• Title/Summary/Keyword: Mass-estimation

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Validation of a Robust Flutter Prediction by Optimization

  • Chung, Chan-Hoon;Shin, Sang-Joon
    • International Journal of Aeronautical and Space Sciences
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    • v.13 no.1
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    • pp.43-57
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    • 2012
  • In a modern aircraft, there are many variations in its mass, stiffness, and aerodynamic characteristics. Recently, an analytical approach was proposed, and this approach uses the idea of uncertainty to find out the most critical flight flutter boundary due to the variations in such aerodynamic characteristics. An analytical method that has been suggested to predict robust stability is the mu method. We previously analyzed the robust flutter boundary by using the mu method, and in that study, aerodynamic variations in the Mach number, atmospheric density, and flight speed were taken into consideration. The authors' previous attempt and the results are currently quoted as varying Mach number mu analysis. In the author's previous method, when the initial flight conditions were located far from the nominal flutter boundary, conservative predictions were obtained. However, relationships among those aerodynamic parameters were not applied. Thus, the varying Mach number mu analysis results required validation. Using an optimization approach, the varying Mach number mu analysis was found out to be capable of capturing a reasonable robust flutter boundary, i.e., with a low percentage difference from boundaries that were obtained by optimization. Regarding the optimization approach, a discrete nominal flutter boundary is to be obtained in advance, and based on that boundary, an interpolated function was established. Thus, the optimization approach required more computational effort for a larger number of uncertainty variables. And, this produced results similar to those from the mu method which had lower computational complexity. Thus, during the estimation of robust aeroelastic stability, the mu method was regarded as more efficient than the optimization method was. The mu method predicts reasonable results when an initial condition is located near the nominal flutter boundary, but it does not consider the relationships that are among the aerodynamic parameters, and its predictions are not very accurate when the initial condition is located far from the nominal flutter boundary. In order to provide predictions that are more accurate, the relationships among the uncertainties should also be included in the mu method.

Modelling land degradation in the mountainous areas

  • Shrestha, D.P.;Zinck, J.A.;Ranst, E. Van
    • Proceedings of the KSRS Conference
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    • 2003.11a
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    • pp.817-819
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    • 2003
  • Land degradation is a crucial issue in mountainous areas and is manifested in a variety of processes. For its assessment, application of existing models is not straightforward. In addition, data availability might be a problem. In this paper, a procedure for land degradation assessment is described, which follows a four-step approach: (1) detection, inventory and mapping of land degradation features, (2) assessing the magnitude of soil loss, (3) study of causal factors, and (4) hazard assessment by applying decision trees. This approach is applied to a case study in the Middle Mountain region of Nepal. The study shows that individual mass movement features such as debris slides and slumps can be easily mapped by photo interpretation techniques. Application of soil loss estimation models helps get insight on the magnitude of soil losses. In the study area soil losses are higher in rainfed crops on sloping terraces (highest soil loss is 32 tons/ha/yr) and minimal under dense forest and in irrigated rice fields (less than 1 ton/ha/yr). However there is high frequency of slope failures in the form of slumps in the rice fields. Debris slides are more common on south-facing slopes under rainfed agriculture or in degraded forest. Field evidences and analysis of causal factors for land degradation helps in building decision trees, the use of which for modelling land degradation has the advantage that attributes can be ranked and tested according to their importance. In addition, decision trees are simple to construct, easy to implement and very flexible in adaptations.

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Case Report of Verrucous Carcinoma Arising in Sacral Pressure Sore (천골욕창에 발생한 우췌양 암종 1례)

  • Jeong, Jaehoon;Heo, Chan Yeong;Kwon, Soon Sung;Baek, Rong Min;Minn, Kyeong Won
    • Archives of Plastic Surgery
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    • v.34 no.4
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    • pp.520-523
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    • 2007
  • Purpose: Verrucous carcinoma is a rare, low-grade and well-differentiated squamous cell carcinoma, representing as a warty tumor. Estimation of the incidence for cutaneous lesions is not available because they are rare. We describe a case of verrucous carcinoma, a rare type, complication of a chronic pressure ulcer of duration more than 15 years. Methods: A 17-year-old boy presented with a large lesion involving the sacral area, which had been neglected for about 15 years. He had a history of surgical extirpation 2 years ago, but not cured. Examination revealed a cauliflower-like mass arising from an irregularly oval-shaped tumor which was $6.0{\times}4.5cm$ in size with signs of infection and ulcer. The lesion involved the sacrococcygeal area, spreading to both medial gluteal regions. The perianal skin did not appear to be directly affected. Results: A preoperative punch biopsy revealed a extremely well differentiated verrucous carcinoma. There were positive results in immunohistochemistry in the items of p53, p63, Ki-67. An 'en-bloc' excision of the tumor with the clinically normal surrounding tissue was carried out. Reconstruction was achieved by local regional flap. Histopathological findings of the excised area fully confirmed the preoperative biopsy report. It remained free of recurrence for a period of about 8 months. Conclusion: We believe that in patients with buttock involvement, regardless of the extent of such tumors, surgical therapy should be considered as the first-choice of treatment as reconstruction can be performed without excessive impairment for the patient.

