Analysis of a Building Structure with Added Viscoelastic Dampers

Lee Dong Guen,Hong Sung Il,Kim Jin Koo 한국지진공학회 1998 한국지진공학회논문집 Vol.2 No.3

Steel structures with added viscoelastic dampers are analysed to investigat their behavior under earthquake excitation. The direct integration method, which produces exact solution for the non-proportional or non-classical damping system, is used throughout the analysis. The results from modal strain energy method are also provided for comparison. Then a new analytical a, pp.oach, based on the rigid floor diaphragm assumption and matrix condensation technique, is introduced, and the results are compared with those obtained from direct integration method and modal strain energy method. The well known phenomenon, that the effectiveness of the viscoelastic dampers depends greatly on the location of the dampers, is once again confirmed in the analysis. It is also found that the modal strain energy method generaly underestimates the responses obtained from the direct integration method, especially when the dampers are placed in only a part of the building. The proposed method turns out to be very efficient with considerable saving in computation this and reasonably accurate considering the reduced degrees of freedom.

Phage Types and Pulsed-Field Gel Electrophoresis Patterns of Salmonella enterica serovar Enteritidis Isolated from Humans and Chickens

Sung Hun Kim,Shukho Kim,Sung Guen Chun,Mi-Sun Park,박정현,Bok-Kwon Lee 한국미생물학회 2008 The journal of microbiology Vol.46 No.2

We analyzed 66 Salmonella Enteritidis isolates in 2002. Thirty isolates were obtained from human patients with diarrhea, and 36 were obtained from chickens. A total of ten phage types (PT) were identified in the human and chicken isolates. PT1 and PT21 were the predominant PTs in both the human (20% and 13%) and chicken (17% and 47%) isolates. Twelve pulsotypes were generated by PFGE and divided into two major groups. Most of the PFGE types were categorized into cluster group 1. Eighteen chicken isolates in cluster group 1 showed high-level genetic association (>95%) with 22 other human isolates. Additionally, six chicken isolates from cluster group 2 showed fairly high-level genetic association (>95%) with the other seven human isolates. The highest levels of genetic association in humans and chickens were seen with A5-PT21 (11 isolates), A2-PT1 (7 isolates), and B1-PT4 (6 isolates). The Pulsed-Field Gel Electrophoresis (PFGE) and phage typing provided conclusive evidence that human Salmonella infections are attributable to the consumption of contaminated chicken.

Impact of Family History of Cancer on Development of Lung Cancer Among the Korean Population: A Prospective Cohort Study Using KoGES Data

( Sang Hyuk Kim ),( Hyun Lee ),( Bo-guen Kim ),( Sang-heon Kim ),( Jang Won Sohn ),( Ho Joo Yoon ),( Dong Won Park ) 대한결핵 및 호흡기학회 2023 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.136 No.0

High-Performance Sensorless Control of PSM Using Back-EMF and Reactive Power

Guen Bo Lee,Jun Seong Park,Sung Hun Lee,Young Ahn Kwon 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8

This Paper investigates a high-performance strategy for speed sensorless control of a permanent magnet synchronous motor. Two speed sensorless controls using back-뜰 뭉 reactive power are analyzed in this paper, and these two speed estimations are appropriately applied according to the steady and transient states for a high-performance sensorless control. The proposed sensorless control algorithm has a better performance compared to the conventional control algorithms.

Characteristics of flux and gel layer on microfilter and non-woven fabric filter surface based on anoxic-aerobic MBRs.

Lee, Jung-Yeol,Choi, Bo-Kyung,Ahn, Kyu-Hong,Maeng, Sung Kyu,Song, Kyung-Guen Springer-Verlag 2012 BIOPROCESS AND BIOSYSTEMS ENGINEERING Vol.35 No.8

<P>Non-woven fabric filter- (NWFF) and microfilter-MBR modules were made using 100?μm polypropylene and 0.25?μm polyethylene materials, respectively. The performances and mechanisms of the two processes were investigated, including additional batch filtration tests to find the function of the dynamic gel layer on the membrane surface. The HRT of both MBRs was 9?h and the operating permeate flux was 13?L/m(2)/h. The two MBRs consisted of an anoxic and aerobic reactor. The NWFF or microfilter (MF) was submerged in each of the aerobic reactors. The two MBRs showed similar performances for the removal of organic matters, suspended solids and nitrogen. Cake formation on the NWFF contributed to major resistance, while the gel layer on the microfilter or internal fouling of the pores played a key role in the fouling of the membrane surface. The amount of soluble extracellular polymer substances (EPS) (13?mg/L) of the attached sludge on the NWFF surface was larger than that (11?mg/L) of that suspended sludge. Consequently, the functional gel layer for the coarse and microfilter is established based on the relationship among the EPS, transmembrane pressure and MLSS.</P>

