• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.724-734
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• 2019

This study selected a representative small arm firing range and analyzed the distribution of heavy metal pollutants such as Pb, Cu, Zn, etc. For this the concentrations of heavy metals in soils, roots and leaves of plants, and water of the small arm firing range were measured. The concentrations of heavy metals in the effluent were also checked during precipitation. The concentration of lead in the samples collected from the top soil(0-5 cm) and sub soil(5-50 cm) near the target in the small arm firing range exceeded the concern level of the Soil Environment Conservation Act of Korea, but not in other soil samples. Plants that grow in soil heavily contaminated with lead showed a high lead concentration, especially in roots. However, the concentration of lead in effluent from the small arm firing range was less than 0.02 ppm. The concentration of copper and zinc in the small arm firing range did not surpass the concern level of the Soil Environment Conservation Act of Korea. Through this study more accurate information on the distribution of heavy metal pollution in the soil of the small arm firing range was obtained. Based on this research, we can conclude that some facility improvements can reduce the spreading of pollutants in the currently used small arm firing range and contribute to the design and operation of advanced small arm firing ranges.

• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.3
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• pp.323-330
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• 2018

In this paper, design and fabrication of a MSP(Multiple Scattering Points) discriminator for a simulated target measurement using a HRR(High Range Resolution) RADAR are described. The MSP discriminator is designed to provide a reference signal at the installed point on the simulated target in an outdoor test. The MSP discriminator is designed to have a remote control function that can turn the MSP discriminator on and off when the target moves to a remote location. While the MSP discriminator is off, the MSP discriminator is designed to be small enough not to spoil the target's unique RCS. The MSP discriminator consists of RF components in the Ku-band. In order to prevent spreading of the signal, a cable were added to the MSP discriminator to have an appropriate feedback loop delay considering the resolution of the RADAR. The fabricated MSP discriminator provided a reference scattering point as an RCS of approximately 1 dBsm. As a result, by using the MSP discriminator, the physical scattering points of the target were clearly identified in the measured signals with the RADAR.

• ALGAE
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• v.22 no.1
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• pp.17-21
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• 2007

Sargassum filicinum Harvey, a brown alga (Phaeophyceae) native to Northeastern Asia, has been recently reported from the coast of Southern California (USA). Here we report the occurrence and range extension of this introduced species, as we found the alga at La Jolla and Rancho Packard in Todos Santos Bay, Baja California, Mexico. The first collections of S. filicinum correspond to several immature plants, found on September 8, 2005, drifting in the intertidal zone at La Jolla. Later on November 9, 2006, we found a well-established population in Rancho Packard in the middle intertidal zone to 2 m depth. Since S. filicinum is an annual monoecious species with air bladders, the risk there is a high risk of spreading rapidly along the Pacific, as in the case for S. muticum. The population in Rancho Packard extends 500 m along the coast, consisting mainly of young plants with an average length of 30 cm and a density of 5 thallus/m2. This is the first record of this invasive species for the Mexican Pacific coast, and it represents the southern limit along the Pacific coast of North America. This finding suggests that this invasive species has successfully colonized the Pacific coast of North America and its distributional range is still expanding.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.5
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• pp.19-26
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• 2014

The advent of smart phones brought adverse effect between devices recently. For example, adverse effects of info-communication with advent of computer. Also, hacking threat aiming cyber space that is getting more advanced is spreading in terms of range and danger, so that it reaches the level that the nation has to concern. In this circumstance, crimes involving info-technology is now problem in society. As internet technology advances, it enlarges the range of hacker's threat to not only smart phones, but ships, aircrafts, buildings, and cars. It could be seen as social threat of between human and human, between machine and machine, and between human and machine. This study discuss these problems.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.2
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• pp.93-101
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• 1986

The behavior of a plane buoyant jet discharged vertically upward into a stagnant uniform environment is analyzed by continuity, momentum transport equation by numerical scheme. The governing equations are solved by finite difference method employing stream function and vorticity transport and Prandtl's turbulent model. Results for centerline velocities and temperatures, temperature distribution and flow pattern in receiving environment due to buoyant jet in the range of discharge densimetric Froude number of 4 to 32 show good agreement with published data. Spreading rate and dispersion ratio, which are required in integral type analysis of whole range of buoyant jet and have not been obtained yet, are derived in terms of discharge densimetric Froude number and vertical distance from source.

