Yong-Hoon Choi

Spatio-temporal mining for power load forecasting in GIS-AMR load analysis model

A spatio-temporal mining technique is used to predict power load patterns for a voltage transformer. It is applied from load data measured every thirty minutes and a GIS-AMR database collected by a transformers load measurement system over a wireless network. The proposed approach in this paper consists of three stages, (i) data preprocessing: noise or outlier is removed and the continuous attribute-valued features are transformed to new features (feature extraction and discretization), (ii) cluster analysis: SOMs (Self Organizing Maps) clustering is used to label the class and (iii) classification: we used and evaluated classification rules using spatio-temporal mining to build a suitable load forecasting model. In order to evaluate the result of classification, derived class labels from clustering and other features are used as input to build classification rules including time and spatial factors. Lastly, the result of our experiments is presented.

A Smart DTMC-based Handover Scheme Using Vehicle's Mobility Behavior Profile

For improvement of wireless Internet service quality at vehicles moving speed, it is advised to reduce the service disruption time by reducing the handover frequency on vehicles moving path. Particularly, it is advantageous to avoid the handover to cell whose dwell time is short or can be ignored in terms of service continuity and average throughput. This paper proposes the handover scheme that is suitable for vehicle in order to improve the wireless Internet service quality. In the proposed scheme, the handover process continues to be learned before being modeled to Discrete-Time Markov Chain (DTMC). This modeling reduces the handover frequency by preventing the handover to cell that could provide service sufficiently to passenger even when vehicle passed through the cell but there was no need to perform handover. In order to verify the proposed scheme, we observed the average number of handovers, the average RSSI and the average throughput on various moving paths that vehicle moved in the given urban environment. The experiment results confirmed that the proposed scheme was able to provide the improved wireless Internet service to vehicle that moved to some degree of consistency.