The Effect of the Changes in Wind Velocity and Slope on Forest Fire Behavior in Pinus densiflora Stands

Sung Yong Kim,Hee Young Ahn,Chun Guen Kwon,Byung Doo Lee 위기관리 이론과 실천 2016 Crisisonomy Vol.12 No.11

본 연구에서는 단순 물리적 연소실험을 통하여 경사와 풍속 변화가 산불행동 특성 변화에 어떠한 영향을 미치는지를 파악하고자 하였다. 경사는 상향경사와 하향경사 조건을 모두 고려하였고, 풍속은 0m/s, 2m/s, 4m/s, 6m/s의 조건을 부여하여 실험하였다. 본 연구 결과에 의하면, 상향경사가 크고, 풍속이 빠를수록 화염의 온도가 지속적으로 증가하여 최대 1,353.3°C까지 높아지는 것으로 나타났다. 확산속도의 경우에는 경사 30°, 6m/s의 풍속에서 최대 분당 15m까지 빨라지는 현상을 관찰하였다. 조건에 따른 산불화염의 강도 추정에서는 최소 78.11kW/m∼최대 5,982.23kW/m의 범위로 나타났으며, 경사가 크고, 풍속이 강해질수록 확산강도가 높아지는 패턴으로 수치의 범위가 국외에서 제시한 연구결과와 유사하였다. 본 연구의 결과는 추후 산불확산 및 강도를 정확하게 예측하는 데 유용한 정보로 활용될 것이다. The objective of this study is to find out what effects the changes in slope and wind velocity has on characteristic changes in fire behavior through a simple burning experiment. Both upslope and downslope were considered for slope factor and the conditions of 0m/s, 2m/s, 4m/s and 6m/s were applied for wind velocity factor. The result of this study shows that, with the higher upslope and wind velocity, the flame temperature continues to increase up to 1,353.3°C. The rate of spread was also found to be as fast as 15m/min in the condition of 30° slope and 6m/s wind velocity. The conditional fire intensity was estimated to range from 78.11 kW/m to 5,982.23 kW/m and also increased with the higher slope and wind velocity, which was similar to findings in the literature for other countries. The result of this study will help to predict accurately the spread and intensity of forest fire.

Development and Performance Evaluation of Environmentally Safe Foam Agents for Wildfire

Sung Yong Kim,Hee Young Ahn,Won Ho Cho,Jae Seong Lee,Chun Guen Kwon,Byung Doo Lee 위기관리 이론과 실천 2016 Crisisonomy Vol.12 No.11

본 연구에서는 천연계면활성제 조성물 등을 이용하여 환경친화적이고, 소화성능이 우수한 포 소화약제를 개발하고, 기초물성, 친환경성, 소화성능 평가를 실시하였다. 개발된 소화약제는 국민안전처 기준에 따라 기초물성을 실험하고, 물벼룩과 지렁이 독성으로 친환경성을 평가하였다. 소화성능실험은 자체적으로 개발한 산불진화용 성능시험기를 이용해 실시하였다. 그 결과, 기초물성의 경우변질 전, 후 실험에서 모두 포 소화약제로서 요구되는 물성을 모두 만족하였다. 물벼룩 독성 실험에서는 포 소화약제 48.854mg/L 이하에서 반수유영저해 현상이 발생하지 않았고, 지렁이 독성의 실험에서는 포 소화약제 1,000mg/kg 조건에서도 치사에 영향을 미치는 요인이 발생하지 않아 두 실험모두 친환경성 기준에 만족하였다. 소화성능 실험은 물에 비해 1.6배 이상 성능이 우수한 것으로나타났다. This study aims at developing environmentally friendly foaming agents with high fire-fighting performance by using natural surfactant compositions, and evaluating its basic property, environmental friendliness and extinguishing performance. The basic property test was carried out on the newly-developed agent in accordance with standards outlined by the Ministry of Public Safety and Security in Korea. As for environmental friendliness, the toxicity tests were conducted with water fleas and earthworms. An independently developed device testing wildfire suppression performance was used to assess extinguishing capability. The results showed the foaming agent met all required properties in both experiments before and after the property change. In the toxicity test on water fleas, immobilization occurred with 48.854mg/l foaming agent, but in the test on earthworms, even the 1,000mg/kg foaming agent did not cause any fatal effect. Its extinguishing performance was found to be 1.6 times greater than water.

