposes of content negotiation, all (mobile) clients could be grouped into a few relatively large categories. With this assumption, we simplify the CC/PP protocol and implement it as an Apache module. The paper describes the simple CC/PP protocol, issues related to its implementation, and performance measurements.

On experiments with a transport protocol for pervasive computing environments

It is well-known that TCP performs poorly in a wireless environment. This paper presents an empirical performance analysis of TCP on cellular digital packet data, Bluetooth and wireless LAN. We also present CentaurusComm, a message based transport protocol designed to perform well in low bandwidth networks and resource poor devices. In particular, CentaurusComm is optimized to handle data exchanges consisting of short message sizes. The application used to perform all the experiments is typical of common applications that would use these protocols and network technologies. Typical mobile devices used in the experiments included Palm Pilots. We present results of performance evaluation of TCP and CentaurusComm on different wireless technologies.

Transport protocols in wireless networks

It is well-known that TCP performs poorly in a wireless environment. This paper presents an empirical performance analysis of TCP on cellular digital packet data (CDPD) and Bluetooth, This analysis brings out the weaknesses of TCP in realistic conditions, We also present CentaurusComm, a message-based transport protocol designed to perform well in low-bandwidth networks and resource-poor devices. In particular, CentaurusComm is optimized to handle data exchanges consisting of short message sizes. The application used to perform all the experiments is typical of common applications that would use these protocols and network technologies, Typical mobile devices used in the experiments included Palm Pilots. We show that TCP performance on CDPD is very poor because of its low bandwidth and high latency. CentaurusComm outperforms TCP on CDPD. We show that on Bluetooth, which has higher bandwidth and lower latency than CDPD, both protocols perform comparably.