• Research in Community and Public Health Nursing
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• v.13 no.1
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• pp.57-67
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• 2002

Purpose: Chronic hepatic disease is caused by inappropriate management of the hepatitis B virus. In Korea. there is an increasing number of chronic hepatic patients. who are at risk of dying from liver failure or hepatocellular carcinoma. Therefore it is important to manage the hepatitis B virus appropriately. Method: The patients diagnosed with chronic hepatic disease or HBV carrier who registered at a community health center or hospital were assessed regarding health man agement status and educational needs. The data was collected from 179 persons by convenient sampling between May, 2000 and April. 2001. The data were was analyzed for general characteristics using the descriptive method, factors influencing educational needs and health management using t-test and ANOVA. Results: 1. The average health management score was 18.2 from 12 to 24 range. Those who unknown were unaware of the presence of HBsAg, attending the educational program and keeping undergoing treatment at the community health center or hospital were had a higher management score(p< .05). 2. The educational needs regarding nutritional management(64.8%) was the highest topic with chronic hepatitis patients. The second highest topic was spreading prevention among family members (52.0%), and keeping medication (45.8%), the degree of physical activities(44.1%), and spreading prevention in public(39.1%). Those who were unaware of the presence of HBsAg (p< .001), less than 12 months after HBsAg (+)(p< .05), keeping treatment (p< .05) were higher educational needs. 3. The use of alternative therapy was 27.9% of subjects. The subjects thought it was helpful for disease management(42.1%), mostly, family members and relatives recommended to use (57.9%), and medical regimen was ignored during the alternative therapy. Conclusion: Based on the results, an educational program about prevention of type B hepatitis and management for patients having type B hepatitis should be developed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.35-36
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• 2009

In this work, we demonstrate 800V 4H-SiC power DMOSFETs with several structural alterations to obtain a low threshold voltage ($V_{TH}$) and a high figure of merit ($V_B^2/R_{SP,ON}$). To optimize the device performance, we consider four design parameters; (a) the doping concentration ($N_{CSL}$) of current spreading layer (CSL) beneath the p-base region, (b) the thickness of p-base ($t_{BASE}$), (c) the doping concentration ($N_J$) and width ($W_J$) of a JFET region, (d) the doping concentration ($N_{EPI}$) and thickness ($t_{EPI}$) of epi-layer. These parameters are optimized using 2D numerical simulation and the 4H-SiC DMOSFET structure results in a threshold voltage ($V_{TH}$) below ~3.8V, and high figure of merit ($V_B^2/R_{SP,ON}$>${\sim}200MW/cm^2$) for a power MOSFET in $V_B$-800V range.

• Journal of KIISE:Computing Practices and Letters
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• v.7 no.6
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• pp.653-660
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• 2001

Recently, The range of Internet based information environment is spreading over core business area, as well as simple information provision area. Especially, with spreading WWW technology, markup language based technology is emerging as an important part in Internet based business. But, the data made by SGML can only see by using SGML Browser, so it has some problem in information providing at Internet, and compatibility of data between Data source. So, this study suggests essential architecture and technique for migrating from SGML to XML environment. In our study, we use 600MB SGML data that are selected from 3Tera DataBase of SGML as testing target for migration. We can reduce data displaying time after migration, can do mobile computing which is based on Internet as a result of this study. And the same technique and idea that is used in this study can apply to more large SGML Environment without changing. So, It will be very helpful to the reader who is interesting to migrate from SGML doc to XML doc.

• Journal of Welding and Joining
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• v.26 no.5
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• pp.43-48
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• 2008

Characteristics of Sn-1.7%Bi-0.7%Cu-0.6%In (hereafter, SBIC) lead-free solder was investigated in this study. The results from SBIC were compared to other lead-free solders such as Sn-3.5%Ag-0.7%Cu (hereafter, SAC), Sn-0.7%Cu (hereafter, SC), and lead-bearing Sn-37%Pb (hereafter, SP) alloy. Tensile properties of bulk solder, wettability, spreading index, bridge and dross were evaluated. As experimental results, tensile strength and elongation of SBIC was 62.5MPa and 21.5%, respectively. The tensile strength was comparable to that of SP solder. The wetting time of SBIC was 1.2 sec at $250^{\circ}C$, and its wetting properties including wetting force were as good as the SAC alloy. However, wettability of the SC was not so good as the SBIC and SAC. The spreading index of SBIC at $250^{\circ}C$ was 71 %, and it was similar level to those of SAC and SC solders. Bridging was not found for all solders of SBIC, SAC and SC in the range from 240 to $260^{\circ}C$. In dross test at $250^{\circ}C$ for an hour, the amount of dross produced from SBIC was about 57% compared to that from SAC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.591-593
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• 2019

LPWA has a small amount of data that can be transmitted at one time, but it can collect a very wide range of information, so it is suitable for gathering information of apartment meter or collecting data intermittently sent from industrial site. However, most of the application studies on LPWA are limited to outdoor, especially LOS environment, so it is difficult to collect information for application to apartment and industrial sites. In this paper, we have measured the communication coverage within the building, which is a NLOS environment, so that LPWA communication can be applied to apartments and industrial sites. For the experiment, LoRa module was created using sx1276, Class A was applied, and the spread factor was changed for each layer. As a result, in case of spreading factor 7 that shows increasing error and losses from the 7 floor, but the in case of spreading factor 12, the data could be seamlessly received even on the 9th floor without error and losses.