• Title/Summary/Keyword: dense

Search Result 4,031, Processing Time 0.035 seconds

A Study on the Changes in Residential Environments after Residential Environments Improvement Projects (주거환경개선사업이후 주거 환경 변화에 관한 연구 - 대구광역시 주거환경개선사업의 물리적 환경 분석을 중심으로 -)

  • Kim, Young-Hwa;Lee, Sang-Hong
    • Journal of the Architectural Institute of Korea Planning & Design
    • /
    • v.34 no.10
    • /
    • pp.3-12
    • /
    • 2018
  • This research aims at analyzing the changes in residential environment after a residential environment improvement project focusing on the analysis into the physical environment of a residential environment improvement project, and examining in what direction the changes by residents' own efforts occurred after public support, such as infrastructure. The present residence development method has become different from the previous pulling down method and is focused on regeneration. By examining in what direction the target residence is being changed because of the development by residents' own efforts after the government's public investment at this time, this study also aims at investigating the direction to develop a guideline for residential improvement for later improvement of deteriorated residence. As for the contents of the analysis, changes in public support, such as infrastructure, and other areas after the residential environment improvement project were compared and analyzed from the land use, street system, and condition of buildings before the residential environment improvement project through field survey, geographic information system(GIS), registered land and building data and so on. The biggest change since the support from the government was that at the beginning of the project, the application of special provision of building laws and different financial supports led to lots of newly built buildings. Since then, their number has decreased rapidly, and in most cases, there have been some changes in part, such as changes in the use of land or repair of disposal tanks. Most newly built buildings were multi-household houses, and it has caused road capacity and parking lot capacity, etc., to be exceeded, which has worsened the pleasantness of the living environment. In addition, other problems have also appeared, for example, the lack of residence supporting facilities yet with a higher level of residential density. Regarding the changes in the residential environment after the residential environment improvement project, maintenance of houses were conducted in some degree as diverse alleviation policies to improve poor residence, yet the absence of the guideline for the direction of developing the whole district has made the residence environment more dense and deteriorated. To solve these problems, in advance to a residential improvement project, specific management methods based on short-, mid- and long-term plans for the direction of development by residents' own efforts and a sustainable guideline seem to be necessary.

Transient Liquid Phase Sinter Bonding with Tin-Nickel Micro-sized Powders for EV Power Module Applications (주석-니켈 마이크로 분말을 이용한 EV 전력모듈용 천이액상 소결 접합)

  • Yoon, Jeong-Won;Jeong, So-Eun
    • Journal of the Microelectronics and Packaging Society
    • /
    • v.28 no.2
    • /
    • pp.71-79
    • /
    • 2021
  • In this study, we have successfully fabricated the Sn-Ni paste and evaluated the bonding properties for high-temperature endurable EV (Electric Vehicle) power module applications. From evaluating of the micro-structural changes in the TLPS (Transient Liquid Phase Sintering) joints with Sn and Ni contents in the Sn-Ni pastes, a lack of Ni powders and Ni particle agglomerations by Ni surplus were observed in the Sn-20Ni and Sn-50Ni joints (in wt.%), respectively. In contrast, relatively dense microstructures are observed in the Sn-30Ni and Sn-40Ni TLPS joints. From differential scanning calorimetry (DSC) thermal analysis results of the fabricated Sn-Ni paste and TLPS bonded joints, we confirmed that the complete reactions of Sn with Ni to form Ni-Sn intermetallic compounds (IMCs) at bonding temperatures occurred, and there is no remaining Sn in the joints after TLPS bonding. In addition, the interfacial reactions and IMC phase changes of the Sn-30Ni joints under various bonding temperatures were reported, and their mechanical shear strength were investigated. The TLPS bonded joints were mainly composed of residual Ni particles and Ni3Sn4 intermetallic phase. The average shear strength tended to increase with increasing bonding temperature. Our results indicated a high shear strength value of approximately 30 MPa at a bonding temperature of 270 ℃ and a bonding time of 30 min.

