• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.9
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• pp.2109-2116
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• 2014

This paper presents the implementation and design of the advanced WI-FI systems with beam-forming antenna that radiate their power to the direction of user equipment to improve the overall throughput, contrast to the general WI-FI systems equipped with omni-antenna. The system consists of patch array antenna, DSP, FPGA, and Qualcomm's commercial chip. The beam-forming system on the FPGA utilizes the packet information from Qualcomm's commercial chip to control the phase shifters and attenuators of the patch array antenna. The PCI express interface has been used to maximize the communication speed between DSP and FPGA. The directions of arrival of users are managed using the database, and each user is distinguished by the MAC address given from the packet information. When the system wants to transmit a packet to one user, it forms beams to the direction of arrival of the corresponding user stored in the database to maximize the throughput. Directions of arrival of users are estimated using the received preamble in the packet to make its SINR as high as possible. The proposed beam-forming system was implemented using an FPGA and Qualcommm's commercial chip together. The implemented system showed considerable throughput improvement over the existing general AP system with omni-directional antenna in the multi-user communication environment.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.4
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• pp.283-290
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• 2022

In this study, an IoT inspection system that can be linked with a server was developed using a gas timer and ESP-01 Wi-Fi module installed on a gas valve in the home. The server environment of the gas leak IoT inspection system was installed with APM (Apache, PHP, MySQL) to collect gas pressure data by generation so that leakage checks could be performed. In order to control the gas leak IoT inspection system, the app inventory was used to manage the gas leak check value in real time. In addition, user convenience has been enhanced so that membership management, WiFi settings, and leakage check values can be checked through mobile apps. In order to manage subscribers by region, the user list was checked by logging in in in the administrator mode so that the information on whether or not the leak test was conducted and the results could be provided. In addition, when the user presses the gas leak check button, the pressure is automatically checked, and the measured value is stored in the server, and when a gas leak occurs, the leakage check is performed after alarm and repair so that it can be used if normal. In addition, in order to prevent overlapping membership, membership management can be performed based on MAC addresses.

• Journal of Cadastre & Land InformatiX
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• v.54 no.1
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• pp.89-102
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• 2024

The recent advancements in Smart City and Digital Twin technologies have highlighted the critical role of integrating GIS and BIM in urban planning and construction projects. This integration ensures the consistency and accuracy of information, facilitating smooth information exchange. However, achieving interoperability requires standardization and effective project integration management strategies. This study proposes interoperability solutions for the integration of GIS and BIM for managing various projects. The research involves an in-depth analysis of the IFC schema and data structures based on the latest IFC4 version and proposes methods to ensure the consistency of reference point coordinates and coordinate systems. The study was conducted by setting the EPSG:5186 coordinate system, used by the National Geographic Information Institute's digital topographic map, and applying virtual shift origin coordinates. Through BIMvision, the results of the shape and error check coordinates' movement in the BIM model were reviewed, confirming that the error check coordinates moved consistently with the reference point coordinates. Additionally, it was verified that even when the coordinate system was changed to EPSG:5179 used by Naver Map and road name addresses, or EPSG:5181 used by Kakao Map, the BIM model's shape and coordinates remained consistently unchanged. Notably, by inputting the EPSG code information into the IFC file, the potential for coordinate system interoperability between projects was confirmed. Therefore, this study presents an integrated and systematic management approach for information sharing, automation processes, enhanced collaboration, and sustainable development of GIS and BIM. This is expected to improve compatibility across various software platforms, enhancing information consistency and efficiency across multiple projects.

• Childhood Kidney Diseases
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• v.7 no.2
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• pp.142-149
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• 2003

