HwaMin Lee

Proxy based seamless connection management method in mobile cloud computing

Nowadays, complex smartphone applications are developed that support gaming, navigation, video editing, augmented reality, and speech recognition which require considerable computational power and battery lifetime. The cloud computing provides a brand new opportunity for the development of mobile applications. Mobile Hosts (MHs) are provided with data storage and processing services on a cloud computing platform rather than on the MHs. To provide seamless connection and reliable cloud service, we are focused on communication. When the connection to cloud server is increased explosively, each MH connection quality has to be declined. It causes several problems: network delay, retransmission, and so on. In this paper, we propose proxy based architecture to improve link performance for each MH in mobile cloud computing. By proposed proxy, the MH need not keep connection of the cloud server because it just connected one of proxy in the same subnet. And we propose the optimal access network discovery algorithm to optimize bandwidth usage. When the MH changes its point of attachment, proposed discovery algorithm helps to connect the optimal access network for cloud service. By experiment result and analysis, the proposed connection management method has better performance than the 802.11 access method.

A Resource Management System for Fault Tolerance in Grid Computing

In Grid computing, resource management and fault tolerance services are important issues. The availability of the selected resources for job execution is a primary factor that determines the computing performance. The failure occurrence of resources in the grid computing is higher than in a tradition parallel computing. Since the failure of resources affects job execution fatally, fault tolerance service is essential in computational grids. And grid services are often expected to meet some minimum levels of quality of service (QoS) for desirable operation. However Globus toolkit does not provide fault tolerance service that supports fault detection service and management service and satisfies QoS requirement. Thus this paper proposes fault tolerance service to satisfy QoS requirement in computational grids. In order to provide fault tolerance service and satisfy QoS requirements, we expand the definition of failure, such as process failure, processor failure, and network failure. And we propose resource scheduling service, fault detection service and fault management service and show implement and experiment results.

An instant messenger system for learner analysis in e-learning environment

In this paper, we present the idea of using an instant messenger system to collect and analysis information of learner in e-learning environment. For learner behavior analysis, we store data about the learners actions in log files by information gathering agent and perform basic analysis, process analysis and synthesis analysis by information analysis agent. Our instant messenger system can provide personalized feedback to learners about the quantity of quality of their learning.

An efficient distributed mutual exclusion algorithm for intersection traffic control

As vehicular networking has recently been developed and commercialized, vehicular cloud computing has received much attention in various research areas, such as intelligent transportation systems and vehicular ad hoc networks. An efficient intersection traffic control using vehicular cloud computing is one of the key research topics in intelligent transportation systems. To efficiently deal with intersection traffic control via vehicle-to-vehicle communications, we design a distributed mutual exclusion algorithm that does not rely on broadcast, which introduces communication overheads; instead, our algorithm use point-to-point messages sent between the vehicles to keep network traffic load lower. In our algorithmic design, to pass an intersection, the lead vehicle on a lane must get permissions from a subset of other vehicles and its following vehicles on the same lane can follow the lead vehicle without permissions unlike the previous research. To evaluate the performance of our distributed mutual exclusion algorithm, we conduct extensive experiments. The results show that our algorithmic design is both effective and efficient.

Replication and Checkpoint Schemes for Task-Fault Tolerance in Campus-Wide Mobile Grid *

Mobile grid computing is a computing environment that incorporates mobile devices to an existing grid environment and supports users’ mobility. But this environment is not stable, so methodologies to cope with the reliability issue are needed. Fault tolerance approaches for task execution in grid computing can be categorized into replication and checkpoint. We apply these techniques to a SimGrid simulator to provide a fault tolerance for a mobile environment and show the results in this paper. The results demonstrate that the best solution for fault tolerance in mobile grid computing depends on the situations of the network. The contribution of this paper is the use of real-life trace data to simulate fault tolerance in a mobile grid computing.