Study on the Rational Construction Method Using Analysis of the Case Study of PHC Pile Foundation in Song-Do Area (송도지역 내 PHC 말뚝기초 적용사례분석을 통한 적정 시공방법 연구)

  • Lee, Byengho;Lee, Jonghwi;Chun, Byungsik
    • Journal of the Korean GEO-environmental Society
    • /
    • v.12 no.3
    • /
    • pp.55-61
    • /
    • 2011
  • Song-Do international city is the area developed in large-scale land reclamation. Song-Do area consists of reclamation layer, sedimentary layer(loose silt, soft clay and sand alternating) and residual layer from the ground surface. Therefore, using pile foundation is inevitable to build structures safely. In this area, driven PHC piles have been generally constructed in terms of environmental and economic conditions. As a result of analyzing 4 sites in Song-Do district 5 and 7 recently, the method of driving pile has many problems because of existence of rigid soil in sedimentary layer and installation of more than 30m piles. In this case, when installing piles by drive after pre-boring up to appropriate depth, the results of constructability analysis were very good. And in the economic efficiency, although 4% of construction cost rose, it was a very slight increase in comparison with improvement of workability. In the case of the stability, more than 70% compared to the allowable stress of piles was satisfied through the load test. As a result, when PHC piles is installed in Song-Do district, the proper construction method is that piles are located at bearing layer after boring rigid sand layer.

Effect of high amylose corn starch/dextrin on quality of non-fried instant noodles (고아밀로스 옥수수전분/덱스트린의 첨가가 건면의 품질에 미치는 영향)

  • You, Jae Geun;Lee, Ju Hun;Park, Eun Young
    • Korean Journal of Food Science and Technology
    • /
    • v.52 no.6
    • /
    • pp.655-660
    • /
    • 2020
  • High amylose corn starch and dextrin (acid-treated at 30, 40 and 50℃ denominated as Dextrin30, Dextrin40 and Dextrin50) were added to non-fried instant noodles. X-ray diffraction pattern, water absorption, cooking loss, microstructure, and textural properties of non-fried instant noodles were investigated. The addition of high amylose corn starch/dextrin induced a slight peak intensity at 20o in the X-ray pattern indicating the insignificant formation of amylose-lipid complex. Non-fried instant noodles including high amylose corn starch/dextrin showed lower water absorption than the control. Dense microstructure in transverse section of noodles was observed in non-fried instant noodles including high amylose corn starch/dextrin except Dextrin50. Also, the addition of high amylose corn starch/dextrin induced low tensile strength, high firmness, and high stickiness. However, non-fried instant noodles containing Dextrin50 showed a loose microstructure and high cooking loss (3.98%), which might be associated with the textural properties such as the lowest tensile strength (0.17 N), lowest increase in firmness (46.77 N) and highest stickiness (18.43 N).

Determinants of Attitude toward the Electronic Wristband System to Tackle the Spread of COVID-19 -Focused on the Interaction between Class and Age- (코로나19 자가격리 안심밴드에 대한 태도 결정 요인 -계층과 연령의 상호작용을 중심으로-)

  • Lee, Jae-Wan
    • The Journal of the Korea Contents Association
    • /
    • v.21 no.6
    • /
    • pp.285-294
    • /
    • 2021
  • This study analyzes the factors that determine the attitude toward the electronic wristband(smartband) to check the position of self-quarantine subjects due to COVID-19. Furthermore, I analyze the interaction of class and age among the factors that determine attitudes toward the electronic wristband. In this study, the attitude toward self-quarantine electronic wristband is analyzed as a binary logit model, focusing on class and age. As a result of the analysis, the middle class significantly agreed with the self-quarantine electronic wristband compared to the lower class, and the older the person, the more in favor. On the other hand, the interaction between the class and the age shows that the age weakens the positive effect on the attitude of the self-quarantine electronic wristband in the middle and upper middle classes. The implication of this study is that it is necessary to push for mandatory electronic wristband in areas with high proportion of high-aged people with positive attitude toward self-quarantine electronic wristband and in the same age group, the approval rate is low, so it is necessary to promote mandatory electronic wristband in areas where the vulnerable class is dense.

