• Title/Summary/Keyword: numerical studies

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5 Cases of Patients with Multiple Fractures of Ribs after a Traffic Accident who Improved with the Combination of Korean Medical Admission Treatment: Case Series (교통 사고로 발생한 다발 늑골 골절 환자의 한방복합입원치료로 호전된 증례 보고 5례)

  • Lee, Ji-won;Roh, Ji-ae;Choi, Gyu-cheol;Kim, Dong-jin;Hong, Jeong-su;Kim, Gook-beom;Kim, Hyo-jun;Kim, Sun-a;Kim, Hye-gyeong;Jeong, Wu-jin
    • The Journal of Internal Korean Medicine
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    • v.40 no.3
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    • pp.506-516
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    • 2019
  • Objectives: This study aimed to report five patients who had multiple rib fractures after a traffic accident who improved with the combination of Korean medical admission treatment. Methods: We collected the data of traffic accident patients with multiple rib fractures who were admitted to the Daejeon Jaseng Hospital of Korean Medicine from April 2018 to May 2018 to receive the combinational Korean medical treatment. We observed these cases of patients treated by Acupuncture, Pharmacopuncture, Herbal medicine, Oriental physical therapy, Chuna treatment. We measured the validity of the treatment with a numerical rating scale (NRS) and the European Quality of Life-5 Dimension (EQ5D) at admission, at two weeks, and at the discharge date of hospitalization. Results: At the end of the treatment, all patients showed a decrease in NRS scores and in increase in EQ5D. The median NRS score was 6 (5-7) at the date of admission and 4 (2-7) at two weeks and then decreased to 3 (2-6). The median EQ5D score was 0.513 (0.350-0.752) at the date of admission and 0.692 (0.418-0.913) at two weeks, and then increased to 0.783 (0.671-0.913). Conclusions: After the combination of Korean medicine admission treatment, five patients with multiple rib fractures after a traffic accident showed that the treatments were effective. However, the number of subjects was insufficient and individual efficacy was not measured in this study. Therefore, further studies are needed on this topic.

Numerical Study on the Characteristics of Fluid Flow and Pressure Fluctuation around Human Knuckle in Hydrogymnastics (수중 운동 시 손관절 부위의 유동 및 압력변동 특성에 대한 해석적 연구)

  • Choi, Ji-Hyun;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.390-395
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    • 2019
  • Hydrogymnastics so that sufficient exercise effect can be obtained using the resistance of water has a positive effect on patients who have to receive arthritis or rehabilitation treatment. However, the studies on the effect are insufficient, and the main cause of their effects has not been unclear yet. In this study, in order to identify the main cause of the effects of Hydrogymnastics, conducted Unsteady fluid flow simulation under the same conditions as the actual environment. The analysis model based on real hands, and the pressure fluctuation applied to the knuckle was analyzed by the computational fluid method. During the underwater movement of the hands, Various sizes of vortices were generated between fingers due to skin surface velocity and flow resistance. Pressure of about -500 Pa to +500 Pa is applied by the vortex flow. Also It was confirmed that the positive pressure and the negative pressure were continuously repeated up to maximum + 2000 Pa at the minimum of -2000 Pa at the portion where the direction was changed. Pressure fluctuations with a frequency of 20 Hz to 70 Hz were added continuously for each knuckle. These continuous pressure fluctuations provide a direct massage effect on the knuckles, an It is judged that the blood circulation at the relevant part is positively affected.

A Case Report on a Phantom Limb Pain Patient after Below Knee Amputation using Korean Medicine Treatment (하지 절단 환자의 환상통에 대한 한방 치험1례)

  • Seo, Hung-bum;Bae, Go-eun;Choi, Jin-yong;Seo, Hee-jeong;Shim, So-hyun;Han, Chang-woo;Kim, So-yeon;Choi, Jun-yong;Park, Seong-ha;Yun, Young-ju;Hong, Jin-woo;Kwon, Jung-nam;Lee, In
    • The Journal of Internal Korean Medicine
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    • v.39 no.6
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    • pp.1306-1312
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    • 2018
  • Objectives: This study presented the case of a 49-year-old Korean female with phantom limb pain after below right knee amputation and aimed to assess the effectiveness of Korean medicine treatment. Methods: The patient was treated with scalp acupuncture, electroacupuncture and herbal medicine. We executed a numerical rating scale (NRS), conducted a global assessment (G/A), administrated a Short-Form McGill Pain Questionnaire 2 (SF-MPQ-2) and measured total daily sleep time to evaluate symptom improvement. Results: The patient's G/A scores decreased from 10 to 2 and SF-MPQ-2 points decreased from 20 to 6 after treatment. The total daily sleep time did not changed due to anxiety. Conclusions: This study suggests that Korean medicine treatment could be effective in treating phantom limb pain after amputation. Further studies are needed.

