• Title/Summary/Keyword: 건물적용

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Derivation of Dynamic Characteristic Values for Multi-degree-of-freedom Frame Structures based on Frequency Response Function(FRF) (주파수응답함수 기반 다자유도 골조 구조물의 동특성치 도출 및 구조모델링 적용 )

  • So-Yeon Kim;Min-Young Kim;Seung-Jae Lee;Kyoung-Kyu Choi
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.4
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    • pp.1-10
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    • 2023
  • In the seismic design of structures, seismic forces are calculated based on structural models and analysis. In order to accurately address the dynamic characteristics of the actual structure in the structural model, calibration based on actual measurements is required. In this study, a 4-story frame test specimen was manufactured to simulate frame building, accelerometers were attached at each floor, and 1-axis shaking table test was performed. The natural period of the specimen was similar to that of the actual 4 story frame building, and the columns were designed to behave with double-curvature having the infinite stiffness of the horizontal members. To investigate the effects seismic waves characteristics, historical and artificial excitations with various frequencies and acceleration magnitudes were applied. The natural frequencies, damping ratios, and mode shapes were obtained using frequency response functions obtained from dynamic response signals, and the mode vector deviations according to the input seismic waves were verified using the Mode assurance criterion (MAC). In addition, the damping ratios obtained from the vibration tests were applied to the structural model, and the method with refined dynamic characteristics was validated by comparing the analysis results with the experimental data.

Design and Implementation of Economical Smart Wall Switch with IEEE 802.11b/g/n

  • Myeong-Chul Park;Hyoun-Chul Choi;Cha-Hun Park
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.8
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    • pp.103-109
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    • 2023
  • In this paper, we propose a smart wall switch based on IEEE 802.11b/g/n standard 2.4GHz band communication. As the 4th industrial era evolves, smart home solution development is actively underway, and application cases for smart wall switches are increasing. Most of the Chinese products that preoccupy the market through price competitiveness use Bluetooth and Zigbee communication switches. However, while ZigBee communication is low power, communication speed is slower than Bluetooth and network configuration through a separate hub is additionally required. The Bluetooth method has problems in that the communication range and speed are lower than Wi-Fi communication, the communication standby time is relatively long, and security is weak. In this study, an IEEE 802.11b/g/n smart wall switch applied with Wi-Fi communication technology was developed. In addition, through the two-wire structure, it is designed so that no additional cost is incurred through the construction of a separate neutral line in the building. The result of the study is more than 30% cheaper than the existing wall switch, so it is judged that it will be able to preoccupy the market not only in terms of technological competitiveness but also price competitiveness.

Evaluation of Performance of Grouts and Pipe Sections for Closed-loop Vertical Ground Heat Exchanger by In-situ Thermal Response Test (현장 열응답 시험을 통한 수직 밀폐형 지중열교환기용 그라우트와 열교환 파이프 단면의 성능 평가)

  • Lee, Chul-Ho;Park, Moon-Seo;Min, Sun-Hong;Choi, Hang-Seok;Sohn, Byong-Hu
    • Journal of the Korean Geotechnical Society
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    • v.26 no.7
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    • pp.93-106
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    • 2010
  • In performing a series of in-situ thermal response tests, the effective thermal conductivities of six vertical closed-loop ground heat exchangers were experimentally evaluated and compared one another, which were constructed in a test bed in Wonju. To compare thermal efficiency of the ground heat exchangers in field, the six boreholes were constructed with different construction conditions: grouting materials (cement vs. bentonite), different additives (silica sand vs. graphite) and the shape of pipe-sections (general U-loop type vs. 3 pipe-type). From the test results, it can be concluded that cement grouting has a higher effective thermal conductivity than bentonite grouting, and the efficiency of graphite better performs than silica sand as a thermally-enhancing addictive. In addition, a new 3 pipe-type heat exchanger provides less thermal interference between the inlet and outlet pipe than the conventional U-loop type heat exchanger, which results in superior thermal performance. Based on the results from the in-situ thermal response tests, a series of economic analyses have been made to show the applicability of the new addictives and 3 pipe-type heat exchanger.

