• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.403-409
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• 2015

The Quasi-Zenith Satellite System (QZSS), a dedicated regional Japanese satellite system currently under development, was designed to complement the performance of the Global Positioning System (GPS). The high elevation angle of the QZSS satellite is expected to enhance the effectiveness of GPS in urban environments. Thus, the work described in this paper, aimed to investigate the effect of QZSS on GPS performance, by processing the GPS and QZSS measurements recorded at the Bohyunsan reference station in South Korea. We used these data, to evaluate the satellite visibility, carrier-to-noise density (C/No), performance of single point positioning, and Dilution of Precision (DOP). The QZSS satellite is currently available over South Korea for 19 hours at an elevation angle of more than 10 degrees. The results showed that the impact of the QZSS on users' vertical positioning is greatest when the satellite is above 80 degrees of elevation. As for Precise Point Positioning (PPP) performance, the combined GPS/QZSS kinematic PPP was found to improve the positioning accuracy compared to the GPS only kinematic PPP.

• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1061-1064
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• 2004

Molecular visualization software has the common objective of manipulation and interpretation of data from numerical simulations. They visualize many complicated molecular structures with personal computer and workstation, to help analyze a large quantity of data produced by various computational methods. However, users are often discouraged from using these tools for visualization and analysis due to the difficult and complicated user interface. In this regard, we have developed an easy-to-use three-dimensional molecular visualization and analysis program named POSMOL. This has been developed on the Microsoft Windows platform for the easy and convenient user environment, as a compact program which reads outputs from various computational chemistry software without editing or changing data. The program animates vibration modes which are needed for locating minima and transition states in computational chemistry, draws two and three dimensional (2D and 3D) views of molecular orbitals (including their atomic orbital components and these partial sums) together with molecular systems, measures various geometrical parameters, and edits molecules and molecular structures.

• Journal of the Korean Institute of Landscape Architecture
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• v.19 no.3
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• pp.72-86
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• 1991

In the study I analyzed the relationship between the characteristics of the user's residential environment and his or her use of openspace. I find out that there are little correlationship between building form and use factors. Also, there are no relationship between persons per room and use factors. Only the physical distance and the location of the building site is correlated with the use factor. In testing the hypotheses, I discovered very little to support the "physical deterministic" notion. I generally was not able to explain the behavior of open space users on the basis of the physical parameters selected to describe the user's residential environment. This, I believe, indicates that there probably are many other variables that play a more important role than those pertaining to the density and form of the residential environment. It is necessary to find out more variables affecting the use of openspace in the neighbourhoods, such as the charecteristics of user group. Also, it is necessary to apply the study to the other sites or the other cities in Korea to compare with the results.

• KIISE Transactions on Computing Practices
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• v.22 no.11
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• pp.567-575
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• 2016

With the popularity of smartphone, user's location information is of great interest as mobile apps based on the location information are increasing. In this paper, we are interested in analyzing user's speed data based on the location information. It is not uncommon to observe locations with great measurement errors, removing them is necessary. The distribution of speed can be considered as a mixture model in accordance with transportation means. We identify a tail part as a component of a mixture model and fit a simple parametric model to the tail part of the speed distribution.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.36-42
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• 2009

A series of heavy rainfall, typhoon and earthquake disasters caused a proportionately large number of deaths among the elderly in the year 2004 in Japan. In response to these tragedies, the national government set up committees to reduce damage within the disaster vulnerable population for the next three years. The discussions in the committee led to a new conceptualization that disaster vulnerability was caused by a lack of interaction between a person's special needs and the environment's capacity and resources to meet them. This person-in-environment model of hazard vulnerability was applied to those who resided in the Nankai-Tonankai tsunami hazard-prone area. 123 home care service users were interviewed in terms of their self-evacuation ability, degree of social isolation, and building weakness as well as tsunami exposure risks. Results were quantified and scores of person-in-environmentmodel hazard vulnerability were obtained. These scores were then used to visualize socially created vulnerability by means of weighted kernel density mapping of both persons with special needs (PSN's) and persons with special needs at times of disaster (PSND's).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.628-649
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• 2017

