청각 자극용 전기자극기 개발

허승덕,정동근,김리석,김광년,강명구,김재룡,김기련 한국음성과학회 2004 음성과학 Vol.11 No.3

This paper introduces a development of an electrical stimulator for auditory stimulation. The electrical stimulator is useful in neurotological diagnosis, audiological evaluation, candidate selection for cochlear implantation, optimal device selection and decision making of MAP strategy for severe-to-profound hearing impaired persons. The development was based on sound parameters of auditory brainstem responses and auditory electrophysiological characteristic such as effective firing of auditory nerve and recording evoked potentials during refractory period of neuron. Besides pulse parameter could adjustable by programming for more varied electrical stimulation evoked response audiometry. Using the electrical stimulator, electrical square pulse was applied to promontory, and electrically evoked auditory brainstem response and electrically middle latency response were successfully recorded in cats.

팔당호의 생태학적 수질환경의 변화와 미생물 분포

허성남,민경희,유재근,최순영 숙명여자대학교 자연과학연구소 1999 자연과학논문집 Vol.- No.10

팔당호의 생태학적 환경요인의 계절적인 변화를 분석하므로서 이것으로 인한 식물성 플랑크톤의 연관성을 고찰과 함께 오염과정을 파악하여 수질오염의 예방의 기초자료를 얻고자 본 실험을 수행하였다. 1994년 4월부터 1995년 10월까지 계절별로 3개 지점에서 시료를 채취하여 표층부와 저층부의 수질을 분석하였다 용존산소(DO)와 pH는 각각 7.0-11.6 ㎎/ℓ와 6.9-8.9의 범위이었으며 COD와 BOD농도는 각각 1.6-4.8 ㎎/ℓ와 0.8-2.9 ㎎/ℓ이었으며,SS는 1.8-8.6 ㎎/ℓ의 농도차를 보여 주었다. 또한 NH₃-N와 PO₄-P의 농도는 각각 0.161-0.478 ㎎/ℓ와 0.003-0.073 ㎎/ℓ이었다. 표층의 chlorophyll a의 농도는 낮게는 북한강 유입부위인 12.3 ㎎/ℓ로부터 가장 높은 경안천 유입부위 23.8 ㎎/ℓ의 범위를 보여주고 있다. pH,전도도, COD, BOD, SS ,총인, chlorophyll a의 농도는 하계절에 가장 높았으며 이 결과로 미루어 보아 하계절에는 하천에 오염물질이 가장 많이 유입되는 것으로 추정된다. Station별로 조사한 결과 이들의 농도는 경안천 하류인 St. 3가 남한강 하류인 St. 2이나 댐지역의 St. 4보다 높은 결과를 보여 주었으므로 경안천 상류에서 오염원이 가장 많이 유입되는 것으로 추정된다. 아울러 종속영양세균의 분포도 경안천이 다른 지역보다 가장 높게 나타났다. Seasonal variation of water quality was examined in the reservoir, lake Paldang on Han River, the inlet stations from three rivers, North Han River, South Han liver, Kyung-An stream, and the station of dam area of the lake. Water samples were collected bimonthly from surface and bottom layers at four different stations of the lake Paldang from April 1993 to August 1994. With respect to the seasonal variation, pH, conductivity, and concentrations of COD, BOD, SS, total phosphorus, and chlorophyll a were higher in summer compared with those of autumn or other seasons, while concentrations of DO, NH₃-N, and PO₄-P were increased in winter. Concentrations of COD, BOD, chlorophyll a, total nitrogen and phosphorus were the highest at the station of Kyung-An stream rather than those of other three stations. The average concentrations of chlorophyll a surface water were from 12.3 ㎎/ℓ at North Han River to 23.8 ㎎/ℓ at Kyung-An stream. Heterotrophic bacterial distribution showed higher at the station of Kyung-An steam than those of South Han River and the dam station of the lake.

Maintenance Priority Index of Overhead Transmission Lines for Reliability Centered Approach

Jae-Haeng Heo,Mun-Kyeom Kim,Dam Kim,Jae-Kun Lyu,Yong-Cheol Kang,Jong-Keun Park 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

Overhead transmission lines are crucial components in power transmission systems. Welldesigned maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

Maintenance Priority Index of Overhead Transmission Lines for Reliability Centered Approach

Heo, Jae-Haeng,Kim, Mun-Kyeom,Kim, Dam,Lyu, Jae-Kun,Kang, Yong-Cheol,Park, Jong-Keun The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.4

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

Application of Particle Swarm Optimization to the Reliability Centered Maintenance Method for Transmission Systems

Heo, Jae-Haeng,Lyu, Jae-Kun,Kim, Mun-Kyeom,Park, Jong-Keun The Korean Institute of Electrical Engineers 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.

Application of Particle Swarm Optimization to the Reliability Centered Maintenance Method for Transmission Systems

Jae-Haeng Heo,Jae-Kun Lyu,Mun-Kyeom Kim,Jong-Keun Park 대한전기학회 2012 Journal of Electrical Engineering & Technology Vol.7 No.6

Electric power transmission utilities make an effort to maximize profit by reducing their electricity supply and operation costs while maintaining their reliability. The development of maintenance strategies for aged components is one of the more effective ways to achieve this goal. The reliability centered approach is a key method in providing optimal maintenance strategies. It considers the tradeoffs between the upfront maintenance costs and the potential costs incurred by reliability losses. This paper discusses the application of the Particle Swarm Optimization (PSO) technique used to find the optimal maintenance strategy for a transmission component in order to achieve the minimum total expected cost composed of Generation Cost (GC), Maintenance Cost (MC), Repair Cost (RC) and Outage Cost (OC). Three components of a transmission system are considered: overhead lines, underground cables and insulators are considered. In regards to aged and aging component, a component state model that uses a modified Markov chain is proposed. A simulation has been performed on an IEEE 9-bus system. The results from this simulation are quite encouraging, and then the proposed approach will be useful in practical maintenance scheduling.