Inelastic Dynamic Analysis of Structure Subjected to Across-Wind Load (풍직각방향 풍하중이 작용하는 구조물의 비탄성 동적 해석)

  • Ju-Won Kim
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.36 no.3
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    • pp.185-192
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    • 2023
  • In this study, fluctuating wind velocity for time history analysis is simulated by a single variate, single-dimensional random process using the KBC2022 spectrum about across-wind direction. This study analyzed and obtained the inelastic dynamic response for structures modeled as a single-degree-of-freedom system. It is assumed that the wind response is excellent in the primary mode, the change in vibration owing to plasticization is minor, along-wind vibration and across-wind vibration are independent, and the effect of torsional vibration is small. The numerical results, obtained by the Newmark-𝛽 method, shows the time-history responses and trends of maximum displacements. As a result of analyzing the inelastic dynamic response of the structure with the second stiffness ratio(𝛼) and yield displacement ratio (𝛽) as variables, it is identified that as the yield displacement ratio (𝛽) increases when the second stiffness ratio is constant, the maximum displacement ratio decreases, then reaches a minimum value, and then increases. When the stiffness ratio is greater than 0.5, there is a yield point ratio at which the maximum displacement ratio is less than 1, indicating that the maximum deformation is reduced compared to the elastically designed building even if the inelastic behavior is permitted in the inelastic wind design.

Exploring the Cognitive Factors that Affect Pedestrian-Vehicle Crashes in Seoul, Korea : Application of Deep Learning Semantic Segmentation (서울시 보행자 교통사고에 영향을 미치는 인지적 요인 분석 : 딥러닝 기반의 의미론적 분할기법을 적용하여)

  • Ko, Dong-Won;Park, Seung-Hoon;Lee, Chang-Woo
    • The Journal of the Korea Contents Association
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    • v.22 no.5
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    • pp.288-304
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    • 2022
  • Walking is an eco-friendly and sustainable means of transportation that promotes health and endurance. Despite the positive health benefits of walking, pedestrian safety is a serious problem in Korea. Therefore, it is necessary to investigate with various studies to reduce pedestrian-vehicle crashes. In this study, the cognitive characteristics affecting pedestrian-vehicle crashes were considered by applying deep learning semantic segmentation. The main results are as follows. First, it was found that the risk of pedestrian-vehicle crashes increased when the ratio of buildings among cognitive factors increased and when the ratio of vegetation and the ratio of sky decreased. Second, the humps were shown to reduce the risk of pedestrian-related collisions. Third, the risk of pedestrian-vehicle crashes was found to increase in areas with many neighborhood roads with lower hierarchy. Fourth, traffic lights, crosswalks, and traffic signs do not have a practical effect on reducing pedestrian-vehicle crashes. This study considered existing physical neighborhood environmental factors as well as factors in cognitive aspects that comprise the visual elements of the streetscape. In fact, the cognitive characteristics were shown to have an effect on the occurrence of pedestrian- related collisions. Therefore, it is expected that this study will be used as fundamental research to create a pedestrian-friendly urban environment considering cognitive characteristics in the future.

Assessment of Wave Change considering the Impact of Climate Change (기후변화 영향을 고려한 파랑 변화 평가)

  • Chang Kyum Kim;Ho Jin Lee;Sung Duk Kim;Byung Cheol Oh;Ji Eun Choi
    • Journal of Korean Society of Disaster and Security
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    • v.16 no.4
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    • pp.19-31
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    • 2023
  • According to the climate change scenarios, the intensity of typhoons, a major factor in Korea's natural disaster, is expected to increase. The increase in typhoon intensity leads to a rise in wave heights, which is likely to cause large-scale disasters in coastal regions with high populations and building density for dwelling, industry, and tourism. This study, therefore, analyzed observation data of the Donghae ocean data buoy and conducted a numerical model simulation for wave estimations for the typhoon MAYSAK (202009) period, which showed the maximum significant wave height. The boundary conditions for wave simulations were a JMA-MSM wind field and a wind field applying the typhoon central pressure reduction rate in the SSP5-8.5 climate change scenario. As a result of the wave simulations, the wave height in front of the breakwater at Sokcho port was increased by 15.27% from 4.06 m to 4.68 m in the SSP5-8.5 scenario. Furthermore, the return period at the location of 147-2 grid point of deep-sea design wave was calculated to increase at least twice, it is necessary to improve the deep-sea design wave of return period of 50-year, which is prescriptively applied when designing coastal structures.

