Dear colleagues and researchers,
The Journal of the Korean Society for Industrial and Applied Mathematics (JKSIAM) Volume 26 Number 1 (March 2022 issue) has been posed on KSIAM Journal Archive or other information on the journal is available on the KSIAM website http://www.ksiam.org or https://ksiam.org/journal/journal01.asp.
The journal is one of Korea Citation Indexed (KCI) journals since 2007 and is indexed in Emerging Sources Citation Index (ESCI) since 2017.
Readers interested in the following articles may download each of articles free of charge from our website and authors are encouraged to submit a paper via the online submission site.
Sincerely yours,
Jae Hoon Jung, EditorinChief
Zhiming Chen, HyeongOhk Bae, Tao Tang, Associate EditorsInChief
Min Seok Choi, Gun Jin Yun, Managing Editors
JKSIAMv26n1 pp122
AN APPROXIMATE ANALYSIS OF TANDEM QUEUES WITH GENERAL BLOCKING NODES
YANG WOO SHIN, DONG OK KIM, AND DUG HEE MOON
A tandem queue that consists of nodes with buffers of finite capacity and general blocking scheme is considered. The service time distribution of each node is exponential whose rate depends on the state of the node. The blocking scheme at a node may be different from that of other nodes. An approximation method for the system based on decomposition method is presented. The effectiveness of the method is investigated numerically.
JKSIAMv26n1 pp2348
PREDICTING KOREAN FRUIT PRICES USING LSTM ALGORITHM
TAESU PARK, JONGHAE KEUM, HOISUB KIM, YOUNG ROCK KIM, AND YOUNGHO MIN
In this paper, we provide predictive models for the market price of fruits, and analyze the performance of each fruit price predictive model. The data used to create the predictive models are fruit price data, weather data, and Korea composite stock price index (KOSPI) data. We collect these data through OpenAPI for 10 years period from year 2011 to year 2020. Six types of fruit price predictive models are constructed using the LSTM algorithm, a special form of deep learning RNN algorithm, and the performance is measured using the root mean square error. For each model, the data from year 2011 to year 2018 are trained to predict the fruit price in year 2019, and the data from year 2011 to year 2019 are trained to predict the fruit price in year 2020. By comparing the fruit price predictive models of year 2019 and those models of year 2020, the model with excellent efficiency is identified and the best model to provide the service is selected. The model we made will be available in other countries and regions as well.
JKSIAMv26n1 pp4966
RELIABILITY OF NUMERICAL SOLUTIONS OF THE GEULER PROCESS
DONG WON YU
The GEuler process has been proposed to overcome the difficulties of the calculation of the exponential function of the Jacobian. It is an explicit method that uses the exponential function of the scalar skewsymmetric matrix. We define the moving shapes of true solutions and the moving shapes of numerical solutions. It is discussed whether the moving shape of the numerical solution matches the moving shape of the true solution. The match rates of these two kinds of moving shapes are sequentially calculated by the GEuler process without using the true solution. It is shown that the closer the minimum match rate is to 100%, the more closely the numerical solutions follow the true solutions to the end. The minimum match rate indicates the reliability of the numerical solution calculated by the GEuler process. The graphs of the Lorenz system in Perko [1] are different from those drawn by the GEuler process. By the way, there is no basis for claiming that the Perko’s graphs are reliable.
JKSIAMv26n1 pp6775
ANALYSIS OF NONINTEGER ORDER THERMOELASTIC TEMPERATURE DISTRIBUTION AND THERMAL DEFLECTION OF THIN HOLLOW CIRCULAR DISK UNDER THE AXISYMMETRIC HEAT SUPPLY
SATISH G. KHAVALE AND KISHOR R. GAIKWAD
Analysis of noninteger order thermoelastic temperature distribution and it’s thermal deflection of thin hollow circular disk under the axisymmetric heat supply is investigated. Initially, the disk is kept at zero temperature. For t > 0 the parametric surfaces are thermally insulated and axisymmetric heat supply on the thickness of the disk. The governing heat conduction equation has been solved by integral transform technique, including MittagLeffler function. The results have been computed numerically and illustrated graphically with the help of PTCMathcad.
