• 제목/요약/키워드: Force measurement

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An Analysis of The Effect of a Port on The Living Conditions of Its Neighborhood Area (항만이 인근지역 생활여건에 미친 영향 분석)

  • Kim, Chang Soo
    • Journal of Korea Port Economic Association
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    • v.37 no.4
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    • pp.71-87
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    • 2021
  • This study aims to reveal how a port affects the living conditions of its neighborhood area with a case study of Pusan New Port and to suggest several implications to port policy. PLS-SEM reflective measurement model satisfies the criteria on reliability and validity, and also structural model meets the criteria in terms of R2, path coefficients' significance and predictive relevance(Q2). The results of PLS-SEM support the hypotheses of this study: The expansion of Pusan New Port contributes to the improvement of living conditions of Gangseo-gu(nearby area) through its significant and sequential effects on the employment and population increase of Gangseo-gu. The originality of this study can be found in enunciating that a port plays a role as a driving force of the betterment of living conditions of its nearby Gu-level area. In terms of policy, central and local governments and port related companies should cooperate with each other to reinforce the acceptability of port policy through the improvement of the living conditions of port neighborhood area. To evaluate comprehensively the influence of a port on its neighborhood area, a further study needs to identify how a port affects the quality of life of the area or what kinds of socio-economic effects a port has on the area.

Analysis of Tree Roughness Evaluation Methods Considering Depth-Dependent Roughness Coefficient Variation (수심별 조도계수 변화를 고려한 수목 조도공식 특성 분석)

  • Du Han Lee;Dong Sop Rhee
    • Ecology and Resilient Infrastructure
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    • v.10 no.3
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    • pp.51-63
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    • 2023
  • Riverine tree management is crucial in realizing a balance between flood control and ecological preservation, which requires an accurate assessment of the impact of trees on river water elevations. In this study, eight different formulas for evaluating vegetation roughness considering the drag force acting on trees, were reviewed, and the characteristics and applicability of these methods were evaluated from a practical engineering perspective. The study compared the characteristics of vegetation roughness measurement methods for calculated roughness coefficients at different water depths and analyzed factors such as effects of tree canopy width, tree density and diameter, and tree stiffness coefficient, and water level estimation results. A comparison of roughness coefficients at the same water depths revealed that the Kouwen and Fathi-Moghadam formulas and the Fischenich formula yield excessive drag coefficients compared to other formulas. Factors such as channel geometry, tree diameter, and tree density showed varying trends depending on the formula but did not exhibit excessive outliers. Formulas considering the tree stiffness coefficient, such as the Freeman et al.'s formula and the Whittaker et al.'s formula, showed significant variations in drag coefficients depending on the stiffness coefficient. When applied to small- and medium-sized virtual rivers in South Korea using the drag coefficient results from the eight formulas, the results indicated a maximum increase in water level of approximately 0.2 to 0.4 meters. Based on this review, it was concluded that the Baptist et al., Huthoff et al., Cheng, Luhar, and Nepf's formulas, which exhibit similar characteristics and low input data uncertainties, are suitable for practical engineering applications.

Development of Steel Composite Cable Stayed Bridge Weigh-in-Motion System using Artificial Neural Network (인공신경망을 이용한 강합성 사장교 차량하중분석시스템 개발)

  • Park, Min-Seok;Jo, Byung-Wan;Lee, Jungwhee;Kim, Sungkon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.6A
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    • pp.799-808
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    • 2008
  • The analysis of vehicular loads reflecting the domestic traffic circumstances is necessary for the development of adequate design live load models in the analysis and design of cable-supported bridges or the development of fatigue load models to predict the remaining lifespan of the bridges. This study intends to develop an ANN(artificial neural network)-based Bridge WIM system and Influence line-based Bridge WIM system for obtaining information concerning the loads conditions of vehicles crossing bridge structures by exploiting the signals measured by strain gauges installed at the bottom surface of the bridge superstructure. This study relies on experimental data corresponding to the travelling of hundreds of random vehicles rather than on theoretical data generated through numerical simulations to secure data sets for the training and test of the ANN. In addition, data acquired from 3 types of vehicles weighed statically at measurement station and then crossing the bridge repeatedly are also exploited to examine the accuracy of the trained ANN. The results obtained through the proposed ANN-based analysis method, the influence line analysis method considering the local behavior of the bridge are compared for an example cable-stayed bridge. In view of the results related to the cable-stayed bridge, the cross beam ANN analysis method appears to provide more remarkable load analysis results than the cross beam influence line method.