Purpose : The urinary mass screening program for the detection of urinary abnormalities in school aged population has been performed in Seoul since 1981. Nation-wide urinary mass screening program was also performed since 1998. The aim of this study was to analyze the cause and nature of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province Methods : The medical records of 44 cases of isolated proteinuria detected by chance on the urinary mass screening test in Busan and Kyungsangnam-do Province, and evaluated for urinary abnormalities at the pediatrics outpatients renal clinics of Busan Paik Hospital from April 2002 to August 2003 were reviewed prospectively. Results : The cause and incidence of isolated proteinuria were as follows; transient proteinuria 4 cases(9.1%), orthostatic proteinuria 36 cases(81.8%) and persistent proteinuria 4 cases (9.1%). The total protein amount of the 24 hour urine were $121.0{\pm}136.4\;mg$ in transient proteinuria, $179.1{\pm}130.0\;mg$ in orthostatic proteinuria and $1532.8{\pm}982.5\;mg$ in persistent proteinuria. In the orthostatic proteinuria group, the total protein amount of the 24 hour urine was in the range of 40-616 mg. Spot urine protein/creatinine ratio(PCR) were $0.10{\pm}0.01$ in transient proteinuria, $0.61{\pm}0.61$ in orthostatic proteinuria and $4.35{\pm}4.04$ in persistent proteinuria. In the orthostatic proteinuria group, spot me PCR was in the range of 0.09-2.32. Renal biopsy was peformed in 4 children of the persisitent proteinuria group. They showed minimal change in 1 case, membranoproliferatiye glomerulonephritis in 2 cases and secondary renal amyloidosis in 1 case. Conclusion : The majority of isolated proteinuria which was detected by chance on school urinary mass screening were transient or orthostatic proteinuria. Even though the incidence of persistent proteinuria was much lower, it is necessary to take care of these children regularly and continuously, because persistent proteinuria itself is a useful marker of the progressive renal problems.

• The KIPS Transactions:PartC
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• v.10C no.5
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• pp.625-634
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• 2003

More than a decade after its initial proposal, deployment of IP Multicast has been limited due to the problem of traffic control in multicast routing, multicast address allocation in global internet, reliable multicast transport techniques etc. Lately, according to increase of multicast application service such as internet broadcast, real time security information service etc., overlay multicast is developed as a new internet multicast technology. In this paper, we describe an overlay multicast protocol and propose fast join mechanism that considers switching of the tree. To find a potential parent, an existing search algorithm descends the tree from the root by one level at a time, and it causes long joining latency. Also, it is try to select the nearest node as a potential parent. However, it can't select the nearest node by the degree limit of the node. As a result, the generated tree has low efficiency. To reduce long joining latency and improve the efficiency of the tree, we propose searching two levels of the tree at a time. This method forwards joining request message to own children node. So, at ordinary times, there is no overhead to keep the tree. But the joining request came, the increasing number of searching messages will reduce a long joining latency. Also searching more nodes will be helpful to construct more efficient trees. In order to evaluate the performance of our fast join mechanism, we measure the metrics such as the search latency and the number of searched node and the number of switching by the number of members and degree limit. The simulation results show that the performance of our mechanism is superior to that of the existing mechanism.

• 대한공업교육학회지
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• v.32 no.1
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• pp.134-152
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• 2007

This study deals with the development of computer program which can restrict students to access to the unallowable web sites during the Internet based class. Our suggested program can find the student's access list to the unallowable sites, display it on the teacher's computer screen. Through the limitation of the student's access, teacher can enhance the efficiency of class and fulfill his educational purpose for the class. The use of our results leads to the effective and safe utilization of the Internet as the teaching tools in the class. Meanwhile, the typical method is to turn off the LAN (Local Area Network) power in order to limit the student's access to the unallowable web sites. Our program has been developed on the Linux operating systems in the small network environment. The program includes following five functions: the translation function to change the domain name into the IP(Internet Protocol) address, the search function to find the active students' computers, the packet snoop to capture the ongoing packets and investigate their contents, the comparison function to compare the captured packet contents with the predefined access restriction IP address list, and the restriction function to limit the network access when the destination IP address is equal to the IP address in the access restriction list. Our program can capture all passing packets through the computer laboratory in real time and exactly. In addition, it provides teacher's computer screen with the all relation information of students' access to the unallowable sites. Thus, teacher can limit the student's unallowable access immediately. The proposed program can be applied to the small network of the elementary, junior and senior high school. Our research results make a contribution toward the effective class management and the efficient computer laboratory management. The related researches provides teacher with the packet observation and the access limitation for only one host, but our suggested program provides teacher with those for all active hosts.

