• Proceedings of the Korea Information Processing Society Conference
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• 2023.05a
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• pp.76-77
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• 2023

가상 화폐가 금융권에 등장한 이후 가상화폐를 얻기 위한 채굴이라는 작업이 각광받기 시작하였다. 하지만 시간이 흐르면서 채굴기를 가동하는데 소모되는 전력보다 채굴에 따른 보상의 양이 적어지면서 수익 구조가 무너지기 시작하였다. 본 논문에서는 태양열 에너지 발전을 통해 가상화폐를 채굴하는 방법을 제안한다. 태양열 발전을 위한 시스템을 설계하고 수익성을 증명하였다. 그 결과 태양열 발전 설비로 생산한 전력을 판매하여 얻는 수익보다 채굴기를 가동하여 얻는 수익이 약 17% 더 많은 것을 알 수 있었다. 채굴 시장의 규모는 블록체인 시장 규모에 비례하여 증가하고 있기 때문에 채굴 시장의 전망도 증가할 것으로 예상된다.

• Proceedings of the Korea Database Society Conference
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• 1999.06a
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• pp.105-113
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• 1999

최근 데이터와 데이터베이스의 폭발적 증가에 따라 무한한 데이터 속에서 정보나 지식을 찾고자하는 지식채굴과정 (knowledge discovery process)에 대한 관심이 높아지고 있다. 특히 기업 내외부 데이터베이스 뿐만 아니라 데이터웨어하우스 (data warehouse)를 기반으로 하는 OLAP환경에서의 데이터와 인터넷을 통한 웹 (web)에서의 정보 등 정보원의 다양화와 첨단화에 따라 다양한 환경 하에서의 지식채굴과정이 요구되고 있다. 본 연구에서는 인터넷 상의 지식을 효과적으로 채굴하기 위한 지식채굴과정을 제안한다. 제안된 지식채굴과정은 명시지 (explicit knowledge)외에 암묵지 (tacit knowledge)를 지식채굴과정에 반영하기 위해 선행지식베이스 (prior knowledge base)와 선행지식관리시스템 (prior knowledge management system)을 이용한다. 선행지식관리시스템은 퍼지인식도(fuzzy cognitive map)를 이용하여 선행지식베이스를 구축하여 이를 통해 웹에서 찾고자 하는 유용한 정보를 정의하고 추출된 정보를 지식변환시스템 (knowledge transformation system)을 통해 통합적인 추론과정에 사용할 수 있는 형태로 변환한다. 제안된 연구모형의 유용성을 검증하기 위하여 재무자료에 선행지식을 제외한 자료와 선행지식을 포함한 자료를 사례기반추론 (case-based reasoning)을 이용하여 실험한 결과, 제안된 지식채굴과정이 유용한 것으로 나타났다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 1999.03a
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• pp.105-113
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• 1999

최근 데이터와 데이터베이스의 폭발적 증가에 따라 무한한 데이터 속에서 정보나 지식을 찾고자하는 지식채굴과정(Knowledge discovery process)에 대한 관심이 높아지고 있다. 특히 기업 내외부 데이터베이스 뿐만 아니라 데이터웨어하우스(data warehouse)를 기반으로 하는 OLAP 환경에서의 데이터와 인터넷을 통한 웹(web)에서의 정보 등 정보원의 다양화와 첨단화에 따라 다양한 환경 하에서의 지식 채굴과정이 요구되고 있다. 본 연구에서는 인터넷 상의 지식을 효과적으로 채굴하기 위한 지식채굴과정을 제안한다. 제안된 지식채굴과정은 명시지(explicit knowledge)외에 암묵지(tacit knowledge)를 지식채굴과정에 반영하기 위해 선행지식베이스(prior knowledge base)와 선행지식관리시스템(prior knowledge management system)을 이용한다. 선행지식관리시스템은 퍼지인식도(fuzzy cognitive map)를 이용하여 선행지식베이스를 구축하여 이를 통해 웹에서 찾고자 하는 유용한 정보를 정의하고 추출된 정보를 지식변환시스템(knowledge transformation system)을 통해 통합적인 추론과정에 사용할 수 있는 형태로 변환한다. 제안된 연구모형의 유용성을 검증하기 위하여 재무자료에 선행지식을 제외한 자료와 선행지식을 포함한 자료를 사례기반추론 (case-based reasoning)을 이용하여 실험한 결과, 제안된 지식채굴과정이 유용한 것으로 나타났다.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.2
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• pp.303-310
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• 2018

Bitcoin (BTC) is a cryptocurrency proposed by Satoshi Nakamoto in 2009. Bitcoin makes its transactions with no central authorities. This decentralization is accomplished with its mining, which is an operation that makes people compete to solve math puzzles to include new transactions into block, and eventually block chains (ledger) of bitcoin. Because miners need to solve a complex puzzles, they need a lot of computing resources. In return for miners' resources, bitcoin network gives newly minted bitcoins as a reward to miners when they succeed in mining. To prevent inflation, the reward is halved every 4 years. For example, in 2009 block reward was 50 BTC, but today, the block reward is 12.5 BTC. On the other hands, exchange rate for bitcoin and Korean Won (KRW) changed drastically from 924,000 KRW/BTC (January 12th, 2017) to 16,103,306 KRW/BTC (December 10th, 2017), which made mining more attractive. However, there are no rigorous researches on the profitability of bitcoin mining. In this paper, we evaluate the profitability of bitcoin mining.