Estimation of Storage Capacity for CSOs Storage System in Urban Area (도시유역 CSOs 처리를 위한 저류형시스템 설계용량 산정)

  • Jo, Deok Jun;Lee, Jung Ho;Kim, Myoung Su;Kim, Joong Hoon;Park, Moo Jong
    • Journal of Korean Society on Water Environment
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    • v.23 no.4
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    • pp.490-497
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    • 2007
  • A Combined sewer overflows (CSOs) are themselves a significant source of water pollution. Therefore, the control of urban drainage for CSOs reduction and receiving water quality protection is needed. Examples in combined sewer systems include downstream storage facilities that detain runoff during periods of high flow and allow the detained water to be conveyed by an interceptor sewer to a centralized treatment plant during periods of low flow. The design of such facilities as stormwater detention storage is highly dependant on the temporal variability of storage capacity available (which is influenced by the duration of interevent dry periods) as well as the infiltration capacity of soil and recovery of depression storage. As a result, a continuous approach is required to adequately size such facilities. This study for the continuous long-term analysis of urban drainage system used analytical probabilistic model based on derived probability distribution theory. As an alternative to the modeling of urban drainage system for planning or screening level analysis of runoff control alternatives, this model have evolved that offer much ease and flexibility in terms of computation while considering long-term meteorology. This study presented rainfall and runoff characteristics of the subject area using analytical probabilistic model. This study presented the average annual COSs and number of COSs when the interceptor capacity is in the range $3{\times}DWF$ (dry weather flow). Also, calculated the average annual mass of pollutant lost in CSOs using Event Mean Concentration. Finally, this study presented a decision of storage volume for CSOs reduction and water quality protection.

Effect of Opening Partition Length on Helium-Air Exchange Flow (개구부 삽입부의 길이가 헬륨 및 공기의 치환류에 미치는 영향)

  • 강태일
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.2
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    • pp.192-200
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    • 1999
  • This paper describes experimental investigations of helium-air exchange flow through parti-tioned opening. Such exchange flow may occur following rupture accident of stand pipe in high temperature gas cooled reactor. A test vessel with a opening on top of test cylinder is used for experiments. An estimation method of mass increment is developed and applied to measure the exchange flow rate. A technique of flow visualization by Mach-Zehnder interferometer is provided to recognize the exchange flows. Flow measurements are made with partitioned opening for parti-tion rations $H_p/H_1$ in the range 0 to 1 where $H_p$ and $H_1$ are partition length and height of the open-ing respecticely. In the case of $H_p/H_1$ of 0 flow passages of upward flow of the helium and down-ward flow of the air within the opening are unseparated (bidirectional) and the two flows interact exchange flow rate is minimum through range of the partition ratios, Two flow zones i.e. separat-ed(unidirectional)flow zone and unseparated(bidirectional) flow zone exist with increasing the partition. length, The exchange flow rate increases with increasing the separated flow zone. It is found that a maximum exchange flow rate exists at $H_p/H_1$ of 1. As a result fo comparison of the exchange flow rates by changing the partition ration the fluids interaction in the unseparated zone is found to be an important factor on the helium-air exchange flow rate.

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Psychological, Physical and Genetic Traits of Sasang Typology (사상인(四象人)의 생리적 특성 연구)

  • Chae, Han;Hong, Moo-Chang;Bae, Hyun-Su;Shin, Min-Kyu
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.19 no.2
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    • pp.304-314
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    • 2005
  • The major concept of Sasang typology is that the disease susceptibility and drug response as well as physiological characteristics are presumed to be different depending on their Sasang types. Although characterizing fundamental basis of their traits are crucial in this research field, only pathological susceptibility and physical appearances were thoroughly studied. We evaluated their physiological characteristics by tapping psychological, physical and genetic traits of each Sasang types. After determining the Sasang type of one hundred three college students based on the Questionnaire for the Sasang Constitution Classification, the psychological, physical and genetic traits of each type were analyzed with the Myers-Briggs Type Indicator (MBTI), Bioelectrical Impedance Analysis and genetic polymorphism test, respectively. Each of the Sasang types showed significantly different profiles (Generalized estimation equation, coef=11.88, z=2.13, p=0.033), and could be distinctively classified based on their MBTI scores (discriminant analysis Wilks Lambda=0.611, df=8, chi-square=36.7, p<0.001). Subjects with the So-Eum type (Introversion and Judging) and the So-Yang type (Extroversion and Perceiving) showed contrasting psychological features, however they had similar anthropometric characteristics. Subjects with the Tae-Eum type showed bigger Body Mass Index ($R^2$=0.22, df=4, 74, F=5.07, p=0.001) and body shape compared to others. Although there were no significant differences in G-protein beta-3 subunit polymorphism, angiotensin-converting enzyme polymorphism and Methylenetetrahydrofolate reductase polymprhisms among groups with Sasang types, it was shown that the dopamine system could be one for genetic marker for Sasang typology. These results demonstrated distinctive and essential traits of Sasang typology using reproducible psychometric, anthropometric and genetic evaluations. We also found that the Sasang typology was a bio-psychological typology which could show trait-specific guideline for individualized medicine.

