• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1050-1057
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• 2008

Wireless Mesh Networks (WMNs) have recently become a hot issue to support high link capacity in wireless access networks. The IEEE 802. I 1 standard which is mainly used for the network interface technology in WMNs supports up to 3 or 12 multiple channels according to the IEEE 802.11 specification. However, two important problems must be addressed when we design a channel assigmnent algorithm: channel dependency problem and channel scanning delay. The former occurs when the dynamic channel switching of an interface leads to the channel switching of other interfaces to maintain node connectivity. The latter happens per channel switching of the interface, and affects the network performance. Therefore, in this paper, we propose the Distance-Based Channel Assigmnent (DB-CA) scheme for multi-channel WMNs to solve such problems. In DB-CA, nodes just perform channel switching without channel scanning to communicate with neighboring nodes that operate on different channels. Furthermore, DB-CA minimizes the interference of channels being used by nodes near the gateway in WMNs. Our simulation results show that DB-CA achieves improved performance in WMNs.

• Journal of Food Hygiene and Safety
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• v.35 no.6
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• pp.607-617
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• 2020

Human bio-monitoring (HBM) data is a very important resource for tracking total exposure and concentrations of a parent chemical or its metabolites in human biomarkers. However, until now, it was difficult to execute the integration of different types of HBM data due to incompatibility problems caused by gaps in study design, chemical description and coding system between different sources in Korea. In this study, we presented a standardized code system and HBM knowledge model (KM) based on relational database modeling methodology. For this purpose, we used 11 raw datasets collected from the Ministry of Food and Drug Safety (MFDS) between 2006 and 2018. We then constructed the HBM database (DB) using a total of 205,491 concentration-related data points for 18,870 participants and 86 chemicals. In addition, we developed a summary report-type statistical analysis program to verify the inputted HBM datasets. This study will contribute to promoting the sustainable creation and versatile utilization of big-data for HBM results at the MFDS.

• Survey Research
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• v.10 no.3
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• pp.157-172
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• 2009

For a survey research in which the characteristics of the population of interest are investigated from a sample, representativeness of the sampling frame is one of the most important part to be considered. If the sampling frame fails to represent the population properly, statistical procedures based on the even efficient sampling design result in significant nonsampling biases and thus the statistical validities of the results could be damaged. But the construction of the reliable sampling frame that covers the population properly costs money and time and thus the sampling frame based on a census or a large scale survey is often used in practice. For example, the sampling frame based on the population households census is used for many household surveys in Korea. But due to the time difference between the census and a survey of interest, the sampling frame constructed from the census is expected to fail to cover the population of interest. Especially, one could expect a large amount of population and household movement in a large city like Seoul. Thus in our research, we considered the construction of new sampling frame and the procedure of sample selection for 2008 Seoul survey. We analyzed the sampling frame based on 2005 population households census and found that it does not represent the population properly. Thus, we proposed a new sampling frame based on resident registration DB for 2008 Seoul survey. We also proposed the sampling weights and estimator of the population mean based on the sample selected from the newly constructed sampling frame.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.4
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• pp.44-51
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• 2005

In this study, the method of extracting road centerline's coordinate and road facilities is presented using RC helicopter photogrammetry system. From the survey of extracted road centerline, the errors turned out to be -0.117m ~ 0.103m on the X-axis and -0.014m ~ 0.009m on the Y-axis when RC Helicopter photogrammetry system utilized. By application of this system, hereafter, not only management of road facilities but also construction of DB would be enable which need positioning and design of alignment on the access is not easy area such as traffic congestion or toparchy area.

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.753-758
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• 2002

In this paper, low voltage 3V CMOS programmable gain amplifier(PGA) for using in the transmitter and receiver of ADSL analog front-end is designed. The designed receive PGA is connected with 1.1MHz continuous lowpass fillet and controls the gain from 0dB to 30dB. And also the transmitter PGA is connected with 138KHz lowpass filter and controls the gain from -15dB to 0dB. The gain of All PGAs can be programmed by digital logic circuits and main controller. The designed PGAs are verified using HSPICE simulation with $0.35\mu{m}$ CMOS parameter.

• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.231-237
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• 2017

The profile of unpaved road is an important issue in the reliability of endurance test. Efforts on measuring 2D road profile and analyzing the severity have been continued in the study of performing reliable endurance test evaluations through reflecting the results of such measurement and analysis. However, 2D road profile has limitation in measuring the profile in the road width direction because data is obtained along the trailer wheel track. Therefore, in order to measure 3-dimensional shape of road surface and construct severity DB of 3D road profile, Changwon Proving Ground(CPG) of Agency for Defense Development(ADD) developed 3D profilometer which is composed of laser scanner, IMU, GPS, encoder and so on. This paper focuses on the analysis of unpaved road severity using 3D road profile for army operation roads. This results will be used to manage test courses severity of CPG.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.428-432
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• 2005

This paper has studied the concept and technical factors of e-Learning system to which we intend to apply domestic biodiversity information. This article describes how we analyzed and designed the e-learning system to serve biodiversity information as e-Learning contents. It would be useful for the public and students if this information are organized and provided as e-learning contents especially in our country which has well-established network infrastructure considering the limited land space. It is expected that the establishment of e-Learning system based on this proposed design will help students and public to access and team biodiversity on cyber space.

• Journal of Korea Multimedia Society
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• v.25 no.1
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• pp.135-143
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• 2022

In order to convert Korean folk paintings called Minhwa, a part of traditional Korean heritage, into DBs, it is necessary to design a classification system suitable for the characteristics of folk paintings. A classification system and the generating of unique codes are required to classify and save them. To realize this, a basic classification system was created by listing objects depicted in folk paintings, and keywords were extracted by reclassifying them for each object. In order to assign a unique code to each piece, we organize the English names of each Minhwa since the English names of the folk painting contain the names of objects. The code name is extracted by applying the order of nouns and consonant priority rules in English names and attaching five Arabic numerals. These codes are later assigned to each image file stored in the database and are input together with the keyword. The Minhwa DB constructed in this way enables storage and search centered on objects and keywords and the intuitive inferring of the type of object from the code name.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.70-79
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• 2014

Following the technology developments of traffic network and communication for the wide area, the importance of the cooperation system to vitalize the wide area economy is increasing. Therefore, in this study, DongNam Kwon industry information system is established for the industrial information sharing based on GIS in the DongNam Kwon wide area economy. The DongNam Kwon is an industrial integration area centered with the manufacturing so that the operation of effective industrial cluster and cooperation systems are required across the administrational boundaries. To establish the database of the information, the information system was established utilizing already established industrial databases in Busan, Ulsan and Gyeongnam. But, various issues caused by the discordances among the data of each local government and the insufficiency of GIS based location information have been found. According to the analysis, the standardization considering the courses of collection, distributions and utilization are required immediately to solve the issues. This study establishes an 2-way industrial information system enabling the information creation and the phased approach between the administrator and the user in the bi-directions on the web by utilizing cadastral and numerical maps. The result of this study would have a meaning in providing a fundamental frame for cooperative responses and cooperation system for DongNam Kwon's industrial promotion using industrial information sharing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.614-616
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• 2015

Current U-Healthcare has become specialized in Wellness center in the prevention of future health care concept of a health center, treatment. Wellness is the development of which has been emerging field of fitness system to evolve along with the key areas of U-Healthcare. Traditional Fitness system, one between the trainer and the user: 1. Consultation was only possible, the number of trainers are limited, this problem can be reduced individual coaching time existed as more number of users who can receive coaching at certain times of the day. In this paper, we design a mechanism that allows management by grouping field value of a DB table in the user's BMI(Body Mass Index) index and fitness trainer system to efficiently coaching a plurality of users similar BMI index.