Isolation and identification of Vibrio harveyi from chub mackerel (Scomber japonicus)

Lee, Young-Ran,Jun, Jin-Woo,Giri, Sib Sankar,Kim, Hyoun-Joong,Yun, Sae-Kil,Chi, Cheng,Kim, Sang-Guen,Koh, Jeong-Rack,Jung, Ji-Yun,Park, Se Chang The Korean Society of Veterinary Science 2016 大韓獸醫學會誌 Vol.56 No.1

For several days, there was a series of mortalities of chub mackerel (Scomber japonicus) that were reared for public exhibition in a private aquarium in Seoul, Korea. As part of the diagnosis of the dead fish, a bacterial isolate from the kidney was cultured, identified, and confirmed to be Vibrio (V.) harveyi using Vitek System 2 and 16S rRNA gene sequencing. Phylogenetic analysis was also performed by the neighbor-joining method. As a result, the V. harveyi isolated from chub mackerels of a private aquarium in Korea, called as SNUVh-LW1, was clustered in the same group with V. harveyi ATCC33843.

The Secondary Products by Ozone-initiated Reaction with Terpenes Emitted from Natural Paint : 천연 페인트로부터 방출되는 털핀류와 오존 반응에 의한 이차 오염물질 생성

Sang-Guen Jung(정상근),Rheo B. Lamorena, Woo Jin Lee(이우진),Gwi-Nam Bae(배귀남),Kil-Choo Moon(문길주),Shin-Do Kim(김신도) 한국실내환경학회 2004 한국실내환경학회지 Vol.1 No.1

입자, 알데히드류, 케톤 같은 유해한 휘발성 유기화합물들이 생성된다는 보고가 있었다. 이번 연구에서는 천연 페인트에서 방출되는 털핀과 오존의 반응에 의한 미세 입자와 이차 유기화합물 생성에 대해서 조사하였다. 시편에 페인트를 칠하여 실내에서 건조시킨 후 테플론 챔버 내에서 오존과 반응시켰다. α, β-파이닌은 GC-MS와 FTIR을 사용하여 정성하였다. 입자생성에 대한 오존의 영향을 조사하기 위해 여러가지 실험이 수행되었다. 오존 농도가 100ppb에서 1000ppb로 증가할 때 입자 수농도는 8,000에서 70,000 particles/㎤까지 증가하였다. 포름알데하이드, 아세트알데하이드, 아세톤+아크로레인, 프로피온알데하이드 등의 반응 생성물은 HPLC로 분석하였다. 이런 화합물들은 잠재적으로 유해한 화합물이고, 인체에 해로운 영향을 끼친다. 이번 연구결과는 친환경제품의 실내공기질에 대한 해로운 영향에 대한 보기를 보여주었다. The use of natural paint for the application to walls and furnishings is now increasing to improve indoor air quality, thereby the natural paint could be a significant source of biogenic volatile organic compounds (BVOCs) in indoor environments. Recent studies have shown that gas-phase reactions between terpenes and ozone can generate sub-micron size particles and toxic volatile organic compounds such as aldehydes and ketones. In this research, we have studied the formation of particles and secondary organic compounds during the reaction of ozone with terpenes emitted from commercial natural paint. The paint applied onto stainless steel was dried and oxidized in a teflon chamber. Two monoterpenes (α- and β-pinenes) were identified by FTIR and GC/MS. Several tests were performed to evaluate the effects of ozone concentration on particle formation. Increased ozone levels significantly affect the increase of particle number concentration (monitored with SMPS), which results in the increase of particle counts ranging from 8,000 to 70,000 particles/㎤. Gas-phase products such as formaldehyde, acetaldehyde, acetone + acrolein, and propionaldehyde were identified during the terpene/ozone reactions by HPLC. These compounds are potential hazardous chemical compounds having harmful health effects to animals and plants. The results obtained from this study provide an insight on the adverse effect of eco-friendly natural product on indoor air quality (IAQ).

An efficient modeling technique for floor vibration in multi-story buildings

Lee, Dong-Guen,Ahn, Sang-Kyoung,Kim, Jinkoo Techno-Press 2000 Structural Engineering and Mechanics, An Int'l Jou Vol.10 No.6

Analysis of a framed structure for vertical vibration requires a lot of computational efforts because large number of degrees of freedom are generally involved in the dynamic responses. This paper presents an efficient modeling technique for vertical vibration utilizing substructuring technique and super elements. To simplify the modeling procedure each floor in a structure is modeled as a substructure. Only the vertical translational degrees of freedom are selected as master degrees of freedom in the inside of each substructure. At the substructure-column interface, horizontal and rotational degrees of freedom are also included considering the compatibility condition of slabs and columns. For further simplification, the repeated parts in a substructure are modeled as super elements, which reduces computation time required for the construction of system matrices in a substructure. Finally, the Guyan reduction technique is applied to enhance the efficiency of dynamic analysis. In numerical examples, the efficiency and accuracy of the proposed method are demonstrated by comparing the response time histories and the analysis time.