A Study on the Effect of Artificial Cutting Slot on the Fragmentation and Vibration Propagation in the Full-scaled Concrete Block Blasting (콘크리트 블록 발파 실험을 통한 인공 슬롯 자유면이 진동전파 및 파쇄효과에 미치는 영향에 관한 연구)

  • Oh, Se-Wook;Min, Gyeong-Jo;Park, Se-Woong;Park, Hoon;Noh, You-Song;Suk, Chul-Gi;Cho, Sang-Ho
    • Tunnel and Underground Space
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    • v.28 no.6
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    • pp.692-705
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    • 2018
  • Ground vibration is one of the remarkable issues in tunnel blasting. In recent studies, to improve the fragmentation with reduction of ground vibration in tunnel blasting, a vibration-controlled blasting method with artificial cutting slot near the center-cut holes has been suggested. This study examines the effect of the different arrangement of artificial cut-slot on the vibration reduction and fragmentation by performing the full-scaled concrete block blast experiments and the numerical simulations with 3D-DFPA. The results show that the existence of artificial slot contributes to the improvement of vibration reduction, blast fragmentation and the efficiency of the cutting slot blast. It can be explained that the artificial slot play a free surface role and should decrease the burden between the cut holes. Crater volumes of the blasted concrete blocks were measured by 3-dimensional digital image analysis and compared with the ideal standard crater volume which can be calculated by theoretical standard blast design method. As a result, the ratio of burden and hole diameter which should achieve the standard crater in the cut-hole blasting were suggested.

Probabilistic Fatigue Life Evaluation of Steel Railway Bridges according to Live-Dead Loads Ratio (강철도교의 활하중-사하중 비에 따른 확률기반 피로수명 평가)

  • Lee, Sangmok;Lee, Young-Joo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.1
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    • pp.339-346
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    • 2019
  • Various studies have been conducted to evaluate the probabilistic fatigue life of steel railway bridges, but many of them are based on a relatively simple model of crack propagation. The model assumes zero minimum stress and constant loading amplitude, which is not appropriate for the fatigue life evaluation of railway bridges. Thus, this study proposes a new probabilistic method employing an advanced crack propagation model that considers the live-dead load ratio for the fatigue life evaluation of steel railway bridges. In addition, by using the rainflow cycle counting algorithm, it can handle variable-amplitude loading, which is the most common loading pattern for railway bridges. To demonstrate the proposed method, it was applied to a numerical example of a steel railway bridge, and the fatigue lives of the major components and structural system were estimated. Furthermore, the effects of various ratios of live-dead loads on bridge fatigue life were examined through a parametric study. As a result, with the increasing live-dead stress ratio from 0 to 5/6, the fatigue lives can be reduced by approximately 30 years at both the component and system levels.

DEM-based numerical study on discharge behavior of EPB-TBM screw conveyor for rock (EPB-TBM 암반굴착시 스크류컨베이어의 배토 거동에 대한 DEM 기반 수치해석적 연구)

  • Lee, Gi-Jun;Kwon, Tae-Hyuk;Kim, Huntae
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.1
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    • pp.127-136
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    • 2019
  • Tunnel construction by TBMs should be supported by the performance of a screw conveyor in order to obtain the optimum penetration rate, so studies related to the screw conveyor performance have been being conducted. Compared to the study on the performance of the screw conveyor for the soil, however, the research on the performance of the screw conveyor for the rock is insufficient. Considering the domestic tunnel sites with more rock layers than soil layers, simulation of discharge of 6 types of rock chips by the screw conveyor was conducted using DEM. Regardless of the shape and volume of the rock chips, the discharge rates of the rock chips by the parallel placed screw conveyor at a speed of 10 RPM in the same rock mass were about 20% (standard deviation: 1.3%) of the maximum volume of discharge rate by the screw conveyor. It is expected that this study can be used as a reference material for screw conveyor design and operation in TBM excavations in rock masses.

