• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.488-493
• /
• 2011

The object of this study is to develope the program for analyzing the fluid flow and heat transfer of PMSM electric motor. The program will be mainly used for inexperienced users of CFD analysis. So it has to be performed using the geometry data and the heat source of each part only. Interface program for converting the given data to the instruction of pre-processor is developed. The conjugate heat transfer between a flow passage of the motor and inner parts consisting of rotor and stator is regarded. In order to reduce the computational time and memory storage, cyclic boundary condition is applied. For the numerical simulation, MRF(Multi-Reference Frame) method is used to consider rotating operation of the rotor and heat source is applied to the copper, wire, and magnetic parts in the motor. On the screen of computer, the users can show the velocity distributions and the contours such as pressure, turbulent kinetic energy, turbulent dissipation rate and temperature.

• Transactions of the Korean Society of Machine Tool Engineers
• /
• v.18 no.2
• /
• pp.170-177
• /
• 2009

The objective of this study is to evaluate an acoustic emission (AE) source characterization and fracture behavior of the SM45C steel by using back-propagation neural network (BPN). In previous research Ref. [8] about k-nearest neighbor classifier (k-NNC) continuity, we used K-means clustering method as an unsupervised learning method for obtaining multi-variate AE main data sets, such as AE counts, energy, amplitude, risetime, duration and counts to peak. Similarly, we applied k-NNC and BPN as a supervised learning method for obtaining multi-variate AE working data sets. According to the error of convergence for determinant criterion Wilk's ${\lambda}$, heuristic criteria D&B(Rij) and Tou values are discussed. As a result, in k-NNC before fracture signal is detected or when fracture signal is detected, showed that produce some empty classes in BPN. And we confirmed that could save trouble in AE signal processing if suitable error of convergence or acceptable encoding error give to BPN.

• International Journal of High-Rise Buildings
• /
• v.12 no.1
• /
• pp.63-74
• /
• 2023

Large-capacity public transportation systems, represented by urban metro lines, are the key to alleviating the significant increase in urbanization and motorization in China. But to improve the agglomeration effect of metro stations in a more accurate and targeted way requires scientific evaluation and classification of the surrounding areas of metro stations. As spatial and functional design are the core factors for urban renewal design, this study took Beijing as an example, using multi-source data to evaluate the morphology and functional composition surrounding areas of metro stations, and the Boston Consulting Group (BCG) matrix was used to classify and characterize each type of surrounding areas from morphological-functional dimensions. It shows a negative correlation of the mix-use index with the floor area ratio, and only about 20% of the areas achieve the ideal situation of high construction intensity with high mix-use diversity. Hoping to provide a reference for city managers and designers in dealing with the surrounding metro stations with different construction intensities in a more precise way.

• Korean Journal of Construction Engineering and Management
• /
• v.16 no.5
• /
• pp.105-113
• /
• 2015

In order to evaluate the energy performance of buildings, it is important to determine reliable information of energy utilization during operating phase. It is also required to establish the database which have the amounts of population deducted by objective filtering and analysis. In this study, all energy sources were applied to evaluate synthetically the energy performance of Multi-Family Housings(MFH) using district heating and the amounts of population were obtained sufficiently through data searching in Seoul and neighbor cities. Finally the database of source energy utilization and $CO_2$ emission in 325 MFH complexes were established through cross validation between data sources and statistical analysis. Additionally, further ideas have been proposed to improve existing MFH Management Information System.

• The KIPS Transactions:PartA
• /
• v.15A no.6
• /
• pp.317-324
• /
• 2008

In this paper, we propose a system which easily controls the existing serially connected multi-channel speakers in a general personal computer by using a USB(Universal Serial Bus) interface. The personal computer as a host of the USB interface analyzes a sound source and sends audio data in a real-time fashion by the use of the isochronous transmission, one of four transmission methods provided by the USB interface. In addition, a channel is assigned by means of the bulk transmission, one of four transmission methods provided by the USB interface. Transmitted data from the USB host are sent to each speaker through compression and packet generation process. Each speaker detects corresponding digital data and regenerates audio signals through DAC(Digital-to-Analog Converter). A user can easily select a sound source file and a channel by the use of a GUI environment in a personal computer.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.28A no.12
• /
• pp.1-11
• /
• 1991