Simulation of Soil Moisture in Gyeongan-cheon Watershed Using WEP Model (WEP 모형을 이용한 경안천 토양수분 모의)

  • Noh, Seong-Jin;Kim, Hyeon-Jun;Kim, Cheol-Gyeom;Jang, Cheol-Hee
    • Proceedings of the Korea Water Resources Association Conference
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    • 2006.05a
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    • pp.720-725
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    • 2006
  • 토양수분은 식물의 생장 및 가용수자원 산정 등에 있어서 중요한 요소로서 토양층 상부의 수 m내에 존재하는 수분의 양을 일컫는다. 토양수분과 토양수분의 공간적 시간적 특징들은 증발, 침투, 지하수 재충전, 토양침식, 식생 분포 등을 지배하는 중요한 요소이다. 강우 등으로 인한 지면과 지표하에서의 순간적인 포화공간의 형성 및 유출의 생성 등을 포함하는 과정과 증발산 등은 모두 비포화대(vadose zone) 혹은 토양층에서의 토양수분의 함량에 크게 의존하게 된다(이가영 등(2005)). 분포형 수문모형은 유역을 격자단위로 세분화하여 매개변수를 부여하고, 증발산, 침투, 지표면유출, 중간유출, 지하수유출, 하도 흐름 등 여러 가지 수문요소를 해석하는 종합적인 수문모형이다. 지표면에 내린 강우가 증발, 침투, 유출될 지는 토양수분의 함량에 크게 의존하게 되며, 따라서 토양수분에 대한 적절한 모의가 분포형 수문모형의 정확도를 좌우하는 핵심이라 할 수 있다. 본 연구에서는 분포형 수문모형인 WEP 모형을 경안천 유역(유역면적: $575km^2$, 유로연장: 49.3㎞)에 적용하여 토양수분의 시공간분포를 모의하였다. 지점별 토양수분 모의결과, 토양 매개변수의 최대, 최소값 내에서 적절히 모의됨을 확인하였으나, 관측값이 없어 실질적으로 타당한지 여부는 검증하지 못하였다. 토양수분비율, 연간 증발산량, 지표면 유출량 공간분포를 비교한 결과, 토양수분비율이 연간 증발산량 모의에 직접적인 영향을 주는 것을 확인할 수 있었다. 일부격자에서는 토양수분이 지나치게 높게 모의되었는데, 지하수위와 관련있는 것으로 보이며, 구축된 자료가 부족한 지하대수층에 대한 정보부족이 토양수분 계산에도 영향을 준 것으로 보인다. 본 연구는 WEP 모형의 토양수분 해석능력에 대한 시험적용에 그 의의가 있으며, 향후 토양 및 지표하 매개변수 정보가 충분히 갖추어지고, 토양수분 관측결과 있는 대상유역에 대한 적용이 요구된다.-Moment 방법에 의해 추정된 매개변수를 사용한 Power 분포를 적용하였으며 이들 분포의 적합도를 PPCC Test를 사용하여 평가해봄으로써 낙동강 유역에서의 저수시의 유출량 추정에 대한 Power 분포의 적용성을 판단해 보았다. 뿐만 아니라 이와 관련된 수문요소기술을 확보할 수 있을 것이다.역의 물순환 과정을 보다 명확히 규명하고자 노력하였다.으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주식시장에 적합한 거래전략은 반전거래전략이고, 이 전략의 유용성은 투자자가 설정한 투자기간보다 더욱 긴 분석기간의 주식가격정보에 의하여 최대한 발휘될 수 있음을 확인하였다.(M1), 무역적자의

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Effects of Supplementing Aqueous Direct-Fed Microbials on In Vitro Fermentation and Fibrolytic Enzyme Activity in the Ruminant Nutrition (반추가축영양에 있어서 액상미생물제제의 첨가가 In Vitro 발효성상과 섬유소분해효소활성에 미치는 영향)

  • Lee, S.H.;Seo, I.J.
    • Journal of Animal Science and Technology
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    • v.47 no.5
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    • pp.789-804
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    • 2005
  • This study was conducted to determine effects of supplementation levels of aqueous direct-fed microbials (DFM; Bacillus spp.) to TMR(exp. 1.) and aqueous DFM addition under the various ratios of starch and cellulose(exp. 2.) on ruminal fermentation and fibrolytic enzyme activity. In experiment 1, ruminal fluids taken from rumen-cannulated Holstein cows were incubated during 24 hr by using TMR as substrates. Aqueous DFM was applied at a rate of 0, 0.025 and 0.05%, respectively. The pH of 0.025% treatment was not significantly different from that of control at 6 and 9 hr, but it was significantly lower (P<0.05) than 0.05% treatment. Concentrations of ammonia-N and VFAs were not affected by supplementing aqueous DFM. The A:P ratio of 0.05% treatment was significantly increased(P<0.05) by supplementation of aqueous DFM as compared with that of control at 24 hr. Although overall fibrolytic enzyme activities were not significantly affected by supplementing aqueous DFM, CMCase(carboxymethylcellulase) activity showed significant increase(P<0.05) compared to control at 6hr. However, the xylanase activity of 0.05% treatment significantly decreased(P<0.05) at 12 hr due to the application of aqueous DFM. There was no significant difference for in vitro dry matter disappearance among treatments. In experiment 2, ruminal fluids were incubated under the condition of various ratios of starch to cellulose(90:10, 70:30, 50:50, 30:70 and 10:90) with or without aqueous DFM(0.025%). Ruminal pH was unaffected by the addition of aqueous DFM, however, as increased level of starch, ruminal pH partially showed significant decrease(P<0.05). Ammonia-N concentration was not affected by aqueous DFM and ratio of starch and cellulose. On 9 hr incubation, DFM addition at a ratio of 70:30 showed significantly (P<0.05) lower value of ammonia-N(35.65 mg/dL) than that(65.05 mg/dL) of control. Concentrations of VFAs were significantly increased(P<0.05) by aqueous DFM addition compared with control at the same ratio on 6 hr incubation. The overall CMCase activity was not affected by aqueous DFM addition. However, the xylanase activity by aqueous DFM partially showed significant differences at the ratios of 90:10, 30:70 and 10:90. Our results indicated that supplementation of aqueous DFM did not significantly improve in vitro fermentation and fibrolytic enzyme activity. In addition, the DFM utilized in this study did not show consistent results by having various effects on ruminal fermentation under different feeding regimens.