Hysteretic characteristics of steel plate shear walls: Effects of openings

  • Ali, Mustafa M.;Osman, S.A.;Yatim, M.Y.M.;A.W., Al Zand
    • Structural Engineering and Mechanics
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    • v.76 no.6
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    • pp.687-708
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    • 2020
  • Openings in steel plate shear walls (SPSWs) are usually used for decorative designs, crossing locations of multiple utilities and/or structural objectives. However, earlier studies showed that generating an opening in an SPSW has a negative effect on the cyclic performance of the SPSW. Therefore, this study proposes tripling or doubling the steel-sheet-plate (SSP) layer and stiffening the opening of the SPSW to provide a solution to undesirable opening effects, improve the SPSW performance and provide the infill option of potential strengthening measures after the construction stage. The study aims to investigate the impact of SSP doubling with a stiffened opening on the cyclic behaviour, expand the essential data required by structural designers and quantify the SPSW performance factors. Validated numerical models were adopted to identify the influence of the chosen parameters on the cyclic capacity, energy dissipation, ductility, seismic performance factors (SPF) and stiffness of the suggested method. A finite Element (FE) analysis was performed via Abaqus/CAE software on half-scale single-story models of SPSWs exposed to cyclic loading. The key parameters included the number of SSP layers, the opening size ratios corresponding to the net width of the SSP, and the opening shape. The findings showed that the proposed assembly method found a negligible influence in the shear capacity with opening sizes of 10, 15, 20%. However, a deterioration in the wall strength was observed for openings with sizes of 25% and 30%. The circular opening is preferable compared with the square opening. Moreover, for all the models, the average value of the obtained ductility did not show substantial changes and the ultimate shear resistance was achieved after reaching a drift ratio of 4.36%. Additionally, the equivalent sectional area of the SSP in the twin and triple configuration of the SPSWs demonstrated approximately similar results. Compared with the single SSP layer, the proposed configuration of the twin SSP layer with a stiffened opening suggest to more sufficiency create SSP openings in the SPSW compared to that of other configurations. Finally, a tabular SPF quantification is exhibited for SPSWs with openings.

A Study on the Optimal Pre-loading Calculation of Strut of Retaining Wall through Numerical Interpretation (수치해석을 통한 흙막이벽체 버팀보의 최적 선행하중 산정에 관한 연구)

  • Moon, In Jong;Jang, Seung Ju;Lee, Kang Il
    • Journal of the Korean Geosynthetics Society
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    • v.20 no.2
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    • pp.45-56
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    • 2021
  • As the utilization of the underground space is activated, deep excavation of ground has been conducted for the installation of underground structures, the earth retaining wall has widely used to minimize deformation of the excavated ground. In particular, as deep excavation is actively progressing in an urban area where structures are concentrated, methods to minimize the deformation of wall have been devised to prevent damage to the structure adjacent to the wall, and one of these methods is the pre-loading method. This method is a method of suppressing the deformation of wall by actively applying a load on the strut to be installed in wall, and research on this method has been conducted recently. However, although related studies have been actively conducted, the management standard for the pre-loading of bracing has not been clearly presented until now. In addition, since the working force in the strut may increase depending on the depth of excavation or the soil condition of the backfill, the magnitude of the pre-loading that can be applied to the brace may decrease. Nevertheless, the magnitude of the pre-loading (more than 50% of the working load) proposed by the previous research results has been uniformly applied to the strut. In this study, 3D finite element analysis was performed to evaluate the application range of the pre-loading of H-beam strut according to the soil conditions of backfill. As a result of the analysis, it was found that there is a very high possibility that a problem may occur in the stability of the structure of strut due to the earth pressure and the pre-loading when the soil condition is weak and deep excavation proceeds. And it was found that the application range of the pre-loading was 5%~70% of the working load in strut.

Relationship between Stock Market & Housing Market Trends and Liquidity (주식시장과 주택시장의 동향 및 유동성과의 관계)

  • Choi, Jeong-Il
    • Journal of Digital Convergence
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    • v.19 no.6
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    • pp.133-141
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    • 2021
  • Governments of each country are actively implementing fiscal expansion policies to recover the real economy after Corona 19. In Korea, the stock market and housing market are greatly affected as liquidity in the market increases due to the implementation of disaster subsidies and welfare policies. The purpose of this study is to analyze the relationship between stock market and housing market trends and liquidity. Data were collected by the Bank of Korea and Kookmin Bank. The analysis period is from January 2000 to December 2020, and monthly data are used. For empirical analysis, the rate of change from the same month of the previous year was calculated for each variable, and numerical analysis, index analysis, and model analysis were performed. As a result of the analysis, it was found that the stock index showed a positive(+) relationship with the house price, while a negative(-) relationship with M2. Previous studies have suggested that, in general, an increase in liquidity affects the stock market and the housing market, and inflation also rises. In this study, it was found that the stock market and the housing market had an effect on each other. However, it was investigated that liquidity showed an inverse relationship with the stock market and had no relationship with the housing market. Through this, this study estimated that there is a time difference in the relationship between liquidity and the stock market & housing market.

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
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    • v.39 no.2
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    • pp.93-101
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    • 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.