A Study on the Application of a Drone-Based 3D Model for Wind Environment Prediction

  • Jang, Yeong Jae;Jo, Hyeon Jeong;Oh, Jae Hong;Lee, Chang No
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
    • /
    • v.39 no.2
    • /
    • pp.93-101
    • /
    • 2021
  • Recently, with the urban redevelopment and the spread of the planned cities, there is increasing interest in the wind environment, which is related not only to design of buildings and landscaping but also to the comfortability of pedestrians. Numerical analysis for wind environment prediction is underway in many fields, such as dense areas of high-rise building or composition of the apartment complexes, a precisive 3D building model is essentially required in this process. Many studies conducted for wind environment analysis have typically used the method of creating a 3D model by utilizing the building layer included in the GIS (Geographic Information System) data. These data can easily and quickly observe the flow of atmosphere in a wide urban environment, but cannot be suitable for observing precisive flow of atmosphere, and in particular, the effect of a complicated structure of a single building on the flow of atmosphere cannot be calculated. Recently, drone photogrammetry has shown the advantage of being able to automatically perform building modeling based on a large number of images. In this study, we applied photogrammetry technology using a drone to evaluate the flow of atmosphere around two buildings located close to each other. Two 3D models were made into an automatic modeling technique and manual modeling technique. Auto-modeling technique is using an automatically generates a point cloud through photogrammetry and generating models through interpolation, and manual-modeling technique is a manually operated technique that individually generates 3D models based on point clouds. And then the flow of atmosphere for the two models was compared and analyzed. As a result, the wind environment of the two models showed a clear difference, and the model created by auto-modeling showed faster flow of atmosphere than the model created by manual modeling. Also in the case of the 3D mesh generated by auto-modeling showed the limitation of not proceeding an accurate analysis because the precise 3D shape was not reproduced in the closed area such as the porch of the building or the bridge between buildings.

Estimation of soil moisture based on Sentinel-1 SAR data: Assessment of soil moisture estimation in different vegetation condition (Sentinel-1 SAR 토양수분 산정 연구: 식생에 따른 토양수분 모의평가)

  • Cho, Seongkeun;Jeong, Jaehwan;Lee, Seulchan;Choi, Minha
    • Journal of Korea Water Resources Association
    • /
    • v.54 no.2
    • /
    • pp.81-91
    • /
    • 2021
  • Synthetic Apreture Radar (SAR) is attracting attentions with its possibility of producing high resolution data that can be used for soil moisture estimation. High resolution soil moisture data enables more specific observation of soil moisture than existing soil moisture products from other satellites. It can also be used for studies of wildfire, landslide, and flood. The SAR based soil moisture estimation should be conducted considering vegetation, which affects backscattering signals from the SAR sensor. In this study, a SAR based soil moisture estimation at regions covered with various vegetation types on the middle area of Korea (Cropland, Grassland, Forest) is conducted. The representative backscattering model, Water Cloud Model (WCM) is used for soil moisture estimation over vegetated areas. Radar Vegetation Index (RVI) and in-situ soil moisture data are used as input factors for the model. Total 6 study areas are selected for 3 vegetation types according to land cover classification with 2 sites per each vegetation type. Soil moisture evaluation result shows that the accuracy of each site stands out in the order of grassland, forest, and cropland. Forested area shows correlation coefficient value higher than 0.5 even with the most dense vegetation, while cropland shows correlation coefficient value lower than 0.3. The proper vegetation and soil moisture conditions for SAR based soil moisture estimation are suggested through the results of the study. Future study, which utilizes additional ancillary vegetation data (vegetation height, vegetation type) is thought to be necessary.

The Analysis of fragmentation on the Jirisan National Park for the Improvement of Asiatic Black Bear's habitat environment (반달가슴곰 서식환경 개선을 위한 지리산 국립공원 파편화 분석)