Multi rate circuit switching ISDN which assumes a star topology consisting of LANs(local area networks) interconnected through a backbone MAN (metropolitan area network) is considered. The stations are classified into two categories data and voice stations they are characterized by different arrival rate and session-length (holding time) statistics. We first model the data and voice terminals as finite-source stations and derive analytically exact expressions for the end-to-end blocking probabilities. For more exact evaluation, these probabilities are calculated in terms of three components:circuit blocking probability, destination busy probability and concurrent busy probability. For large size systems, we develop an develop an iterative algorithm that provides a computationally efficient and fast method for the calculation of the end-to-end blocking probabilities.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
• /
• 2006.04a
• /
• pp.319-326
• /
• 2006

All around tile world there has been great human and economical damage continuously by disasters like the earthquakes and storms(Tsunami) in eastern asia which recently occurred, and like the New Orleams hurricane in USA. The situation is our countries damage from natural disasters due to heavy snow, storms, forest fires have been increasing In this research we obtained GSIS data of the 05' Yang-yang forest fire disaster area using multi-sensors like airborne laser data, GPS/INS, aerial photograph surveying. In result we produced digital topographical maps, digital elevation models, digital external models, digital images, infrared images. By, analyzing and comparing with past aerial photography we obtained the exact damage area, amount of damage, estimated tile areas where a landslide might occur, and we analyzed vegetations amount of damage and possibility of recovery.

• The Journal of the Acoustical Society of Korea
• /
• v.3 no.1
• /
• pp.16-24
• /
• 1984

The objective data and subjective data correlated in order to rate sound quality of loudspeaker system and these data were analyzed by the Factor Analysis and Multi-Dimensioinal Scaling. The dimensions yielded Factor Analysis were interpreted as "Contrast", "Metallic", "Rich", "Present" and their relation to physical variables were explored by studying the positions of loudspeaker systems in the respective dimension. When the subjective similarity degree of loudspeaker systems was compared with the objective similarity degree of loudspeaker systems by Multi-Dimensional Scaling, the similarity degree of sound pressure response in the listening room closely coincided with the subjective similarity degree regardless of sound source. This result implies the necessity of measurements taken not only in an anechoic room but also in a listening room in order to rate sound quality of loudspeaker systems.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.6
• /
• pp.1620-1634
• /
• 2023

This paper studies the task of embedding nodes with multiple graphs representing multiple information channels, which is useful in a large volume of network clustering tasks. By learning a node using multiple graphs, various characteristics of the node can be represented and embedded stably. Existing studies using multi-channel networks have been conducted by integrating heterogeneous graphs or limiting common nodes appearing in multiple graphs to have similar embeddings. Although these methods effectively represent nodes, it also has limitations by assuming that all networks provide the same amount of information. This paper proposes a method to overcome these limitations; The proposed method gives different weights according to the source graph when embedding nodes; the characteristics of the graph with more important information can be reflected more in the node. To this end, a novel method incorporating a multi-channel gate layer is proposed to weigh more important channels and ignore unnecessary data to embed a node with multiple graphs. Empirical experiments demonstrate the effectiveness of the proposed multi-channel-based embedding methods.

• Journal of Mechanical Science and Technology
• /
• v.16 no.9
• /
• pp.1054-1064
• /
• 2002

Numerical prediction of welding-induced residual stresses using the finite element method has been a common practice in the development or refinement of welded product designs. Various researchers have studied several thermal models associated with the welding process. Among these thermal models, ramp heat input and double-ellipsoid moving source have been investigated. These heat-source models predict the temperature fields and history with or without accuracy. However, these models can predict the thermal characteristics of the welding process that influence the formation of the inherent plastic strains, which ultimately determines the final state of residual stresses in the weldment. The magnitude and distribution of residual stresses are compared. Although the two models predict similar magnitude of the longitudinal stress, the double-ellipsoid moving source model predicts wider tensile stress zones than the other one. And, both the ramp heating and moving source models predict the stress results in reasonable agreement with the experimental data.