• Photonics industry news
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• s.30
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• pp.36-43
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• 2005

세계 광통신 부품 시장은 1990년대 중반부터 2000년 초까지 통신 네트워크 수요 증가에 따라 고성장을 이루었다. 하지만 2000년을 기점으로 매년 30%이상의 마이너스 성장은 관련 기업들의 매출감소와 수익성 저하로 이어졌고 이는 광통신 부품업체들의 사업정리 및 인원감축 등 구조 조정을 가속화하는 계기가 되었다.

• Photonics industry news
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• s.11
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• pp.16-19
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• 2002

국내통신서비스 산업의 시장구조가 데이터통신 중심으로 급격히 전환되고 있다. 국내 통신서비스 산업은 2001년 14%대의 성장을 시현했으며,2002년에도 13%정도의 양호한 성장세를 이어나갈 전망이다. 유무선을 망라한 음성서비스 분야의 성장세 둔화에도 불구하고, 통신서비스 산업이 이러한 성장세를 유지할 수 있는 것은 정보화의 열기를 바탕으로 한 데이터통신 수요릐 급증에 힘입은 바 크다

• Photonics industry news
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• s.10
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• pp.28-35
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• 2002

데이터 통신의 급격한 증가를 배경으로 대용량 통신이 가능한 광통신망 구축이 늘어나고 있다. 광통신망 구축을 위해서는 각종 시스템과 연동이 가능한 광통신 부품의 개발이 중요하고, 그 만큼 광통신 부품의 수요도 증가할 전망이다. 본 고에서는 주요 광통신 부품의 하나로 앞으로 큰 폭의 성장이 예상되고 있는 광증폭기에 대한 기술 개요와 시장 전망에 대해 살펴본다.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.411-426
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• 2009

Most of the metaheuristics are made by imitating the action of the animals. In this paper, we proposed Mine Algorithm. The Mine Algorithm is a metaheuristic that imitates the action of the human being. Speaking of search, the field in which the know-how and the heuristics of the human being are melted best is the mining industry. In the Mine Algorithm we formalize the action pattern of the human being by focusing the mine business. The Mine Algorithm uses various searching techniques fluently and shows equally good performance for broad problems. That is, it has good generality. We show the improved generality of the Mine Algorithm by the comparing experiments with the conventional metaheuristics.

• Tunnel and Underground Space
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• v.18 no.4
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• pp.272-279
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• 2008

This paper describes the development of a simple and quantitative subsidence hazard estimation method appropriate to Korean coal mines using gangway depth information only. In spite of simpleness of estimation method, this new method gives good results close to those obtained using influence function method when applying to a virtual rectangular excavation model and to a closed mine where actual subsidence occurred. Therefore, this method can be effectively applied to the identification of zones liable to subsidence over closed coal mine in Korea where the shape of extraction is very complex and usually unknown.

• Tunnel and Underground Space
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• v.23 no.5
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• pp.353-361
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• 2013

Previous studies for analyzing optimal haulage routes of dump trucks in open pit mines mostly used raster data. However, the raster data has several problems in performing optimal route analyses: (1) the jagged appearance of haulage roads according the cell resolution often causes overestimation of the travel cost; (2) it difficult to trace the topological relationships among haulage roads. These problems can be eliminated by using vector network data, however a new method is required to reflect the performance characteristics of a dump truck according to terrain gradient changes. This study presents a new method to create vector network data with the consideration of terrain gradient for analyzing optimal haulage routes of dump trucks in open pit mines. It consists of four procedures: (a) creating digital elevation models, (b) digitizing haulage road networks, (c) calculating the terrain gradient of haulage roads, and (d) calculating the average speed and travel time of a dump truck along haulage roads. A simple case study at the Roto South pit in the Pasir open pit coal mine, Indonesia is also presented to provide proof that the proposed method is easily compatible to ArcGIS Network Analyst software and is effective in finding optimal haulage routes of dump trucks with considering terrain gradient in open pit mines.

• Journal of Convergence for Information Technology
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• v.11 no.8
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• pp.92-99
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• 2021

Light-scattering fine particulate matter monitors can measure particulate matter (PM) concentrations in every second and can be designed in a portable size. They can measure the concentrations of various PM sizes (PM_1.0, PM_2.5, PM_4.0 and PM₁₀) with a single sensor. They measure the number and size of particulate matters and convert them to weight per volume (concentration). These devices show a large error for asian dust. This paper proposes a scheme that compensates the PM_2.5 concenstration error for asian dust by multiple linear regression machine learning in light-scattering PM monitors. This scheme can be effective with only two or three types of PM sizes. The experimental results compare a beta-ray PM monitor of national institute of environmental research and a light-scattering PM monitor during a month. The correlation coefficient (R²) of theses two devices was 0.927 without asian dust, but it was 0.763 due to asian dust during the entire experimental period and improved to 0.944 by the proposed machine learning.

• Spatial Information Research
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• v.20 no.4
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• pp.17-27
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• 2012

This study was performed to evaluate the spatial distribution of heavy metals using principal component analysis and Ordinary Kriging technique in the Gangwon Mine site. In the soils from the sub soil, the contents of Zn and Ni in the PC1 were gradually dispersed from south to north direction, while the components of Cd and Hg in the PC2 showed an increase significantly from middle-south area in the Gangwon Mine site. According to the cluster analysis, pollutant metals of As and Cu were presented a strong spatial autocorrelation structure in cluster D. The concentration of As was 0.83mg/kg and shown to increase from the south to north direction. The spatial distribution maps of the soil components using geostatistical method might be important in future soil remediation studies and help decision-makers assess the potential health risk affects of the abandoned mining sites.

• Economic and Environmental Geology
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• v.29 no.6
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• pp.665-676
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• 1996

Domestic metal mines have contributed to the national industrialization of Japan for over a century through their stable supply of raw materials. However, due to the changes which have taken place in the industries structure, mining industry has been shifted to downstream industries. At present, only three major mines are in production. In recent times, changing economic conditions have made it increasingly difficult to develop new base metal mines. Subsequently, the deposit type targeted has shifted from base metals to epithermal associated gold deposits which, if of sufficient grade and tonnage, can be economical. Accompanying the dramatic rise in the price of gold during the late 1970's, has been an increase in the geological information and our understanding of epithermal gold deposits around the Pacific rim region. In particular, the common acceptance of the plate tectonic theory and the correlation's between modem geothermal systems and fossil epithermal systems were most important developments. In 1988, the Mining Council authorized the domestic exploration of 19 districts, targeting epithermal gold mineralization. Since 1989 the Metal Mining Agency of Japan, semi-government organization, has been conducted gold exploration in such area. With new genetic concepts and new technologies, promising gold mineralization has been discovered. Two such areas which are at an advanced stage of exploration are Seta, in northern Hokkaido, and Noya, in central Kyushu.

• Resources Recycling
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• v.19 no.6
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• pp.11-26
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• 2010

In order to review the recycling status of urban mine resources in Japan, metal consumption, metal recycling rate and metal recycling industry such as iron scrap, end of life vehiclcs(ELV), waste home appliances and spent IT equipments were surveyed. Japan took rank of top class in the world on the metal consumption and urban mine stock reserve. Metal recycling industries in Japan have been developed through excellent technologies for mineral processing and non-ferrous smelting. On the other hand, the technologies for recycling of rare metals are being developed now. Recycling rate of EL V, waste home appliances and personal computer are higher than the guidelines of the legislative standard.