A low cost wearable wireless sensing system for paretic hand management after stroke

This paper describes the design of a low cost wearable hand exercise device that can assist repetitive wrist and finger exercise for stroke patients. The design of this device was guided by neurobiological principles of motor learning, such as sensory-motor integration, movement repetition, and cognitive interaction. This pilot study tested the efficacy of a wireless sensing system in the device to serve as a facilitator of repetitive hand exercise, which is an essential part of rehabilitation after stroke. The results from healthy young adults showed that the device with a wireless sensing system yielded quantitatively better motor function with the repetitive wrist and finger joint movements.This proof-of-concept study shows potential therapeutic evidence for stroke rehabilitation as well as the potential utility of sensing system for stroke rehabilitation.

Personalized Movie Recommendation System Using Context-Aware Collaborative Filtering Technique

ABSTRACT The explosive growth of information has been difficult for user s to get an appropriate information in time. The various ways of new services to solve problems has been provided. As customized service is being magnified, the personalized recommendation sy stem has been important issue. Collaborative filtering system in the recommendation system is widely used, and it is the most successful process in the recommendation system. As the recommendation is based on customers’ profile, there can be sparsity and cold-start problems. In this paper, we propose personalized movie recommen dation system using collaborative filtering techniques and context-based techniques. The context-based technique is the re commendation method that considers user’s environment in term of time, emotion and location, and it can reflect user’s preferences depending on the various environments. In order to utilize the context-based technique, this paper uses the human emotion, and uses movie reviews which are effective way to identify subject ive individual information. In this paper, this proposed method shows outperforming existing collaborative filtering methods.

The Idle Mobile Resource Discovery and Management Scheme in Mobile Grid Computing Using IP-paging

In this paper, we tried to enable a mobile device as a resource to access to the grid network. By improved internet technique, the use of mobile devices is rapidly increased. And some researches in grid computing tried to combine grid computing with mobile devices. However, according to properties of mobile environments, mobile devices have many considerations, such as mobility management, disconnected operation, device heterogeneity, service discovery, resource sharing, security and so on. To conquest these problems, there are two trends for mobile grid computing: a proxy-based mobile grid architecture and an agent-based mobile grid architecture. We focused on a proxy-based mobile grid architecture with IP-paging, which easily manage idle mobile devices and grid resource status information. In result, to support mobile grid services, we propose the IP-paging scheme based on the mobile grid computing framework. Moreover, we have discussed some research issues: location tracking using IP-paging, limited power using grid paging cache, and service migration using reserved resource. And, we also propose a mobile proxy and paging agent prototype. Keywords-component; Mobile Grid Computing, IP-Paging, Active/Idle state, Power consumption

Identifying the social-balanced densest subgraph from signed social networks

Identifying the dense subgraphs from large graphs is important and useful to various social media mining applications. Most of existing works focus on the densest subgraph problem in the unweighted and undirected represented social network which can maximize the average degree over all possible subgraphs. However, considering the frequent signed relationships occurred in real-life social network, this paper introduces the social-balanced densest subgraph problem in signed social network by incorporating the social balance theory. We obtain a novel problem formulation that is to identify the subset of vertices that can maximize the social-balanced density in signed social networks. Further, we propose an efficient approach for identifying the social-balanced densest subgraph based on formal concept analysis. The case study illustrates that our algorithm can efficiently identify the social-balanced densest subgraph for satisfying the specific application’s requirements.

A Grid Service-Based Virtual Screening System

Virtual screening is the process of reducing an unmanageable number of compounds to a limited number of compounds by means of docking. It is one of the large-scale scientific applications that require large computing power and data storage capability. Grid computing focuses on large-scale resource sharing, innovative applications and high-performance orientation. Thus we propose a service-based virtual screening system using Grid technology that supports a large computed and data-intensive operation. We constructed a three-dimensional chemical database and defined various services for virtual screening using XML and WSDL. And, we implemented a Grid service-based virtual screening system using DOCK 6.0.