Optimization of Sensor Location for Real-Time Damage assessment of Cable in the cable-Stayed Bridge (사장교 케이블의 실시간 손상평가를 위한 센서 배치의 최적화)

  • Geon-Hyeok Bang;Gwang-Hee Heo;Jae-Hoon Lee;Yu-Jae Lee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.6
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    • pp.172-181
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    • 2023
  • In this study, real-time damage evaluation of cable-stayed bridges was conducted for cable damage. ICP type acceleration sensors were used for real-time damage assessment of cable-stayed bridges, and Kinetic Energy Optimization Techniques (KEOT) were used to select the optimal conditions for the location and quantity of the sensors. When a structure vibrates by an external force, KEOT measures the value of the maximum deformation energy to determine the optimal measurement position and the quantity of sensors. The damage conditions in this study were limited to cable breakage, and cable damage was caused by dividing the cable-stayed bridge into four sections. Through FE structural analysis, a virtual model similar to the actual model was created in the real-time damage evaluation method of cable. After applying random oscillation waves to the generated virtual model and model structure, cable damage to the model structure was caused. The two data were compared by defining the response output from the virtual model as a corruption-free response and the response measured from the real model as a corruption-free data. The degree of damage was evaluated by applying the data of the damaged cable-stayed bridge to the Improved Mahalanobis Distance (IMD) theory from the data of the intact cable-stayed bridge. As a result of evaluating damage with IMD theory, it was identified as a useful damage evaluation technology that can properly find damage by section in real time and apply it to real-time monitoring.

Development Direction of Maritime Manned-Unmanned Systems through Measurement of Combat Effectiveness against Major Threats on Sea Lines of Communication (해상교통로 상 주요 위협별 전투 효과 측정을 통한 해양 유·무인 복합체계 발전방향)

  • Yong-Hoon Kim;Yonghoon Ha
    • Journal of Industrial Convergence
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    • v.21 no.11
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    • pp.29-41
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    • 2023
  • In this study, assuming that the maritime manned-unmanned systems, which will be used as the main force of the ROK Navy in the future, conducts its sea line of communication(SLOC) protection operations, the combat effectiveness against major threats was measured, and through this, the development direction of the manned-unmanned systems was suggested. Multi-criteria decision-making techniques such as Delphi and AHP were used to measure combat effectiveness, and the AHP survey was conducted on 40 naval officers, including 25 senior officers who are well-understood in the combat effectiveness of the weapons system and MUM-T. As an evaluation index for measuring combat effectiveness, the OODA loop was set as the main attribute, followed by Observe(0.358), Orient(0.315), Act(0.217), and Decide(0.110). The combat effectiveness of each major threat in SLOC, the lowest alternative, was measured to be 1.68 times higher than the response to maritime conflicts in neighboring countries and 3.61 times higher than the response to transnational threats. These results are expected to support rational decision-making in determining the level of technology required for acquisition of marine manned-unmanned systems and establishing operational plans for naval forces.

A Psychological Approach to Mass Culture for Investigation (대중문화의 심리학적 접근과 탐색 )

  • You-Kyung Yoon ;Jee-Young Chae
    • Korean Journal of Culture and Social Issue
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    • v.11 no.3
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    • pp.67-89
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    • 2005
  • This overview study of mass culture is based on an academic point of view and based thereon an investigation of mass culture from a psychological standpoint follows. This study reviewed previous studies of mass culture that have been done so far divided into Producer-oriented, Text Decoding-oriented, and Recipient Theory, according to subjects of the study. The studies were also reviewed from the viewpoints of industry, consumer science, education, and developmental psychology. Further, it was discussed how trends and limitations in research were covered according to each viewpoint on mass culture. Based on the analysis, this study aims to promote overall psychological interest in studies of mass culture; to present the necessity of analysis and measurement of emotional experience on mass culture; to increase the roles of industrial and consumer science approaches in terms of planning and culture; to change the viewpoint of developmental psychology that accepts youth culture positively; and, to present interdisciplinary studies related to mass culture. Mass culture has already penetrated deeply into real life but there are few analyses and interpretations of mass culture in terms of psychology. This study is meaningful from the aspect that discussion of mass culture has been placed in a position that recognizes the entity of and interest in mass culture. Through this study, I hope that the scope of interest in psychology will expand and that approaches to mass culture will become more diversified.

Expert Opinions and Recommendations for the Clinical Use of Quantitative Analysis Software for MRI-Based Brain Volumetry (뇌 자기공명영상 뇌용적 분석 소프트웨어의 임상적 적용에 대한 전문가 의견과 권고안)

  • Ji Young Lee;Ji Eun Park;Mi Sun Chung;Se Won Oh;Won-Jin Moon;Aging and Neurodegeneration Imaging (ANDI) Study Group, Korean Society of Neuroradiology (KSNR)
    • Journal of the Korean Society of Radiology
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    • v.82 no.5
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    • pp.1124-1139
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    • 2021
  • The objective assessment of atrophy and the measurement of brain volume is important in the early diagnosis of dementia and neurodegenerative diseases. Recently, several MR-based volumetry software have been developed. For their clinical application, several issues arise, including the standardization of image acquisition and their validation of software. Additionally, it is important to highlight the diagnostic performance of the volumetry software based on expert opinions. We instituted a task force within the Korean Society of Neuroradiology to develop guidelines for the clinical use of MR-based brain volumetry software. In this review, we introduce the commercially available software and compare their diagnostic performances. We suggest the need for a standard protocol for image acquisition, the validation of the software, and evaluations of the limitations of the software related to clinical practice. We present recommendations for the clinical applications of commercially available software for volumetry based on the expert opinions of the Korean Society of Neuroradiology.

