• KIPS Transactions on Software and Data Engineering
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• v.11 no.10
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• pp.399-408
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• 2022

ERC-20, the standard API for Ethereum token smart contracts, was introduced to ensure compatibility among applications such as wallets and decentralized exchanges. However, many compatibility vulnerability problems have existed because there is no rigorous functional specifications for each API nor conformance review tools for the standard. In this paper, we proposed a new review procedure and a tool to perform the procedure to review if ERC-20 token smart contract programs for the Ethereum blockchain conform to the de facto standards. Based on the knowledge from an analysis on the ERC-20 API functional behavior of the top 100 token smart contract programs in the existing Ethereum blockchain, a new specification for the de facto standard for ERC-20 API was explicitly defined. The new specification enabled us to design a systematic review method for Ethereum smart contract programs. We developed a tool to support this review method and we evaluated a few benchmark programs with the tool.

• 한국가시화정보학회:학술대회논문집
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• 2002.04a
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• pp.51-78
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• 2002

A number of research groups worldwide are studying electronic implants that can be mounted on retinal optic nerve/visual cortex to restore vision of patients suffering from retinal degeneration. The implants consist of a neural interface made of biocompatible materials, one or more integrated circuits for stimuli generation, a camera, an image processor, and a telemetric channel. The realization of these classes of neural prosthetic devices is largely due to the explosive development of micro- and nano-electronics technologies in the late $20^{th}$ century and biotechnologies more recently. Animal experiments showed promise and some human experiments are in progress to indicate that recognition of images can be obtained and improved over time. We, at NBS-ERC of SNU, have started our own retinal implant project in 2000. We have selected polyimide as the biomaterial for an epi-retinal stimulator. In-vitro and in-vivo biocompatibility studies have been performed on the electrode arrays. We have obtained good affinity to retinal pigment epithelial cells and no harmful effect. The implant also showed very good stability and safety in rabbit eye for 12 weeks. We have also demonstrated that through proper stimulation of inner retina, meaning vision can be obtained.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.544-546
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• 2008

An improved dual-path energy recovery circuit (ERC) using a current source and a voltage source for plasma display panel (PDP) is proposed. The proposed ERC uses the voltage source to charge a panel and the current source to discharge the panel. Thus, the proposed circuit can make the panel charge to $V_S$ and discharge to 0V, fully and it is possible to achieve zero voltage switching (ZVS) of all switches in H-bridge inverter and zero current switching (ZCS) of all switches in the ERC. Moreover, it has less conduction and switching loss in ERC devices by the dual energy recovery paths for charging and discharging the panel. Furthermore, it has features of canceling the gas discharge current, high performance and the low cost ERC components. The operation principle and features of the proposed ERC are presented in detail and verified with 42-inch SD PDP.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.475-477
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• 2005

국내에서 개발된 저궤도 관측위성에는 인텔계열의 프로세서가 사용되어 졌다. 인텔계열의 프로세서를 이용한 임베디드 시스템은 다양하고 상세한 기술문서들이 많이 제공될 수 있고 국내에도 관련된 기술 습득이 이루어져 있다는 장점이 있다. 그러나 프로세서에 대한 새로운 기술의 개발 및 적용이 단기간에 이루어지기 때문에 이를 이용한 시스템 개발에 계속적으로 개발비용 부담이 가중되고 선진국의 첨단기술 유출 방지를 위한 여러 규제들로 인해 인텔 계열의 프로세서를 사용한 위성용 임베디드 시스템 개발에 걸림돌이 되고 있다. 이러한 문제점들을 해결하기 위해 차세대 위성에 사용 가능한 탑재컴퓨터에 대한 조사 및 기술분석을 수행하였으며, 유럽에서 자체적으로 개발하여 위성용 탑재컴퓨터로 사용하고 있는 MCM-ERC52가 차세대 위성개발에 적합한 것으로 판단되었다. MCM-ERC32는 SPARC v.7을 기반으로 한 ERC32SC 프로세서를 이용한 탑재컴퓨터 보드로 향후 위성에 요구되는 다양한 기능들을 수행하기에 충분한 고성능 탑재컴퓨터이다. 국내에서는 MCM-ERC32를 이용한 개발 경험이 전무한 상황이며, 관련된 기술자료도 충분하지 않은 실정이다. 이에 따라 MCM-ERC32에 적합한 저궤도 위성용 탑재소프트웨어 개발을 위한 연구가 진행되고 있으며. 본 논문에서는 MCM-ERC32를 이용한 탑재소프트웨어 개발에 필요한 특징적인 ERC32 프로세서의 개념과 기능에 대해 소개하고자 한다.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.416-418
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• 2008

Cost effective and high efficiency energy recovery circuit (ERC) using an address voltage source is proposed. Different from prior ERC, the proposed circuit uses a voltage source to charge a panel and a current source to discharge the panel. As a result, it can be achieved zero voltage switching (ZVS) of switches in H-bridge inverter and zero current switching (ZCS) of switches of the ERC. Moreover, the proposed ERC can obtain high efficiency, high performance and the decrease of the cost and the size.

• Korean Journal of Materials Research
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• v.31 no.5
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• pp.286-295
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• 2021

This study attempts to find optimal conditions of the friction coefficient using a discrete element method (DEM) simulation with various friction coefficient conditions and three different grinding media with various ball sizes in a traditional ball mill (TBM). Using ball motion of the DEM simulation are obtained using the optimal friction coefficient compared with actual motion; photographs are taken by the digital camera and the snapshot images are analyzed. In the simulation, the rotation speed of the mill, the materials and velocity of the grinding media, and the friction coefficient between the balls and the wall of the pot are fixed as the actual experimental conditions. We observe the velocity according to the friction coefficient from the DEM simulation. The friction coefficient is found to increase with the velocity. Milling experiments using a traditional ball mill with the same experimental conditions as those of the DEM simulation are conducted to verify the simulated results. In addition, particle morphology change of copper powder is investigated and analyzed using scanning electron microscopy (SEM) for the milling experiment.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.106-106
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.569-569
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.567-567
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• 2003

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.554-554
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• 2003