대동맥 박리 환자 혈관 CT 이미지 복원을 통한 혈액 유동해석

허윤석,허윤석,남창욱,김윤년 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.4-4

Photocatalytic microbial sterilization using nanostructured graphitic carbon nitride (g-CN)

허윤석,오서영,허남수,이선욱,홍원희 한국공업화학회 2015 한국공업화학회 연구논문 초록집 Vol.2015 No.0

Polymeric graphitic carbon nitride (g-C3N4), which has an optical band gap of 2.7 eV, is the most stable allotrope of carbon nitride, and its potential applications for energy conversion, gas sensors, and solar cells have been reported. However, scarce efforts have been made to employ g-C3N4 as the active material for photocatalytic microbial sterilization. We prepared a rod-type g-C3N4 via self-assembly process. The as-prepared rod-type g-C3N4 with a length of 10-20 μm showed enhanced photocatalytic activity. We investigated the photocatalytic microbial sterilization of gram positive and gram negative bacteria, Escherichia coli, Salmonella typhimurium, and staphylococcus aureus. The microorganisms were treated with g-C3N4 (rod-type morphology) in 0.9% saline solution under visible light, and exhibited excellent photocatalytic sterilizing effect within 2 hours as compared to the reference sample (g-C3N4 of no specific morphology).

한-중 사드 분쟁이 제주 크루즈 시장에 미치는 영향에 관한 연구

허윤석,신범수 한국해양비즈니스학회 2018 해양비즈니스 Vol.- No.41

Jeju Cruise market is the fastest growing market in the world. The growth of the Jeju cruise market is linked to the growth of the Northeast Asia cruise market centered on China. Jeju has advantages such as the status of international free city, various tourist products, and geographical advantages. And these advantages have affected the growth and expansion of the cruise market. It also contributed to the revitalization of the local economy. After the THADD dispute with China in March 2017, however, the cruise market in Jeju, which has a market structure centered on China, was in a great crisis. The market situation has not as yet improved, and it is expected to continue for the time being. Therefore, it is urgent to establish measures to reduce dependence on China and create new demands in the market. This study suggests market diversification strategies to enhance the competitiveness of the Jeju cruise market.

제주도 크루즈 수용태세 변화에 관한 연구

허윤석,여영준 한국해양비즈니스학회 2019 해양비즈니스 Vol.- No.44

This study has been carried out in order to prepare countermeasures of Jeju cruise industry faced with the crisis. Jeju island has become the most visited port of call for cruise ships around the world and also the center for the growth of the Asia cruise industry. After the THAAD between Korea and China in 2017, however, Jeju cruise industry encountered unexpected hardship and it is still in an irreparable situation. Thus, it is urgent to establish strategies for enhancing its competitiveness in Jeju cruise industry. These strategies are, in particular, necessary to prepare for the sides of hardware and software in case the market recovers. In terms of hardware, a new harbor in Jeju should be constructed first. It is important to obtain additional berths in the Jeju port in order to react to rapidly changing consumer demands, and it is expected to facilitate the development of the new port in Jeju. In the side of software, the local government should develop political frameworks for the improvement in the immigration system by reforming and unifying cruise-related laws. Based on this, it is required to create more Jeju tour packages for revitalizing the local economy.

Effect of diluent on succinic acid extraction from artificial solution and fermentation broth

허윤석,전영시,홍연기,홍태희,홍원희 한국공업화학회 2004 한국공업화학회 연구논문 초록집 Vol.2004 No.1

사이버전쟁이 해상운송에 미치는 영향에 관한 연구

허윤석,주세환 경남대학교 산업경영연구소 2021 지역산업연구 Vol.44 No.4

As IT and OT, which were not closely related in the past, are connected to each other and connected to the Internet, functions such as engine efficiency monitoring, ship maintenance and spare parts management, unloading, gear, pump, cargo handling management, and optimal route monitoring are implemented. As a result, the possibility of cyber risk reaching OT on board via IT increases. It anticipates the situation when the system on board was indirectly affected by such an attack, although it was not the target of the cyber attack. It is rare for a vessel to be recognizable as having been subjected to a cyber attack, except when a claim for ransom was made by being targeted. Generally, crew members will perceive many things as irrationalities and failures of simple systems. If a malfunction is caused by infection of some systems by malware attack, it may be an infection damage caused by a cyber attack. It is not difficult to predict that some of the infections will infect other systems on board the ship, and the infection will spread to more and more connected terrestrial systems. If any failure is discovered, the system will try to restart onboard the ship. Depending on the situation, the manufacturer and service provider will be contacted to review recovery measures. Therefore, if crew members, manufacturers, or service providers do not have deep knowledge of cyber risks and easily implement recovery measures such as restarting and changing system settings, there is a possibility of further increasing the damage. It may affect the increasingly connected onshore headquarters and third-party systems. This study analyzes the current state of cyber war and the types of cyber attacks on ships, and considers countermeasures in case of cyber attacks based on this. 과거 서로 밀접하지 않았던 IT와 OT가 연결되고 디지털화가 진행됨에 따라서 선상에서의 활동들도 네트워크 기반 시스템을 통해 관리되기 시작하였다. 그 결과 생산성 향상의 결과를 도출하였으나 IT시스템으로 침투하여 본선 OT에 직접 영향을 미치는 사이버 공격 등에 대한 문제들과 피해들이 점차 증가하기 시작하였다. 선박을 표적으로 하여 실제로 나포되는 경우와 천재지변 등을 제외한 외부적인 환경 요인들로 발생한 피해는 선원들도 쉽게 인식하지 못하는 경우가 대부분이며, 이 경우 승조원들은 단순한 시스템 불합리 또는 고장 등으로 인식하고 있다. 일부 시스템이 밀웨어(malware)에 의해감염되어 이상이 발생하면 이것은 사이버 공격에 의한 감염 피해라 할 수 있으며, 그 일부의 감염이 본선 네트워크를 통해 다른 시스템, 더 나아가 항해 및 접속되고 있는 육상의 본사와 제3 자의 시스템까지도 영향을 미칠 수 있다. 본 연구에서는 해상 운송에 있어 최근 급증하고 있는 사이버 공격에 대한 현황들을 분석하고, 이를 바탕으로 효과적인 대응 방안을 고찰해 보고자 한다.