Effects of Some Physico-Chemical Conditions of Sioil on Growth and Ionic Balance of the Tobacco Plant (Nicotiana Tabacum L.) I. Effect of Acidity(pH), Moisture(pF) and Anions (Cl-, SO4-) in Soil on Grwth and Ionic Balance of Tobacco (토양(土壤)의 몇가지 이화학적조건(理化學的條件)이 연초(煙草)의 생육(生育) 및 이온평형(平衡)에 미치는 영향(影響) I. 토양(土壤)의 pH, pF와 음(陰)이온(Cl-, SO4-)이 연초(煙草)의 생육(生育) 및 이온평형(平衡)에 미치는 영향(影響))

  • Kim, Jai-Jong;Cho, Seong-Jin
    • Korean Journal of Soil Science and Fertilizer
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    • v.14 no.3
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    • pp.117-129
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    • 1981
  • An experiment with the tobacco plant was conducted in the pots. A sandy humic soil was used with 2 levels of pH, 3.5 and 5.8 with 2 kinds of anions, Cl as $NH_4Cl$ and $SO_4$ as $(NH_4)_2SO_4$, and with 4 levels of pF, 1.5, 2.0, 2.5, and 3.5. The pH-treatment created different N-forms; $NH_4$ at low pH(3.5) and $NO_3$ at high pH (5.8). The results are summarized as follows: 1. At low pH (3.5) with high concentration of $NH_4$ given as $NH_4Cl$, the high content of $NH_4$ and Cl in tobacco resulted in plants suffering from $NH_4$ and Cl toxicity as well as Mn toxicity. As a result of these toxicity, an extremly abnormal growth of tobacco was clearly appeared. In the tobacco grown at low pH with $NH_4$ given as $(NH_4)_2SO_4$, a large amount of the $NH_4$ uptake developed Mg and Ca deficiencies. $NH_4-N$, which had been applied to the soil of high pH (5.8), was almost completely transformed into $NO_3-N$ by nitrification and, on this low acidic soil, the plants were all healthy regardless of Cl or $SO_4$ added together with $NH_4-N$. However, dry matter production was higher and maturity faster when $SO_4$ was used as anion than when Cl was used. 2. High moisture content in soil, to some extent, is necessary for a good development and growth of the tobacco plant. Phosphate uptake seemed to be limited at higher moisture stress. The dry matter yield of tops and roots of tobacco were in the order of pF 1.8 > 2.1 > 2.6 > 3.6, respectively. 3. Data of chemical analysis and dry matter yields of tops and roots showed that the tobacco plant followed the normal (C-A) concept. In the normal growth of plants, the carboxylate content of tops was quite comparable to the estimated (C-A) values. If $NH_4$ content of plants remains in quite high quantities, it must be analysed and taken into consideration for the (C-A) calculation. Al is not transported toward tops in toxic amounts due to its high immobility, it mostly stay in or on the roots, probably due to precipitation as a aolt. When Al is present in high quantities, it has to be considered into the (C-A) calculation.

