• Economic and Environmental Geology
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• v.19 no.2
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• pp.85-96
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• 1986

The Bupyeong Silver mine which is located approximately 35km west of Seoul is currently the leading silver producer in Korea. The deposits occur as stockwork deposits hosted in Jurassic pyroclastic rocks. Occurrences of ore deposits and mineral paragenesis suggest a division of mineralization into four stages: Stage I, deposition of iron oxide and base metal sulfides; Stage II, deposition of tin oxide and silverm inerals; stage III, deposition of native silver and other silver minerals; Stage IV, formation of pyrite bearing siderite veinlets, Silver minerals in ore are native silver, argentite, freibergite, pyrargyrite, canfieldite, polybasite, dyscrasite and Ag-Fe-S mineral. The most important silver mineral is native silver among them. Chemical composition of important silver minerals were determined by electron probe microanalyser. Assay, size and modal analyses for floatation products were carried out. In floatation products, relative proportion of native silver for total important silver minerals have following ranges: feed, 64.7 to 74.74 wt.%; A-cleaner concentrate, 80.58 to 98.79 wt.%; and final tailing, 28.12 to 72. 57 wt. %. Average degree of liberation for native silver in feed and A-cleaner concentrate are 60.49% and 77.57% respectively. Negative relationship can be recognized between native silver and argentite in their abundance and behavior in floatation precesses.

• Economic and Environmental Geology
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• v.26 no.3
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• pp.279-287
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• 1993

In the zinc-lead (-silver) ores from the Yeonhwa 1 mine, stannite is widespread, though minor in amount It may be divided largely into two species on the basis of its chronological order during mineralization; i.e., stannite I formed in Stage I, and stannite II formed in Stage II. Also, the mineral may be classified into two types according to the difference of its associates; i.e., stannite 1 closely associated with sphalerite, and stannite 2 with galena. In general, the stannite 1 tends to predominate in the stannite I and the stannite 2 in the stannite II. The formation temperature and sulphur fugacity of stannite 1 deduced from stannite-sphalerite geothermometry are from 280 to $350^{\circ}C$ and from $10^{-11}$ to $10^{-8}$ atm.

• Fire Science and Engineering
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• v.17 no.2
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• pp.1-5
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• 2003

Recently, the occurrences of electrical fire have been suppressed by a residual current protective devices(RCD), a molded case circuit breaker(MCCB) and a fuse in case of an earth leakage, a short circuit and an over current. But it is impossible for the RCD to break the circuit in the case of the conductor fractures, the failure of pressure contacts on connecting points and the momentary short circuit of low voltage wiring. Therefore, it is require to study the constructive problem of the RCD. In this paper, we have tested the operation characteristics of the RCD according to the R load and R-L load in the conductor fractures, the failure of pressure contacts on connecting points and the momentary short circuit of low voltage wiring.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.243-258
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• 2011

With increasing interest in ubiquitous computing technology, an infrastructure for the short-distance wireless communication has been extended socially, bringing spotlight to the security system using the image or location. In case of existing security system, there have been issues such as the occurrences of blind spots, difficulty in recognizing multiple objects and storing of the unspecified objects. In order to solve this issue, zone-based location-estimation search system for the image have been suggested as an alternative based on the real-time location determination technology combined with image. This paper intends to suggest the search service for the image zone-based location-estimation. For this, it proposed the location determination algorism using IEEE 802.15.4/ZigBee's RSSI and for real-time image service, the RTP/RTCP protocol was applied. In order to combine the location and image, at the event of the entry of the specified target, the record of the time for image and the time of occurrence of the event on a global time standard, it has devised a time stamp, applying XML based meta data formation method based on the media's feature data based in connection with the location based data for the events of the object. Using the proposed meta data, the service mode which can search for the image from the point in time when the entry of the specified target was proposed.