  • Bae, Je-Sun;Oh, Choong-Hyeon
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.24 no.1
    • /
    • pp.1-14
    • /
    • 2021
  • The Ministry of Environment of Korea has been releasing Asiatic black bears since 2004 at Jirisan National Park. It exceeded the target number of Asiatic black bears in 2018. As of July 2020, in addition to 67 traceable bears, many Asiatic black bears are dispersed outside Jirisan National Park. Jirisan National Park is a very dense place with more than 3 million visitors every year. In this study, the roads and trails through Jirisan National Park were considered to be the main dispersion factors of Asiatic black bears, and the fragmentation analysis was conducted. As of July 2017, the length of roads and trails in Jirisan National Park was 363.4km. Based on this, Jirisan National Park was fragmented into 163 patches. There is only one place that maintains a single area of more than 50㎢ that is suitable for large mammals to inhabit, and 141 places are less than 5㎢. There are 6 patches of 24 to 200㎢ area suitable for living of large mammals including Asiatic black bears, in Jirisan National Park. Compared to the announcement made by the Korea National Park Service in 2014, activities of Asiatic black bears were rare in areas below 5㎢ area and the frequency of activities was high in more than 20㎢ area. This shows that human activities in protected areas such as national parks can directly affect the activities of wild animals, including Asiatic black bears. Therefore, efforts should be made to improve the habitat of Asiatic black bears by reducing the pressure of visiting for Jirisan National Park. In addition, as a result of analyzing the fragmentation of the park's natural conservation zone 107.7km, 45% of the trail of Jirisan National Park, was opened, which is more fragmentation than other use zones. The park nature conservation zone accounts for about 32% of the total area of Jirisan National Park, but the average patch area is only 2.93㎢ and seven large shelters are located. Therefore the Asiatic black bears are negatively affected. This is the result of inconsistent national park use zone setting and actual park management. In overseas countries, research is active on the negative effects of human activity on ecosystems in protected areas. However, there is a lack of research of that in Korea. Thus, that research is required for protection area management in the future.

Analysis of Effect on Camera Distortion for Measuring Velocity Using Surface Image Velocimeter (표면영상유속측정법을 이용한 유속 측정 시 카메라 왜곡 영향 분석)

  • Lee, Jun Hyeong;Yoon, Byung Man;Kim, Seo Jun
    • Ecology and Resilient Infrastructure
    • /
    • v.8 no.1
    • /
    • pp.1-8
    • /
    • 2021
  • A surface image velocimeter (SIV) measures the velocity of a particle group by calculating the intensity distribution of the particle group in two consecutive images of the water surface using a cross-correlation method. Therefore, to increase the accuracy of the flow velocity calculated by a SIV, it is important to accurately calculate the displacement of the particle group in the images. In other words, the change in the physical distance of the particle group in the two images to be analyzed must be accurately calculated. In the image of an actual river taken using a camera, camera lens distortion inevitably occurs, which affects the displacement calculation in the image. In this study, we analyzed the effect of camera lens distortion on the displacement calculation using a dense and uniformly spaced grid board. The results showed that the camera lens distortion gradually increased in the radial direction from the center of the image. The displacement calculation error reached 8.10% at the outer edge of the image and was within 5% at the center of the image. In the future, camera lens distortion correction can be applied to improve the accuracy of river surface flow rate measurements.

Comparison of Blood Gas, Biochemical Factors, and Hormone Concentrations, and Muscle Stress Response Factors of Chickens in General Farms and Animal Welfare Farms (일반농장과 동물복지농장 닭의 혈액 내 gas, 생화학인자, 호르몬 농도 및 근육 내 스트레스 반응인자 비교)

  • Kim, Hee-Eun;Park, Jin-Ryong;Lee, Jeong-Eun;Kang, Da-Rae;Jang, Ae-Ra;Choe, Ho-Sung;Shim, Kwan-Seob
    • Korean Journal of Organic Agriculture
    • /
    • v.29 no.3
    • /
    • pp.415-427
    • /
    • 2021
  • It is generally recognized that high stocking density can increase the risk of immune dysfunction and reduction in productivity cause of elevated stress in broiler farm. The domestic livestock industry is implementing a certification system for animal welfare and livestock farms to reduce the problem of dense breeding. This study compared broiler from the general farm and animal welfare farm to confirm the effectiveness of animal welfare farms against stress. Gas concentrations in a farm of general and animal welfare farms were analyzed, blood (n=10) of the 28-day-old broiler was collected, the partial pressure of the gas in the blood was analyzed using whole blood, and biochemical factors and hormones were analyzed using the serum. Glycogen and L-lactate are analyzed using ELISA kit on finely pulverized muscles (n=10). CO2 and NH3 levels in the farm were significantly higher in general farm. Partial carbon dioxide tension (PCO2) in blood was significantly higher and partial oxygen tension (PO2) was significantly lower in the general farm. Creatinine (CREA), glucose (GLU), aspartateaminotransferase (AST), and creatinekinase (CK) in the blood were significantly higher in the general farm, and total protein (TP) and globulin (GLOB) were significantly higher in animal welfare farm. Blood corticosterone and norepinephrine were significantly higher in general farm and epinephrine was significantly higher in animal welfare farm. These results imply that animal welfare farm provides a stress-reduced breeding environment.