• Tunnel and Underground Space
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• v.11 no.2
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• pp.174-181
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• 2001

The cavities created by underground mining, if remained unfilled, can cause ground settlement and surface subsidence as a result of relaxation and breakdown of the carven roof. Construction of structures above the underground mine cavity will have serious problems concerning both structural stability and safely even if the cavity is back-filled. This study was conducted to confirm the location and condition of the cavern as well as the state of the back-fill in A mine area using core logging and borehole camera. The bearing capacity and other mechanical properties of the ground were also measured by the standard penetration test(SPT). Obtained data were used to assess the stability of the ground and the structures to be built by numerical analysis using FLAC. The site investigation results showed that the mine cavities were filled with materials such as boulder and silty sand(SM by unified classification). Result of the numerical analyses indicated that constructing building structures on the over-lying ground above the filled cavities is secure against the potential problems such as surface subsidence and ground settlement.

• Review of KIISC
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• v.28 no.3
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• pp.33-37
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• 2018

암호 화폐가 다양해지면서 암호 화폐를 채굴하는 방법 또한 다양한 방향으로 생겨났다. CyptoNote라는 프로토콜을 이용한 암호 화폐 중 하나인 모네로를 채굴할 때 메모리를 중점적으로 사용하도록 되어 있다. Coinhive는 광고 없이 수익을 내기위한 방법으로 웹브라우저를 이용한 모네로를 채굴하는 API를 만들었다. 하지만 본래의 목적과 다르게 API를 악의적으로 사용하여 웹브라우저 방문자의 동의 없이 채굴하는 공격인 크립토재킹이 증가하게 되었다. 이러한 공격을 막기 위해 브라우저 확장 어플리케이션이 등장하였으나, 공격자는 이를 우회하기 위해 자바스크립트 난독화를 사용하고 있다. 본 논문에서는, 크립토재킹에 대한 연구동향을 분석하고자 한다.

• Food Science and Preservation
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• v.12 no.6
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• pp.529-533
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• 2005

The respiratory characteristics of Korean fresh ginseng were investigated from the aspect of picking season, size, and storage temperature and period to get basic data for extension of shelf-life. The respiration rate of fresh ginseng picked in March was 4.09 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$. It was gradually increased to August, 7.88 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and then decreased continuously until November. Although the rate of fresh ginseng was different by picking season, the respiration quotient showed the same level, $1.03\~1.07$. Respiration rate by size was ranged from 3.47 to 5.69 mL $CO_2/kg{\cdot}hr$ at $0^{\circ}C$, and smaller in the size was higher in the rate. $Q_{10}$ value of fresh ginseng was $2.68\~2.88$ when the temperature increased from $0^{\circ}C\;to\;10^{\circ}C$ and $1.77\~2.16$ from $10^{\circ}C\;to\;20^{\circ}C$, and it was slightly different by picking season. At the beginning of storage the respiration rate was 7.0 mL $CO_2/kg{\cdot}hr$ and it was .decreased to 3.38 mL $CO_2/kg{\cdot}hr$ after storage for 90 days at $0^{\circ}C$.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.701-714
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• 2018

The purpose of this study is to show the possibility of 3-dimensional modeling of open-pit limestone mine by using a rotary-wing unmanned aerial vehicle, a drone, and to estimate the amount of mining before and after mining of limestone by explosive blasting. Analysis of the image duplication of the mine has shown that it is possible to achieve high image quality. Analysis of each axis error at the shooting position after analyzing the distortions through camera calibration was shown the allowable range. As a result of estimating the amount of mining before and after explosive blasting, it was possible to estimate the amount of mining of a wide range quickly and accurately in a relatively short time. In conclusion, it is considered that the drone of a rotary-wing unmanned aerial vehicle can be usefully used for the monitoring of open-pit limestone mines and the estimation of the amount of mining. Furthermore, it is expected that this method will be utilized for periodic monitoring of construction sites and road slopes as well as open-pit mines in the future.

• Tunnel and Underground Space
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• v.10 no.1
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• pp.80-91
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• 2000

Open cut mining of limestone is generally considered to be more advantageous than underground mining in recovery, grade control, economics, and safety, but it causes substantial environmental pollutants such as ground vibration, noise, dust. It also changes ground surface and may destroy vegetation. The Halla limestone mine which lies adjacent to Baikdu mountains range is selected for a model study. To reduce environmental hazards, and to conserve original surface and woods, both open cut and underground mining methods must be adopted. In case of sub-level sloping. a unit block of 87m high, 70m wide, and 100∼l20m long is suggested with an estimated overall recovery of 42%. Some suggestions to reduce the environmental hazards are also included. The followings must be considered in determining the degree of fragmentation; the discontinuity conditions in the rock mass and the charge concentration both at the bottom and column of the hole. In addition to adopting a barrier wall for reducing environmental hazards, the probable production from underground mining is also discussed.

• Tunnel and Underground Space
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• v.19 no.2
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• pp.107-122
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• 2009

Insufficient reinforcement for maximizing payability and benefits in mining cavities causes subsidence problems and it threatens residents' lives and properties. So many reinforcement management methods are developed and now various methods are being applied in the field. Among them, a filling method which sends reinforcement materials in the cavities is used extensively. However, domestic geological condition and coal mining methods are so complicate that make many steep cavities. Because of those problems, it is difficult to apply foreign methods directly, which is valid for horizontal cavities. In this study, the injection volume of quick setting grouting material which is developed for filling cavities in domestic condition and the shape of consolidated bodies are investigated. And a programming method for estimating proper injection amounts of filling materials is proposed. The results are verified by numerical analysis using UDEC.