MinHwan Ok

UbiqStor: a remote storage service for mobile devices

In Ubiquitous computing environment the mobile devices such as PDAs necessarily connect to remote storage servers. We present an iSCSI caching system that localizes iSCSI target to overcome the shortcomings of iSCSI performance dropping sharply as the latency increases.

A distributed resource furnishing to offload resource-constrained devices in cyber foraging toward pervasive computing

Mobile devices are pursuing the succession of desktop PCs these days. Cyber Foraging is the project that investigated overcoming scarce computing resources and reducing the power consumptions of mobile devices. In this paper, we propose a framework for remote execution of mobile devices in the way of delivering user data and invoking and manipulating the software of a surrogate with VNC-style interface. This resource furnishing system has the merits of remote application execution, and automatic file transfer. Remote execution is provided via VNC-style interface that is user-friendly. Performance evaluation shows the feasibility of the resource furnishing system, for both data transfers over wired and wireless network.

An intermediate target for quick-relay of remote storage to mobile devices

Requests for application services that require large data space such as multimedia, game and database[1] have greatly increased. Nowadays those requests locomote for various services using mobile devices. However, mobile devices have difficulty in sustaining various services as in a wired environment, due to the storage shortage of the mobile device. The research[5] which provides remote storage service for mobile appliances using iSCSI has been conducted to overcome the storage shortage in mobile appliances. In research we found that when iSCSI was applied to mobile appliances, iSCSI I/O performance dropped rapidly if a iSCSI client had moved from the server to a far away location. It occurred due to the specific character of iSCSI, which is very sensitive to delay time. In this paper, we suggest an intermediate target server that localizes iSCSI target to achieve a breakthrough against the shortcomings of iSCSI performance dropping sharply as latency increases when mobile appliances recede from a storage server.

UbiqStor: server and proxy for remote storage of mobile devices

Mobile devices have difficulty in sustaining various services as in a wired environment, due to the storage shortage of the mobile device. The research[8] which provides remote storage service for mobile appliances using iSCSI has been conducted to overcome the storage shortage in mobile appliances. In research the proposed cache server performed well with relatively small files of sizes, however, did not perform well with large files such as database files, multimedia files, etc. The reason was the mobile device could not grasp the file as a whole and thus the cache server encountered frequent cache miss in spite of its huge buffer. In this paper we propose a proxy server that accommodates large files for mobile devices thus attains very high hit ratio.

Request Distribution for Fairness with a New Load-Update Mechanism in Web Server Cluster

The complexity of services and applications provided by Web sites is ever increasing as integration of traditional Web publishing sites with new paradigms, i.e., e-commerce. Each dynamic Web page is difficult to estimate its execution load even with the information from the application layer. In this paper the execution latency at Web server is exploited in order to balance loads from dynamic Web pages. With only the information such as IP address and port number for Layer-4 Web switch the proposed algorithm balances the loads with a new load-update mechanism. The mechanism uses the report packets more efficiently with the same communication cost. Moreover the proposed algorithm considers the fairness for Web clients hence the Web clients would experience higher quality of service.

Minimizing hotspot delay by fully utilizing the link bandwidth on 2d mesh with virtual cut-through switching

The hotspot seriously degrades the performance of a parallel algorithm but there have not been many methods proposed for this problem. Without modification of mesh topology a reasonable method is fully utilizing all the links of the hotspot node. A new routing method that incorporates both minimal routes and non-minimal routes was proposed and approved with the hotspot traffic patterns. In particular the routing method decide on misrouting without the congestion detection. The routing method requires only little addition of hardware and it is relatively simple.

LVS Digital Library Cluster with Fair Memory Utilization

A digital library system consists of LVS(Linux Virtual Server) operating with software clustering technology provides is designed on Linux environment. In the cluster of servers fair load distribution scheme that exploits memory utilization was proposed on the assumption that it reflects each server’s load more effectively, and was simulated.

Agent-Based Fair Load Distribution in Linux Web Server Cluster

Clustering the replicated Web servers is appropriate way to build a Web information system. An LVS(Linux Virtual Server) operating with software clustering technology provides the Web service based on Linux environment. The LVS is the centralized structure, which the load should be distributed to the real servers by a load balancer. A round-robin scheduling method or a least-connection scheduling method may cause a load imbalance amongst the real servers since such methods distribute the load to the real servers without considering the actual load of real servers. In this paper, we propose a fair load distribution scheme that can distribute the requests even fair than ABSS that was early proposed to solve the problem of scheduling methods in the LVS.