• Title/Summary/Keyword: problem analysis

Search Result 16,411, Processing Time 0.04 seconds

Trend of Physical Modelling For Ground Subsidence And Study of Its Application (지반함몰 모형실험 연구동향 및 적용방안 고찰)

  • Jeong, Seong-Yun;Jeong, Yeong-Hoon;Kim, Dong Soo
    • Journal of Korean Society of Disaster and Security
    • /
    • v.10 no.1
    • /
    • pp.1-10
    • /
    • 2017
  • Recently, increasing cases of ground subsidence in the urban area has become social issue, and related bill has been passed. Ground subsidence occurs through complex combination of various factors, and numerical analysis of this problem is limited thereby. This is why verification of ground subsidence mechanism has been conducted through physical modelling. Previous researches has been focused on modelling ground subsidence caused by utility pipe defects, and there has been insufficient physical modelling study on ground subsidence caused by various reasons such as groundwater flow and excavation activity. Also, most previous physical modelling studies were performed in 1g condition, which cannot take the in-situ stress condition into the evaluation of the ground subsidence mechanism. Therefore, in this study, physical modelling techniques to simulate various conditions is discussed by studying the previous researches on the ground subsidence mechanism through physical modelling. Also, centrifuge modelling test is suggested in this study as the technique to perform more reliable evaluation of ground subsidence mechanism. Lastly, this study suggests to apply the techniques used in the evaluation of ground subsidence mechanism into Ground Stability Assessment.

A Study on the Problem of Application of Seismic Performance Reinforcement Method for Urban Railways Case of Fiber and Rigid Reinforcement (섬유 및 강성 보강재료 기반 도시철도 내진성능 보강공법적용의 문제점 연구)

  • Ha, Kyoung Hwa;Park, Jae Yil;Kang, Hwi Jin
    • Journal of Korean Society of Disaster and Security
    • /
    • v.13 no.1
    • /
    • pp.13-23
    • /
    • 2020
  • In 2005, Urban railway seismic design was introduced in Rep. Of Korea, and many studies on seismic performance evaluation and reinforcement methods were conducted. In accordance with the Enforcement Decree of the Earthquake Disaster Countermeasures Act issued in March 2009, during April 2010 to October 2013, some of local governments established detailed evaluation and reinforcement measures for seismic performance of the urban railway underground structure. Afterwards, the seismic performance reinforcement of the existing urban railway structures was conducted for the sections that a long period of used until the end of 2018, and the reinforcement works are carried out by various methods using the previously studied methods. However, various reinforcing materials and construction methods using have been studied, but the classification research on the construction methods currently applied to reinforcement construction of urban railways is insufficient. The purpose of study is to analysis the cases currently applied to seismic reinforcement construction and to show the characteristics of each construction method, the reasons for its application and problems.

Analytical method of New POPs in environmental samples (환경 중 신규 POPs 분석방법 고찰)

  • Shin, Sun-Kyoung;Park, Jin-Soo;Kang, Young-Yeul;Lee, Su-Young;Chun, Jin-Won;Kim, Dong-Hoon;Yeon, Jin-Mo
    • Analytical Science and Technology
    • /
    • v.23 no.2
    • /
    • pp.128-137
    • /
    • 2010
  • The purpose of this study is to set up the analytical method of new persistent organic pollutants (POPs) such as chlordecone, endosulfan, ${\alpha}$-HCH, ${\beta}$-HCH, ${\gamma}$-HCH. The analytical methods for these compounds listed as new POPs by the Stockholm Convention need to be newly established. Therefore, we proposed the analytical method for 5 organic chlorinated pesticides (OCPs) and then applied the analytical method to environmental samples. To do this, the pre-treatment such as florisil and activated carbon cleanup process in the Korean official method for classic POPs had been reviewed. All of compounds except chlordecone were pre-treated simultaneously with reviewed cleanup process and detected by GC/MS and HRGC/HRMS respectively. There is a problem that chlordecone could not get a high sensitivity by GC analysis, but in this study GC/MS method was proposed.

Wall-Droplet Interaction Modeling and Comparative Study on Deformation Models for the Improvement of Icing Analysis Under SLD Conditions (SLD 조건에서 착빙 해석 정확도 개선을 위한 Wall-Droplet Interaction 수치 모델링 및 Deformation 모델 비교 연구)

  • Bae, Jinkyu;Yee, Kwanjung
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.48 no.4
    • /
    • pp.255-267
    • /
    • 2020
  • Under SLD conditions, due to the large size of droplets, physical phenomena such as wall-droplet interaction and deformation have a significant effect on the icing process. Accordingly, many studies have been conducted in order to computationally simulate SLD effects. As one of the efforts, post-processing method have been proposed to describe wall-droplet interaction effect, which modified collection efficiency using Wright model. However, since the model doesn't properly consider the wall condition, it still overestimated collection efficiency and impingement limit. To solve this problem, impingement areas were divided into 3 different regions, and the post-processing method was introduced with the new wall-droplet interaction model developed based on Bai and Gosman rebound model. In order to consider the effect of deformation, the most suitable model was selected by comparing the deformation models used in the various icing codes. As a result, the modified post-processing method showed improved accuracy in predicting the impingement limits and collection efficiency by further estimating mass flux loss due to rebound, and it was observed that the result was the closest to the experimental data when the deformation effect was included by using Wiegand model.