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A Study on the Changes in Gwi-po from Tang to Jin Dynasty in China - Focusing on the connection type of Jwau-dae(左右隊) - (중국 당대~금대 목조 건축의 귀포 변천에 관한 연구 - 좌우대의 결구 유형을 중심으로 -)

  • Lee, Byung-Chun;Lee, Ho-Yeol
    • Korean Journal of Heritage: History & Science
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    • v.48 no.3
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    • pp.96-119
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    • 2015
  • This research has studied the changes of Gwi-po(轉角包) by taking the cases of China's medieval wooden buildings as objects. The purpose of the study is to examine the time-periodic transition process of Gwi-po through the cases of 71 wooden buildings which were built from Tang(唐) dynasty(AD 618~690 & 705~907) until Jin(金) dynasty(AD 1115~1234) and also designated as 'Major Historical and Cultural Sites Protected at the National Level'. This research has taken note of various frame types of Jwau-dae(左右隊), which are architectural components of Gwi-po, to study the changes and development process of Gwi-po. The results are as follows. An important factor in the transformations of Gwi-po format is the changes in perception of the craftsmen about Jwau-dae, who took charge in the building process. In the early periods, the principles of Yidou sanshen dougong(一斗三升) in constructing ancons of Gwi-po had been well-maintained, while there appeared many different types of Gwi-po in later periods, due to the usage of Jwau-dae and $Shu{\check{a}}$ $t{\acute{o}}u$(?頭) in each Chulmok of Gwi-po. Transitional types of Gwi-po, which were evolved from the earlier ones, are divided into 3 categories by different forms of Jwau-dae, placed on odd number stages. The first one is 'none-$f{\bar{a}}ng$ $t{\acute{o}}u$(無枋頭) type' of Song(AD 960~1127, 1127~1279) and Liao dynasty(AD 907~1125) buildings, which doesn't have $f{\bar{a}}ng$ $t{\acute{o}}u$(枋頭)s, for the reason that Jwau-dae(左右隊) is in direct contact with Gwihan-dae(耳限大). The second one is '$Shu{\check{a}}$ $t{\acute{o}}u$ $f{\bar{a}}ng$ $t{\acute{o}}u$(?頭枋頭) type' of Song(AD 960~1127, 1127~1279) and Jin dynasty(AD 1115~1234), that has $f{\bar{a}}ng$ $t{\acute{o}}u$(枋頭)s of Jwau-dae(左右隊) identical to $Shu{\check{a}}$ $t{\acute{o}}u$(?頭) in form. The last one is '$Xi{\check{a}}o$ $g{\check{o}}ng$ $t{\acute{o}}u$(小?頭) type' of Jin(AD 1115~1234) and Yuan dynasty(AD 1271~1368), which has $f{\bar{a}}ng$ $t{\acute{o}}u$(枋頭)s of Jwau-dae identical to $Xi{\check{a}}o$ $g{\check{o}}ng$ $t{\acute{o}}u$(小?頭) in form. The earlier forms of Gwi-po, which appeared between Tang dynasty(AD 618~690 & 705~907) and Five Dynasties periods(907~960) went through transitional forms of 'non-$f{\bar{a}}ng$ $t{\acute{o}}u$(無枋頭) type', '$Shu{\check{a}}$ $t{\acute{o}}u$ $f{\bar{a}}ng$ $t{\acute{o}}u$(?頭枋頭) type' and '$Xi{\check{a}}o$ $g{\check{o}}ng$ $t{\acute{o}}u$(小?頭) type' and finally had its form settled between Yuan(元, AD 1271~1368) and Ming(明. AD 1368~1644) dynasty periods. In Liao(遼) dynasty period(AD 907~1125), as the buildings got bigger and the tendency of longer eave-exposure was implemented, there grew a certain need to structurally reinforce Gwi-po, on which load of the whole roof is concentrated. Especially, the transition from Tōuxīn $z{\grave{a}}o$(偸心造) style to Jì xīn $z{\grave{a}}o$(計心造) style in this period had a great influence on standardization of Gwi-po, along with None-${\acute{A}}ng$(無仰) style. Furthermore, Wing-type Gong(翼型?), which developed in Liao dynasty(AD 907~1125), is also thought to have had a great influence on the transition from Tōuxīn $z{\grave{a}}o$(偸心造) style to Jì xīn $z{\grave{a}}o$(計心造) style by changing the forms of Gongs(?), such as Gwi-po. However, unlike None-${\acute{A}}ng$(無仰) style, there occurred a gradual change from '$Shu{\check{a}}$ $t{\acute{o}}u$ $f{\bar{a}}ng$ $t{\acute{o}}u$(?頭枋頭) type' to '$Xi{\check{a}}o$ $g{\check{o}}ng$ $t{\acute{o}}u$(小?頭) type' of Gwi-po in $Xi{\grave{a}}$ ${\acute{a}}ng$ style.