• Title/Summary/Keyword: External Force

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Structural Strength Evaluation for Development of a Vertical Transfer Device for a Personal Rapid Transit (PRT) Vehicle (PRT 차량용 수직이송장치의 개발을 위한 구조강도 평가)

  • Kang, Seok-Won;Um, Ju-Hwan;Jeong, Rag-Gyo;Song, Joon-Hyun
    • Transactions of the KSME C: Technology and Education
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    • v.3 no.3
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    • pp.165-173
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    • 2015
  • This paper presents numerical results of static structural stability analysis in development of a vertical transfer device of a PRT(Personal Rapid Transit) vehicle. The vertical transfer of a fully occupied vehicle operating on a road network is the first attempt, which is expected to contribute to overcome the limitations of conventional 2-dimensional operation mode. In particular, the vertical transfer apparatus designed based on vertical circulating conveyors is capable of continuous transfer without time delay so that it enables to accommodate a high traffic density. This system has been frequently used in a logistics field; however, it is essential to assess a structural integrity because an external force by a vehicle weight is exerted on the conveyors in the form of a concentrated load unlike a conventional logistic transport. In this study, prior to the production process, the structural performance of the pilot design in an early stage is numerically evaluated using the commercial finite element method (FEM) solver (i.e., $Ansys^{(R)}$).

Sensitivity Analysis of Sediment Transport Scaling Factors on Cross-Shore Beach Profile Changes using Deflt3D (해빈 단면의 지형변화 모의를 위한 Delft3D 내의 표사이동 관련 매개변수의 민감도 분석)

  • Yang, Jung-A;Son, Sangyoung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.6
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    • pp.493-500
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    • 2019
  • In this study, sensitivity analysis of sediment transport scaling factors in Delft3D-Morphology was performed to examine the effect those parameters on simulation results of cross-shore profile changes. For numerical experiments, one-year wave time series data which were observed in 2018 on the Maengbang coast in Gangwon prefecture were applied as external force. Bathymetric data observed in January and October of the same year were used as initial bathymetric data and annual bathymetric change data, respectively. The simulation performance of the model was evaluated based on the Brier Skill Score index for each part by dividing an arbitrary cross section within the calculation domain into the onshore and offshore parts. As a result, it was found thet the fBED variable has a slight effect on the simulation results. The fBEDW and fSUSW variables show good simulation performance in onshore part when the value less than 0.5 is applied and vice versa. Among the experimental conditions, the optimal combinations of variables are fBED = 1.0, fBEDW = 1.0, fSUSW = 0.1 for the onshore region and fBED = 1.0, fBEDW = 1.0, fSUSW = 0.5 for the offshore region. However, since these combinations were derived based on the observation data on Maengbang beach in 2018, users should be careful when applying those results to other areas.

The Recent Practice of Evaluation of Government-sponsored Research Institutes(GRIs) in Korea : From Retrospective to Forward-looking perspective (이공계 정부출연(연) 기관평가모형개발 및 적용사례 연구)

  • 이철원;현재호
    • Proceedings of the Technology Innovation Conference
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    • 1998.06a
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    • pp.131-163
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    • 1998
  • The interest in the evaluation of government-sponsored research institutes (GRIs) has increased markedly in Korea in 1990s; this is mainly because of the increasing needs 1) to improve the quality of R&D at GRIs, and 2) to reorient the GRIs' strategic position in Korean national innovation systems due to the enhancement of R&D capabilities of private companies and universities during last decade. As a first attempt to diagnose the managerial and strategic issues of GRIs, a Multi-Ministerial Evaluation Committee was established as an ad hoc task force under the Prime Minister's Office in 1991. According to the recommendations of the committee, the Ministry of Science and Technology (MOST) to which most of GRIs were affiliated, made it a rule to evaluate the annual performance of GRIs since 1992. This paper examines the recent experience of MOST's evaluation of Government-sponsored Research Institute in Korea. After several years'efforts of Science & Technology Policy Institute(STEPI) to build prospective evaluation systenL MOST decided to apply two supplementary approaches for the evaluation of GRIs; one is summative annual evaluation and the other is formative 3-year evaluation. The annual evaluation system that is designed as a temporary measure is to monitor and to guide the self-evaluation activities of GRIs. In the process of annual evaluation, MOST tries to minimize its direct involvement, and allows each GRI to develop self-evaluation system that is most appropriate for the unique characteristics of the institute. If there exist urgent issues under scrutiny, however, it can be incorporated and examined by a group of external experts as special issues in the annual evaluation system. The aim of 3-year evaluation is both to examine the past performance of each GRI and to investigate whether the strategic role of each GRI is viable in the future. Its major focus, however, lies not on auditing past performance but on strengthening future strategic position of each GRI. The MOST designates a group of evaluation experts with appropriate knowledge and competence as members of the General Evaluation Committee for one year. With the help of STEPI, a specialized research institute for R&D evaluation, the General Evaluation Committee develops methodology and procedures for the actual evaluation of GRIs. Based on the evaluation reports and recommendations from the General Evaluation Committee, the MOST develops various policy measures for strengthening GRIs.

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A study on the development and field application of SP-Rockbolt with high-strength steel pipe (고강도 강관을 적용한 SP-록볼트 개발 및 현장 적용을 위한 연구)

  • Shin, Hyunkang;Jung, Hyuksang;Ahn, DongWook
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.4
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    • pp.651-668
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    • 2017
  • For initial stability of the tunnel, the primary support, Shotcrete and rockbolt shall be placed in the most appropriate time. This is because the role of such support plays a vital role in long-term and short-term tunnel stability. In this study, the rock bolt is an important supporting system that receives the external pressure generated by the stress relaxation during tunnel excavation as axial force and transmits it to the shotcrete on the tunnel excavation surface. Until now, most of the materials of rock bolts have been used in the field, but there have been many problems such as uncertain quality of Chinese materials entering the market, poor packing due to falling down of rock bolts when filled with mortar, and corrosion due to water. Therefore, in this study, we have developed a high strength steel pipe rock bolt using Autobeam material to solve and improve various problems of existing rock bolts. In order to evaluate the performance of the developed bolt, field tests were carried out and the existing mortar filler in order to improve the performance of the rock bolt, the design and construction criteria were studied and the results were included in this paper.