A Study on the Elements of Character in the Elementary Mathematics Textbooks Based on the 2009 Revised Curriculum -Focused on the 3rd and 4th Grades- (2009 개정 수학 교과용 도서의 인성 요소 분석 -3, 4학년을 중심으로-)

  • Park, Yongjun;Park, Mangoo
    • Journal of Elementary Mathematics Education in Korea
    • /
    • v.19 no.4
    • /
    • pp.545-561
    • /
    • 2015
  • The purpose of this study was to analysis how the elements of character are reflected in the 3rd and 4th grade elementary mathematics textbooks based on the 2009 revised curriculum. This study focused on the elements of character in the 3rd and 4th grade mathematics textbooks. The researchers analyzed the elements of character in the students' mathematics textbooks and teacher's guide books. In particular, they analyzed how those elements of character are reflected in those books. Findings of this study are as follows. First of all, the elements of character were founded in the most of units on the 3rd and 4th grade mathematics textbooks, but they were biased to the specific elements of character. Second, the resources using related with character vary in the textbooks. As methods of character education, connections of elements of character with mathematical concepts, broader view of the world, or problem solving are appeared. From the results of the research, we suggest the followings. We need to set the teacher's roles in character education. Mathematics textbooks should include various elements of character for effective character education. In addition to development of quality materials for character education in mathematics education, teacher education programs should include character education in mathematics education.

An Analysis on the Actual Conditions of the Mathematical Misconceptions Held by the Gifted Education Learners (수학영재교육 대상자의 수학용어에 대한 오개념 실태 조사)

  • Nam, Seung-In
    • Journal of Elementary Mathematics Education in Korea
    • /
    • v.15 no.1
    • /
    • pp.179-198
    • /
    • 2011
  • The understanding of mathematical concepts should be backed up on a constant basis in oder to grow problem-solving skills which is one of the ultimate goals of math education. The purpose of the study was to provide readers with the information which could be considered valuably for the math educators trying both to prevent mathematical misconceptions and to develop curricular program by estimating the actual conditions and developing backgrounds of the mathematical misconceptions held by the gifted education learners. Accordingly, this study, as the first step, theoretically examined the meaning and the developing background of mathematical misconception. As the second step, this study examined the actual conditions of mathematical misconceptions held by the participant students who were enrolled in the CTY(Center for Talented Youth) program run by a university. The results showed that the percentage of the correct statements made by participant students is only 35%. The results also showed that most of the participant students belonged either to the level 2 requiring students to distinguish examples from non-examples of the mathematical concepts or the level 3 requiring students to recognize and describe the common nature of the mathematical concepts with their own expressions based on the four-level of concept formulation. The causes could be traced to the presentation of limited example, wrong preconcept, the imbalance of conceptual definition and conceptual image. Based on the estimation, this study summarized a general plan preventing the mathematical misconceptions in a math classroom.

  • PDF

The Effect of Field-Based Participation Design on Agricultural Direct Sales Facilities: Process Change of Awareness on Participant (농특산물 직거래판매시설에 관한 현장중심의 참여디자인 효과: 참여자의 의식변화를 중심으로)

  • Seo, Aeeun;Hong, Jungpyo;Ha, Eunyoung;Chae, Hyesung
    • Science of Emotion and Sensibility
    • /
    • v.21 no.1
    • /
    • pp.165-176
    • /
    • 2018
  • A demand for user's participation in the designing process, which is called the participation design, is increasing with social change. Practically, however, there is lack of researches on the improvement of the problem in actual design development and participation design effect. In order to understand the field-based participation design effect in view of user's change of awareness on participation design, this study carried out a survey on the change of awareness through a design workshop in which all stakeholders have participated on the subject of agricultural direct sales facilities as a part of participation design programs. Many references were reviewed first to understand the participation design principles and their current research trend. Next, the questionnaire was developed using an effectiveness verification model for an effective analysis. A design workshop as one of the participation design programs was organized and applied for the field response. In order to analyze the effect, the survey on participants' change of awareness was carried out before and after the program. The survey questionnaires were about motivation, knowledge, recognition, function, and participation and asked the design study graduates. The participation design effect was supplemented by additional open questions. As a consequence, the participants in the participation design program showed the noticeable effect in knowledge and function about the agricultural direct sales facilities. It was found that they were also highly satisfied with the participation design result and they recognized an importance of collaboration. This study also showed that a sufficient time schedule considering agricultural village life should be given for a smooth operation of the program and also a working environment is necessary for designing work.