• Korean journal of applied entomology
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• v.50 no.2
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• pp.141-149
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• 2011

Five erigonine spider species are described with illustrations: a new species, Saitonia pilosus n. sp., and four records new to the Korean spider fauna, Ceratinella brevis (Wider, 1834), Erigone atra Blackwall, 1833, Maso sundevalli (Westring, 1851), and Parasisis amurensis Eskov, 1984. The occurrences of four spider genera, Ceratinella Emerton, 1882, Maso Simon, 1884, Parasisis Eskov, 1984, and Saitonia Eskov, 1992, are also new to Korea.

• Journal of Korea Multimedia Society
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• v.14 no.2
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• pp.249-257
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• 2011

To protect the market for various products, existing authentication techniques using ID, hologram and RFID have been gradually developed. However, these methods can be easily exposed the authentication information, and also these exposed information easily copy. Thus, production of the counterfeit goods can not completely prevent. In this paper, to solve these problems, we designed JCVM file system for saving and managing the authentication information, user's information and a sales agency information into the smart card. And we designed and implemented an authentication protocol that can authenticate to avoiding exposure using processor of the smart card. Through this, this proposed scheme can prevent occurrences of the counterfeit goods. And also, can be used for authentication as any product that can attach the smart card.

• Journal of the Korean Society of Safety
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• v.20 no.2 s.70
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• pp.158-161
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• 2005

This research is about overflow cutoff valve for liquefied petroleum gas cylinders. This valve was developed based on Bernoulli's equation and Newton's equation. The structure of overflow cutoff valve was made by insert module instead of the ordinary valve that is used at present. Recently, the increase in use of gas for fuel in houses has resulted to more frequent occurrences of gas related accidents. In Korea, the government has made a law for the obligatory use of the cutoff valves. This cutoff valve is not ya developed. This research focuses on the use of over flow cutoff valve for LPG cylinders. If this valve is adapted, many accidents can be prevented.

• The Korean Journal of Ecology
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• v.13 no.2
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• pp.149-163
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• 1990

Two distinct spider communities were studied in the crowns and ground surfaces of pine plantations at Mt. Ungilsan, Kyonggi-do using pitfall traps and knock-down by spraying of an insecticide (D.D.V.P.) to sample spiders. There were 34 species of 11 families in the ground community and 41 species of 15 families in the crown community, with only 9 species being collected in both. Wandering spiders comprised 78.5% of the crown community and 90.8% of the ground community. Guild abundance and the most abundant families were distinctly different in the two habitats: agile hunters (Salticidae:32.4%) and nocturnal hunters (Clubionidae:19%) in the crown, runners (Lycocidae:32.8%) and nocturnal hunters (Gnaphosidae:31.2%) in the ground. Dominant species were Clubiona jucunda (Karsch) and Mymarachne japonica (Karsch) in the crown, while in the ground they were Pardosa laura Karsch and Gnaphosa silvicola. Species diversity(H ) had peaks in May, July and November in the ground community, while in the crown community peaks were in June and September. The seasonal trends of species diversity (H ) were due mainly to differences in the number of species and the numbers of individuals collected at each sample date rather than to differences in equitability among species. Spier guilds and dominant species have different seasonal patterns based on the temporal differences in prey availability in the two communities and the reduction of temporal overlap.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1691-1698
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• 2013

The purpose of this article is analyzing the economic impacts of abnormal climate on fall chinese cabbage farmers and consumers in Korea, with employing the equilibrium displacement model. Our results show that there were little difference in gross farm income, even though there were significant yield reductions due to abnormal climate changes. However periodic occurrences of abnormal climates caused serious damage to consumption levels which had declined by 10.6~17.1 percent with higher prices by 15.3~24.6 percent than normal climate years since 1990.

• Journal of the Korean Institute of Gas
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• v.5 no.2 s.14
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• pp.9-13
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• 2001

A complete spectrum of risk assessment including qualitative and quantitative approaches were performed for the POSCO's Batch Annealing Furnace (BAF) gas systems. The purpose of BAF is to enhance the quality of steel by annealing it with either hydrogen/nitrogen mixture gas or pure hydrogen gas. Number of gas leak scenarios were identified to generate frequency of their occurrences. With the hypothetical accident scenarios given, fire/explosion impact studies were performed to estimate magnitude of significant consequences. Several different indices were also presented from which practical safety improvement action items could be established.