Performance Factor Analysis of Sensing-Data Estimation Algorithm for Walking Robots (보행 로봇을 위한 센서 추정 알고리즘의 성능인자 분석)

  • Shon, Woong-Hee;Yu, Seung-Nam;Lee, Sang-Ho;Han, Chang-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.11
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    • pp.4087-4094
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    • 2010
  • The sensor data which is measured by Quadruped robot is utilized to recognize the physical environment or other information and to control the posture and walking of robot system. In order to control the robot precisely, high accuracy of sensor data is required, most of these sensors however, belongs to expensive and low-durable products. Moreover, these are exposed excessive load operation in a field condition if it is applied to field robot system. This issue becomes more serious one when the robot system is manufactured as a mass product. As in this context, this study suggests a virtual sensor technology to alternate or assist the main sensor system. This scheme is realized by using back-propagation algorithm of neural network theory, and the quality of estimated sensor data could be improved through the algorithmic and hardware based treatments. This study performs the various trial to identify the effective parameters which effect to the quality and reliability of estimated sensor data and tries to show the possibility of proposed methodology.

Methane emission from municipal solid waste dumpsites: A case study of Chennai city in India

  • Srinivasan, Pavithrapriya;Andimuthu, Ramachandran;S.N., Ahamed Ibrahim;Ramachandran, Prasannavenkatesh;Rajkumar, Easwari;Kandasamy, Palanivelu
    • Advances in environmental research
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    • v.9 no.2
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    • pp.97-107
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    • 2020
  • The indiscriminate growth in global population poses a threat to the world in handling and disposal of Municipal solid waste. Rapid urban growth increases the production, consumption and generation of Municipal solid waste which leads to a drastic change in the environment. The methane produced from the Municipal Solid waste accounts for up to 11% global anthropogenic emissions, which is a major cause for global warming. This study reports the methane emission estimation using IPCC default, TNO, LandGEM, EPER and close flux chamber from open dump yards at Perungudi and Kodungaiyur in Chennai, India. The result reveals that the methane emission using close flux chamber was in the range of 8.8 Gg/yr-11.3 Gg/yr and 6.1Gg/yr to 9.1 Gg/yr at Kodungaiyur and Perungudi dump yard respectively. The per capita waste generation was estimated based on waste generation and population. The waste generation potential was projected using linear regression model for the period 2017-2050. The trend of CH4 emission in the actual field measurement were increased every year, similarly the emission trend also increased in IPCC default method (mass balance approach), EPER Germany (zero order decay model) where as TNO and Land GEM (first order decay model) were decreased. The present study reveals that Kodungaiyur dump yard is more vulnerable to methane emission compared to Perungudi dump yard and has more potential in waste to energy conversion mechanisms than compare to Perungudi dump yard.

Real Time SW Sizing Model for FP-Based Fintech Software Development Project (FP 기반의 핀테크 소프트웨어 개발 프로젝트 실시간 규모 산정 모델)

  • Koo, Kyung-Mo;Yoon, Byung-Un;Kim, Dong-Hyun
    • Journal of Convergence for Information Technology
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    • v.11 no.10
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    • pp.36-44
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    • 2021
  • Estimation on SW Sizing applied to fintech is very difficult, a task requiring long time, it is difficult for client companies and developer companies to accurately calculate the size of software development. The size is generally estimated based on the experience of project managers and the general functional scoring method. In this paper, propose a model that can be applied to fintech development projects by quantitatively calculating the required functions from the user's point of view, measuring the scale, and calculating the scale in real time. Through the proposed model, the amount of work can be estimated prior to development and the size can be measured, and the M/M and the estimated quotation amount can be calculated based on the program list by each layer. In future studies, by securing size computation data on existing the Fintech Project in mass, research on accurate size computation would be required.

Estimation of Mass Rapid Transit Passenger's Train Choice Using a Mixture Distribution Analysis (통행시간 기반 혼합분포모형 분석을 통한 도시철도 승객의 급행 탑승 여부 추정 연구)

  • Jang, Jinwon;Yoon, Hosang;Park, Dongjoo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.20 no.5
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    • pp.1-17
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    • 2021
  • Identifying the exact train and the type of train boarded by passengers is practically cumbersome. Previous studies identified the trains boarded by each passenger by matching the Automated Fare Collection (AFC) data and the train schedule diagram. However, this approach has been shown to be inefficient as the exact train boarded by a considerable number of passengers cannot be accurately determined. In this study, we demonstrate that the AFC data - diagram matching technique could not estimate 28% of the train type selected by passengers using the Seoul Metro line no.9. To obtain more accurate results, this paper developed a two-step method for estimating the train type boarded by passengers by applying the AFC data - diagram matching method followed by a mixture distribution analysis. As a result of the analysis, we derived reasonable express train use/non-use passenger classification points based on 298 origin-destination pairs that satisfied the verification criteria of this study.