Jaehyun Choi

A Comparative Study between Stock Price Prediction Models Using Sentiment Analysis and Machine Learning Based on SNS and News Articles

Submitted:July 14, 2014 1 Revision:September 12, 2014 Accepted:September 15, 2014 * 숭실대학교 SW특성화대학원 석사과정 ** 숭실대학교 SW특성화대학원 교수 *** 숭실대학교 SW특성화대학원 교수, 교신저자 Because peoples interest of the stock market has been increased with the development of economy, a lot of studies have been going to predict fluctuation of stock prices. Latterly many studies have been made using scientific and technological method among the various forecasting method, and also data using for study are becoming diverse. So, in this paper we propose stock prices prediction models using sentiment analysis and machine learning based on news articles and SNS data to improve the accuracy of prediction of stock prices. Stock prices prediction models that we propose are generated through the four-step process that contain data collection, sentiment dictionary construction, sentiment analysis, and machine learning. The data have been collected to target newspapers related to economy in the case of news article and to target twitter in the case of SNS data. Sentiment dictionary was built using news articles among the collected data, and we utilize it to process sentiment analysis. In machine learning phase, we generate prediction models using various techniques of classification and the data that was made through sentiment analysis. After generating prediction models, we conducted 10-fold cross-validation to measure the performance of they. The experimental result showed that accuracy is over 80% in a number of ways and F1 score is closer to 0.8. The result can be seen as significantly enhanced result compared with conventional researches utilizing opinion mining or data mining techniques. Keyword:Data Mining, Stock Price Prediction, Sentiment Analysis, SNS, Big Data, Machine Learning 韓國IT서비스學會誌 第13卷 第3號 2014年 9月, pp.221-233 222 Dongyoung Kim.Jeawon Park.Jaehyun Choi

A Technique of Statistical Message Filtering for Blocking Spam Message

Abstract Submitted：July 28, 2014 1 st Revision：September 17, 2014 Accepted：September 22, 2014* 숭실대학교 SW특성화대학원 석사과정** 숭실대학교 SW특성화대학원 교수*** 숭실대학교 SW특성화대학원 교수, 교신저자Due to indiscriminately received spam messages on information society, spam messages cause damages not only to person but also to our community. Nowadays a lot of spam fil tering techniques, such as blocking characters, are studied actively. Most of these studies are content-based spam filtering technologies through machine learning.. Because of a spam message transmission techniques are being dev eloped, spammers have to send spam messages using term spamming techniques. Spam messages tend to include n umber of nouns, using repeated words and inserting special characters between words in a sentence. In this paper, considering three features, SPSS statistical program were used in parameterization and we derive the equation. And t hen, based on this equation we measured the performance of classification of spam messages. The study compa red with previous studies FP-rate in terms of further minimizing the cost of product was confirmed to show an excelle nt performance.

A Framework for Remote Service Invocation of Android Services to Communicate with External Services in Java Environment

Recently, smart phones have been widely used in the world. Android phones especially provide existing mobile phone features as well as capability of running enterprise applications and web applications by using services. However, such a linkage has limitations to use Android phones as client devices, there is difficulties in providing services by utilizing characteristics of Android. To solve this problem, we need to invoke services by each other. Currently, the Android platform currently supports inter-process communication IPC. However, there is a limitation that Android services just can invoke remote calls. In this paper, we propose a framework to invoke Android services in java environments. For doing this, we propose methods to make services public and to invoke services in using remote calls and communication methods between java environments and Android.