• Journal of Wetlands Research
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• v.18 no.3
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• pp.262-266
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• 2016

We investigated the characteristic demographics for visitors to Mujechi bog on Mt. Jungjok, with the purpose of developing a management strategy for the conservation and wise use of the montane wetland. Using daily visitor data from 2007, 2011, and 2015 we extracted and analyzed; visitation date, age, residential areas, purpose of visitation and the time allotted for the visit. The largest age cohort was the decade of the fifties(36.8%/total number of visitors) and followed by the decade of the forties(30.4%). The majority of visitors were from Ulsan(67%), Busan(16.6%), and Yangsan(10.8%). The visitors' primary objectives were to hike Mt. Jungjok(39-64.4%) or view Mujechi bog(18.7-51.8%) during the weekend. People visited more during the weekend than weekdays(F=6.19, p<0.002). In addition, there was a clear seasonality obvious in the monthly visits. The proportion of visitors were present in spring and fall, the month with the highest visitation rate was May at $15.6{\pm}2.8%$($mean{\pm}S.D.$). This increase in May was partly due to the desire to see the Korean azalea in bloom in the spring. Montane bog, like Mujechi, could be highly affected by disturbance(e.g. stamping, sediment inflow) caused by visitors. Therefore, it is suggested, based on the level of visitation that to reduce possible human disturbance effects, that either a seasonal restriction or a yearly alternation of trails be established. Visitors to the wetland should be restricted access to certain areas of the wetland, or be required to go in the accompaniment of a ranger or warden.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1793-1801
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• 2021

From 2015 to June 2020, the backscattering coefficients of 532 and 1064 nm measured using LIDAR and the depolarization ratio at 532 nm were used to separate the backscattering coefficient at 532 nm as three types as PM₁₀, PM_2.5-10, PM_2.5 according to particle size. The mass extinction efficiency (MEE) of three types was calculated using the mass concentration measured on the ground. The overall mean values of the calculated MEE were 5.1 ± 2.5, 1.7 ± 3.7, and 9.3 ± 6.3 m²/g in PM₁₀, PM_2.5-10, and PM_2.5, respectively. When the mass concentration of PM₁₀ and PM_2.5 was low, higher than average MEE was calculated, and it was confirmed that the MEE decreased as the mass concentration increased. When the MEE was calculated for each type according to the mixing degree of Asian dust, PM_2.5-10 was twice at pollution aerosol as high as 2.1 ± 2.8 m²/g, compare to pollution-dominated mixture, dust-dominated mixture, and pure dust of 1.1 ± 1.8, 1.4 ± 3.3, 1.1 ± 1.5 m²/g, respectively. However, PM_2.5 MEE showed similar values irrespective of type: 9.4 ± 6.5, 9.0 ± 5.8, 10.3 ± 7.5, and 9.1 ± 9.0 m²/g. The MEE of PM₁₀ was 5.6 ± 2.9, 4.4 ± 2.0, 3.6 ± 2.9, and 2.8 ± 2.4 m²/g in pollution aerosol (PA), pollution-dominated mixture (PDM), dust-dominated mixture (DDM), and pure dust (PD), respectively, and increased as the dust ratio value decreased. Even if the same type according to the same mass concentration or Asian dust mixture was shown, as the PM_2.5/PM₁₀ ratio decreased, the MEE of PM_2.5-10 decreased and the MEE of PM_2.5 showed a tendency to increase.

• Journal of agricultural medicine and community health
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• v.29 no.1
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• pp.65-75
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• 2004

Objectives: Immunizations have been one of the most effective measures preventing from infectious diseases. It is quite important national infectious disease prevention policy to keep the immunizations rate high and monitor the immunizations rate continuously. To do this, Korean CDC introduced the National Immunization Registry Program(NIRP) which has been implementing since 2000 at the Public Health Centers(PHC). The National Immunization Registry Program will be near completed after sharing, connecting and transfering vaccination data between public and private sector. The aims of this study was to evaluate the immunization module of non-chart system in private clinic with health information system of public health center(made by POSDATA Co., LTD) and immunization registry program(made by BIT Computer Co., LTD). Methods: The analysis and survey were done by specialists in medical, health field, and health information fields from 2001. November to 2002. January. We made the analysis and recommendation about the immunization module of non-chart system in private clinic. Results and Conclusions: To make improvement on immunization module, the system will be revised on various function like receipt and registration, preliminary medical examination, reference and inquiry, registration of vaccine, print-out various sheet, function of transfer vaccination data, issue function of vaccination certification, function of reminder and recall, function of statistical calculation, and management of vaccine stock. There are needs of an accurate assessment of current immunization module on each private non-chart system. And further studies will be necessary to make it an accurate system under changing health policy related national immunization program. We hope that the result of this study may contribute to establish the National Immunization Registry Program.