Biological characterization of Tenacibaculum maritimum isolated from cultured olive flounder in Korea and sensitivity against native plant extracts (한국의 양식넙치에서 분리한 Tenacibaculum maritimum의 특성과 자생식물 추출물에 대한 감수성)

  • Jang, Yeoung-Hwan;Jeong, Joon-Bum;Yeo, In-Kyu;Kim, Ki-Young;Harikrishnan, Ramasamy;Heo, Moon-Soo
    • Journal of fish pathology
    • /
    • v.22 no.1
    • /
    • pp.53-65
    • /
    • 2009
  • Tenacibaculum maritimum (formerly Flexibacter maritimus) is the aetiological agent of an ulcerative and necrotic disease commonly called tenacibaculosis in marine fish. Tenacibaculosis is an economically important disease in a great variety species in Jeju Island cultured fish and leading to this pathogen initially affected by skin, mouth, fins, tail causing severe necrotic and ulcerative lesions on the body surface. In the present study, A-7 strain was isolated from Paralichthys olivaceus showing symptoms of tenacibaculosis and identified as T. maritimum by morphological, biochemical and molecular biological analysis. T. maritimum A-7 is experimentally infected through immersion route in Paralichthys olivaceus which the disease outbreaks in land-based fish tanks of Jeju Island. Up to data a number of treatments proposed for the tenacibaculosis outbreaks are based on the immersion administration of drugs in tank. Oxytetracycline is the most widely used disinfectants in fish farms. However, most of fish farms manager and consumers have expressed concern as bioaccumulation in tissue and its environmental. In addition, this antimicrobial compounds is expensive in fish farmers. The overcome of this problem is desired the application of natural plant derived products. To obtain as 70% EtOH extract antimicrobial compounds against tenacibaculosis from 35 species of Jeju Island native plants were screened for antimicrobial activity against T. maritimum. In the present study were identified most of the plant extracts were better antimicrobial activity against T. maritimum.

A Systematic Review on Prevention and Treatment of Nipple Pain and Fissure: Are They Curable?

  • Niazi, Azin;Rahimi, Vafa Baradaran;Soheili-Far, Sina;Askari, Nafiseh;Rahmanian-Devin, Pouria;Sanei-Far, Zahra;Sahebkar, Amirhossein;Rakhshandeh, Hassan;Askari, Vahid Reza
    • Journal of Pharmacopuncture
    • /
    • v.21 no.3
    • /
    • pp.139-150
    • /
    • 2018
  • Averagely 80% to 90% of breastfeeding women experience the nipple pain and fissures. The important factor for successful breastfeeding is to treat this problem. This study has done as a review with the aim of analysis of the clinical trials in the field of the prevention and treatment of the nipple fissures and pain due to the importance of breastfeeding. For this purpose, the key words of sore, nipples, fissure, trauma, wound, prevention, treatment, therapeutics, therapy, clinical trial, breastfeeding and their Persian synonyms and all of their possible combinations were searched in the national databases: SID and Iran Medex and Magiran, and in the international databases: PubMed, Scopus, Medline, Science direct by May 2017. The Jadad criterion was used to assess the quality of the articles and the articles with a score of 3 or more were included in this study. Finally, 48 clinical trials were reviewed that 17 of them (sample size 1801) scored 3 or more based on the Jadad criterion. Seven articles were also in the non- drug treatment group (sample size 491) and 2 articles in the drug treatment group (sample size 337) and 8 articles in the herbal treatment group (sample size 973).The results show that menthol and warm water compress as well as teaching the correct breastfeeding methods are effective treatments to prevent and treat the nipple pain and fissures. Moreover, applying the herbal medicine for prevention and treatment of the issues raised from breastfeeding may have beneficial such as Aloe vera, Portulaca olearacea. However, more studies with a great methodology are necessary to obtain more accurate evidence.

Control Method of Habitat Density of Limnoperna fortunei in the Enclosed Facility of Water Supply Pipeline (폐쇄공간 송수관로내 민물담치의 서식밀도 조절방법)

  • Shin, Jae-Ki;Chong, Sun-A;Noh, Joonwoo;Kim, Youngsung;Hwang, Soon-Jin
    • Korean Journal of Ecology and Environment
    • /
    • v.47 no.3
    • /
    • pp.219-224
    • /
    • 2014
  • This study was conduct to the reduction and elimination of Limnoperna fortunei that problem in the facilities and water supply pipeline is done to review proposals for the controls. In order to effectively removal the larva and the adult of that, chlorination and being used to an existing method is to be commended. The water temperature of Limnoperna fortunei spawning season was ranged 16 to $17^{\circ}C$ during May to early November. A chlorination of this period is appropriate in order to control a larva. However, existing in the attached young and old shell at the same time consistently been deemed to apply, because it must be taken into account. The range of concentration of chlorination to control the biomass for Limnoperna fortunei was from 0.5 to 1.0 ppm. Proliferation attached to the mitigation or appropriate technology to solve the domestic situation the priorities of the choice of a more urgent. Also, the monitoring of water temperature and larva will constantly to be done. And development of larva monitoring method as well as after chlorine treatment is effective analysis needed. Finally, we are expecting to good use in validating the results presented in this study.