Normative blood pressure references for Korean children and adolescents (한국 소아 청소년 정상 혈압 참고치)

  • Lee, Chong Guk;Moon, Jin Soo;Choi, Joong-Myung;Nam, Chung Mo;Lee, Soon Young;Oh, Kyungwon;Kim, Young Taek
    • Clinical and Experimental Pediatrics
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    • v.51 no.1
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    • pp.33-41
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    • 2008
  • Purpose : It is now understood that blood pressure (BP) measurement in the routine pediatric examination is very important because of the relevance of childhood BP to pediatric health care and the development of adult essential hypertension. There hasn't been a reference table of BP for Korean children and adolescents up to now. This study was to make normative BP references and to provide criteria of hypertension for Korean children and adolescents. Methods : BP measurements were done on 57,433 Koean children and adolescents (male: 29,443, female: 27,990), aged 7 to 20 years, in 2005. Heights and weights were measured simultaneously. Oscillometric devices, Dinamap Procare 200 (GE Inc., Milwaukee, Wi, USA), were used for the measurements. BPs were measured 2 times and mean levels were gathered for the analysis. Outliers of 2,373 subjects with overweight per height, over +3SD, were excluded for the analysis. For the BP centiles adjusted by sex, age and height, fixed modified LMS method which was adopted from the mixed effect model of 2004 Task Force in NHLBI (USA) was used. Results : Normative BP tables for Korean children and adolescents adjusted for height percentiles (5th, 10th, 25th, 50th, 75th, 90th, 95th), gender (male, female) and age(7 to 18 years) were completed. Height centiles of Korean children and adolescents are available from Korean Center for Disease Control and Prevention homepage, http://www.cdc.go.kr/webcdc/. Criteria of hypertension (95th, 99th percentile) and normal range of BP (50th, 90th) adjusted for height percentiles, age and gender were made. Conclusion : This is the first study to make normative BP tables and define hypertension for the Korean children and adolescents. Reliability and accuracy of Dinamap Procare 200 oscillometer for BP measurements remains debatable.

Analysis of Occlusal Contacts Using Add-picture Method (Add-picture 방법을 이용한 교합접촉점 분석)

  • Park, Ko-Woon;Cho, Lee-Ra;Kim, Dae-Gon;Park, Chan-Jin
    • Journal of Dental Rehabilitation and Applied Science
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    • v.29 no.1
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    • pp.45-58
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    • 2013
  • The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.

Meat Quality of Highly Marbled Imported Beef with Reference to Hanwoo Beef (근내지방도가 높은 수입 등심육과 한우육의 육질특성 비교)

  • Hwang, I.H.;Park, B.Y.;Cho, S.H.;Kim, J.H.;Lee, J.M.
    • Journal of Animal Science and Technology
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    • v.46 no.4
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    • pp.659-666
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    • 2004
  • This study was conducted to assess objective and subjective meat quality traits for imported chilled beef with a high degree of marbling in longissimus muscle with reference to Hanwoo beef Muscle samples of four Wagyu, four Angus, four Hanwoo grade 1, and three Hanwoo grade 3 were purchased from a commercial beef market. The meats had intramuscular fat content of approximately 22, 8, 13 and 4%, and aged for 31, 71, 14 and 14 days, respectively. Imported beef showed a significantly(P<0.05) lower WB-shear force than Hanwoo. However, the instrument measurement did not reflect sensory tenderness and juiciness, which were similar between the four groups. On the other hand, Hanwoo beef showed significantly(P<0.05) favorable flavor intensity. This was likely an indication of more a desirable eating quality for Hanwoo beef, regardless of the level of intramuscular fat content. Discriminant functions of C18: 0, C18: In-7, C18: In-9, C20: 3n-6, C20 : 4n-6 and total n-3 polyunsaturated fatty acids classified the domestic and foreign beef products at 100%, despite a noticeable difference between two groups existed only in C18:0. Principle component analysis indicated that subjective flavor intensity was negatively related to C18: 0 and C18: ln-7. The result indicated that C18: 0 could be a possible candidate fatty acid for difference in flavor intensity between two beef groups. The current study demonstrated that the domestic product was more acceptable for Korean consumers. However, it was not identified whether the result was associated with breed, feeding regime, or ageing time. Further studies are required for breed specification in terms of sensory characteristics and consumer preference.