2P-761 Cesium-induced Inhibition of Bacterial Growth of Pseudomonas aeruginosa PAO1 and Their Possible Potential Applications for Bioremediation of Wastewater

허윤석,강성민,허남수,오서영,( Muruganantham Rethinasabapathy ),( A. T. Ezhil Vilian ),한영규 한국공업화학회 2017 한국공업화학회 연구논문 초록집 Vol.2017 No.1

This study examined the toxicity and accumulation behavior of cesium towards P. aeruginosa PAO1 and its capacity to remove cesium from waste water. The toxicity of P. aeruginosa PAO1 increases as the concentration of cesium is increased in concentration-dependent manner. P. aeruginosa PAO1 shows excellent Cs removal efficiency of 76.1% from the contaminated water. The toxicity of cesium on the cell wall and in the cytoplasm were studied by transmission electron microscopy and electron dispersive X-ray analysis. Finally, the removal of cesium from wastewater using P. aeruginosa PAO1 as a potential biosorbent and the blocking of competitive interactions of other monovalent cation, such as potassium, were assessed. Overall, P. aeruginosa PAO1 can be used as a high efficient biomaterial in the field of radioactive waste disposal and management.

Chaotic Dynamics of a Chua’s System with Voltage Controllability

허윤석,정진우,김지만,조문규,송한정 한국물리학회 2012 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.60 No.7

This paper presents an integrated circuit oriented Chua’s chaotic system with voltage controllability. The proposed chaotic system consists of an OTA (Operational Transconductance Amplifier)-based ground inductor, two passive capacitors, a MOS (Metal-Oxide-Semiconductor)-based active resistor and an OTA-based Chua’s diode with negative nonlinearity. A SPICE (Simulation Program with Integrated Circuit Emphasis) circuit analysis using 0.5-μm CMOS (Complementary Metal-Oxide-Semiconductor) process parameters was performed for the chaotic dynamics, such as the time waveform and the attractor plot. We confirmed that the chaotic behaviors of the system could be controlled by using the gate voltage of the MOS-based active resistor. Also, various chaotic dynamics of the circuit were analyzed for various MOS sizes of the OTA in the Chua’s diode.

Selectivity in the extraction of Acetic acid and Succinic acid from their binary solutions and fermentation broth

허윤석,홍연기,전영시,김도윤,이상엽,홍원희 한국화학공학회 2007 화학공학의이론과응용 Vol.10 No.1

최근 숙신산의 제약, 식품, 화장품 등의 산업적 용용 및 그 수요가 증가하면서 숙신산의 발효에 의한 생산방법연구가 진행되고 있다. 그러나 발효를 통한 숙신산 생산의 문제점은 발효 부산물에 의해 숙신산의 수율이 저하되고 숙신산의 순수한 정제공정이 필요하다는 점이다. 따라서 본 연구에서는 발효조에서 생성물에 혼합된 아세트산에 대한 숙신산의 선택적인 분리를 위해서 반응추출법을 이용하였다. 반응추출을 위해 3차 아민을 희석제에 용해시킨 유기상을 이용하여 숙신신과 아세트산의 혼합액과 실제 발효액에 동시에 적용하여 실험하였다. 동시에 pH에 따른 숙신산과 아세트산의 서로 다른 거동을 이용하여 숙신산/아세트산 수용액으로부터 아세트산을 선택적으로 분리하였다.

Delayed Infarction of Medullar and Cerebellum 3 Months after Vertebral Artery Injury with C1-2 Fracture: Case Report

허윤석,강석형,Ilhom Abdullaev,김노아 대한신경손상학회 2017 Korean Journal of Neurotrauma Vol.13 No.1

The clinical manifestations of vertebral artery (VA) injury (VAI) after cervical trauma range from asymptomatic to fatal cerebral infarction. Thrombotic occlusion and embolization to the distal arteries can cause cerebellar and brain stem infarction within days after trauma. We report a 64-year-old man who underwent arthrodesis surgery for C1 and C2 fractures. He had left VAI at the C2 transverse foramen site but was asymptomatic. The patient experiences brainstem and cerebellar infarction 3 months after injury to the VA, and we are here to discuss the treatment of VAI after cervical trauma