Security and resource-saving are both demands of the fifth generation (5G) wireless networks. In this paper, we study the secrecy spectrum efficiency (SSE) and secrecy energy efficiency (SEE) of a K-tier massive multiple-input multiple-output (MIMO) enabled heterogeneous cellular network (HetNet), in which artificial noise (AN) are employed for secrecy enhancement. Assuming (i) independent Poisson point process model for the locations of base stations (BSs) of each tier as well as that of eavesdroppers, (ii) zero-forcing precoding at the macrocell BSs (MBSs), and (iii) maximum average received power-based cell selection, the tractable lower bound expressions for SSE and SEE of massive MIMO enabled HetNets are derived. Then, the influences on secrecy oriented spectrum and energy efficiency performance caused by the power allocation for AN, transmit antenna number, number of users served by each MBS, and eavesdropper density are analyzed respectively. Moreover, the analysis accuracy is verified by Monte Carlo simulations.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.17 no.4
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• pp.383-391
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• 1999

This paper describe the interpretation of population density of rice pest in 1998 all over the country using GIS technique and the development of Internet GIS for sharing and analyzing information through Internee. Due to the widespread availability of computer network, GIS solution is available to users on your Internet via the web. Through Internet Rice Pest Information System developed visually the related information of rice pest all over the country and also interactive communication with the web interface concerning the existing system which provides simply static map, texts and numerical statement on the internet, the advantages of developed system are visually information, dynamic map, easy user interface and interactive map through the internet. This system provide more effective method of rice pest data to client.

• Journal of KIISE
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• v.43 no.2
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• pp.135-142
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• 2016

Visual analysis of spatiotemporal data has focused on a variety of techniques for analyzing and exploring the data. The goal of these techniques is to explore the spatiotemporal data using time information, discover patterns in the data, and analyze spatiotemporal data. The overall trend flow patterns help users analyze geo-referenced temporal events. However, it is difficult to extract and visualize overall trend flow patterns using data that has no trajectory information for movements. In order to visualize overall trend flow patterns, in this paper, we estimate continuous distributions of discrete events over time using KDE, and we extract vector fields from the continuous distributions using the gravity model. We then apply our technique on twitter data to validate techniques.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.118-123
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• 2020

In this paper, the design method of asynchronous nonvolatile memory module that can efficiently process and store large amounts of data without loss when the power turned off is proposed and implemented. PSRAM, which takes advantage of DRAM and SRAM, was used for data processing, and NAND flash memory was used for data storage and backup. The problem of a lot of signal interference due to the characteristics of memory devices was solved through PCB design using high-density integration technology. In addition, a boost circuit using the super capacitor of 0.47F was designed to supply sufficient power to the system during the time to back up data when the power is off. As a result, an asynchronous nonvolatile memory module was designed and implemented that guarantees reliability and stability and can semi-permanently store data for about 10 years. The proposed method solved the problem of frequent data loss in industrial sites and presented the possibility of commercialization by providing convenience to users and managers.

• Journal of Information Processing Systems
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• v.15 no.6
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• pp.1422-1437
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• 2019

With the rapid development of the Internet and the Mobile Internet, social communication based on the network has become a life style for many people. WeChat is an online social platform, for about one billion users, therefore, it is meaningful to study the spreading and evolution mechanism of the rumor on the WeChat social circle. The Rumor was injected into the WeChat social circle by certain individuals, and the communication and the evolution occur among the nodes within the circle; after the refuting-rumor-information injected into the circle, subsequently,the density of four types of nodes, including the Susceptible, the Latent, the Infective, and the Recovery changes, which results in evolving the WeChat social circle system. In the study, the evolution characteristics of the four node types are analyzed, through construction of the evolution equation. The evolution process of the rumor injection and the refuting-rumor-information injection is simulated through the structure of the virtual social network, and the evolution laws of the four states are depicted by figures. The significant results from this study suggest that the spreading and evolving of the rumors are closely related to the nodes degree on the WeChat social circle.