Effect of Bacillus subtilis S37-2 on Microorganisms in Soil and Growth of Lettuce (Lactuca sativa)

Jae-Young Heo,Dae-Ho Kim,Yong-Jo Choi,Sang-Dae Lee,Su-Won Seuk,Jae-Kyeong Song,Jang-Sik Kwon,Min-Keun Kim 한국토양비료학회 2016 한국토양비료학회지 Vol.49 No.5

The present study evaluated the variations in soil microbial population of controlled horticultural land used for lettuce (Lactuca sativa) cultivation by their fatty acid methyl ester and chemical properties. We utilized four treatment groups, no treatment (NT), culture medium (CM), Bacillus subtilis S37-2 (KACC 91281P) × 10<SUP>6</SUP> CFU mL<SUP>-1</SUP>(BS1), and Bacillus subtilis S37-2 × 10<SUP>7</SUP> CFU mL-1(BS2) and analyzed these variations throughout the before treatment and harvesting stage. The chemical properties such as pH, organic matter, available phosphate, and electrical conductivity in soils before treatment and harvesting stage showed no significant difference among the treatments. Total numbers of bacteria and microbial biomass C in soil treated with BS1 were larger than those of NT, CM, and BS2, whereas total number of fungi at the harvesting stage was significantly lower in the BS1 soil than in the NT and CM soils (P < 0.05). On basis of leaf length, leaf width, leaf number and leaf weight, the growth characteristics lettuce on the soil treated with BS1 and BS2 was faster than those of NT and CM soils. Yield of lettuce with treated BS1 and BS2 were 35% and 29% more than that of NT, respectively.

Changes in High-Density Lipoprotein Cholesterol and Risks of Cardiovascular Events: A Post Hoc Analysis from the PICASSO Trial

Eun-Jae Lee,Sun U. Kwon,Jong-Ho Park,Yong-Jae Kim,Keun-Sik Hong,Sungwook Yu,Yang-Ha Hwang,Ji Sung Lee,Juneyoung Lee,Joung-Ho Rha,Sung Hyuk Heo,Sung Hwan Ahn,Woo-Keun Seo,Jong-Moo Park,Ju-Hun Lee,Jee-H 대한뇌졸중학회 2020 Journal of stroke Vol.22 No.1

Background and purpose Whether pharmacologically altered high-density lipoprotein cholesterol (HDL-C) affects the risk of cardiovascular events is unknown. Recently, we have reported the Prevention of Cardiovascular Events in Asian Patients with Ischaemic Stroke at High Risk of Cerebral Haemorrhage (PICASSO) trial that demonstrated the non-inferiority of cilostazol to aspirin and superiority of probucol to non-probucol for cardiovascular prevention in ischemic stroke patients (clinicaltrials.gov: NCT01013532). We aimed to determine whether on-treatment HDL-C changes by cilostazol and probucol influence the treatment effect of each study medication during the PICASSO study. Methods Of the 1,534 randomized patients, 1,373 (89.5%) with baseline cholesterol parameters were analyzed. Efficacy endpoint was the composite of stroke, myocardial infarction, and cardiovascular death. Cox proportional hazards regression analysis examined an interaction between the treatment effect and changes in HDL-C levels from randomization to 1 month for each study arm. Results One-month post-randomization mean HDL-C level was significantly higher in the cilostazol group than in the aspirin group (1.08 mmol/L vs. 1.00 mmol/L, P<0.001). The mean HDL-C level was significantly lower in the probucol group than in the non-probucol group (0.86 mmol/L vs. 1.22 mmol/L, P<0.001). These trends persisted throughout the study. In both study arms, no significant interaction was observed between HDL-C changes and the assigned treatment regarding the risk of the efficacy endpoint. Conclusions Despite significant HDL-C changes, the effects of cilostazol and probucol treatment on the risk of cardiovascular events were insignificant. Pharmacologically altered HDL-C levels may not be reliable prognostic markers for cardiovascular risk.

분산전원을 포함한 배전계통에서 설치비용과 유지보수 비용을 고려한 병렬 캐패시터-리액터 Bank의 최적 설치 위치 선정

허재행(Jae-Haeng Heo),류재근(Jae-Kun Lyu),이우리(Woo-Ri Lee),박종영(Jong-Young Park),박종근(Jong-Keun Park) 대한전기학회 2013 전기학회논문지 Vol.62 No.11

This paper proposes the allocation method for capacitor-reactor banks in a distribution system with dispersed generators to reduce the installation costs, the maintenance costs and minimize the loss of electrical energy. The expected lifetime and maintenance period of devices with moving parts depends on the total number of operations, which affects the replacement and maintenance period for aging equipment under a limited budget. In this paper, the expected device lifetimes and the maintenance period are included in the formulation, and the optimal operation status of the devices is determined using a genetic algorithm. The optimal numbers and locations for capacitor-reactor banks are determined based on the optimal operation status. Simulation results in a 69-bus distribution system with the dispersed generator show that the proposed technique performs better than conventional methods.

시설상추에 대한 Bacillus subtilis S37-2의 처리효과

허재영(Jae-Young Heo),이영한(Young Han Lee),김민근(Min-keun Kim),송재경(Jae-Kyeong Song),권장식(Jang-Sik Kwoon),김대호(Dae-Ho Kim),최용조(Yong-Jo Choi),이상대(Sang-Dae Lee) 한국토양비료학회 2016 한국토양비료학회 학술발표회 초록집 Vol.2016 No.3