Cognitive-pragmatic Language Ability Assessment Protocol for Traumatic Brain Injury(CAPTBI): Reliability and Validity (외상성 뇌손상 환자의 인지-화용언어 능력 평가도구 개발을 위한 신뢰도 및 타당도 연구)

  • Lee, Mi-Sook;Kim, HyangHee
    • The Journal of the Korea Contents Association
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    • v.13 no.2
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    • pp.370-377
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    • 2013
  • Traumatic brain injury(TBI) is a brain damage caused by an external physical force. TBI patients have disturbances of functioning including attention, memory, reasoning,, executive function, and pragmatic language. The aim of this study was to develop the cognitive-pragmatic language ability assessment protocol for traumatic brain injury(CAPTBI) and to evaluate reliability and validity. This study was also conducted to investigate domains that contributed to differentiate between the normal and TBI groups. The CAPTBI data were obtained from 226 normal adults and 62 TBI patients(mean age=$43.95{\pm}11.92$, $46.37{\pm}11.87$, M:F=110:116, 48:14). The CAPTBI had high item internal consistency, test-retest reliability, construct validity, and concurrent validity. The normal group performed significantly better than the TBI group in all domains of the CAPTBI and the separate scores for 9 domains. All 9 domains were found to be significant variables to discriminate between the two groups. The most powerful variable was executive function followed by memory, organization, pragmatic language, problem-solving, attention, orientation, reasoning, and visuoperception in order. The CAPTBI could discriminate between the two groups accurately by 95.5%. This result demonstrated that 97.3% of normal adults and 88.7% of TBI patients could be discriminated by CAPTBI. In conclusion, The CAPTBI is appropriate for evaluating and identifying cognitive-pragmatic language disorders in TBI patients.

Development of Abrasive Film Polishing System for Cover-Glass Edge using Multi-Body Dynamics Analysis (다물체 동역학 해석을 이용한 커버글라스 Edge 연마용 Abrasive Film Polishing 시스템 개발)

  • Ha, Seok-Jae;Cho, Yong-Gyu;Kim, Byung-Chan;Kang, Dong-Seong;Cho, Myeong-Woo;Lee, Woo-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.10
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    • pp.7071-7077
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    • 2015
  • In recently, the demand of cover-glass is increased because smart phone, tablet pc, and electrical device has become widely used. The display of mobile device is enlarged, so it is necessary to have a high strength against the external force such as contact or falling. In fabrication process of cover-glass, a grinding process is very important process to obtain high strength of glass. Conventional grinding process using a grinding wheel is caused such as a scratch, chipping, notch, and micro-crack on a surface. In this paper, polishing system using a abrasive film was developed for a grinding of mobile cover-glass. To evaluate structural stability of the designed system, finite element model of the polishing system is generated, and multi-body dynamic analysis of abrasive film polishing machine is proposed. As a result of the analysis, stress and displacement analysis of abrasive film polishing system are performed, and using laser displacement sensor, structural stability of abrasive film polishing system is confirmed by measuring displacement.

A Study on Estimation of Levee Safety Map for Determining the Priority of River Maintenance (하천 유지관리 우선순위 결정을 위한 제방안전도맵 산정방법 연구)

  • Yoon, Kwang Seok;Kim, Sooyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.12
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    • pp.17-25
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    • 2017
  • Owing to recent climate change, the scale of rainfall tends to increase gradually and the risk of flooding has increased. Therefore, the importance of improving the levee management and disaster response is increasing. Levee management in Korea is carried out at the level of damage recovery after the occurrence of damage. Therefore, it is necessary to develop a technology for predicting and managing the levee safety with proactive river management. In this study, a method to estimate the safety against erosion and overflow was suggested. A map of levee safety that can be used as basic data is presented by displaying the levee safety on the map. The levee erosion safety was calculated as the ratio of the internal and external force for each shore type. The levee overflow safety was calculated as the ratio of the maximum conveyance and design flood. The maximum conveyance was a discharge when the level of the river was equal to the level of the levee crown. The levee safety was classified into 5 grades: very safe, safe, normal, dangerous, and very dangerous. As a research area from downstream of Nam River Dam to Nakdong River Junction, the levee safety against erosion and overflow was estimated for all levees and all cross-sections of the river. The levee safety was displayed on a map using GIS. Through the levee safety map as a result of this study, the levee safety can be observed intuitively. Using the levee safety map, a maintenance plan for a river can be easy to build. This levee safety map can be used to help determine the priority of investment for efficient budget used.

Competitive Advantages and Growth Characteristics of Korea's Tourism Industry - Comparative Analysis with Northeast Asian Countries by Using Shift-Share Method (우리나라 관광산업의 경쟁우위와 성장 특성 - 변이할당분석방법을 이용한 동북아시아 지역 국가들과의 비교 분석)

  • Kim, Young-Joon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.3
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    • pp.370-379
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    • 2020
  • This study examined the growth characteristics and competitive advantages of Korea's tourism industry compared to other Northeast Asian countries using the Balassa Indices and Shift-Share method. The analysis results showed that the growth of Korea's tourism industry over the past decade was due mainly to external factors, such as the growth of the global economy and the expansion of the tourism sector, while the role of growth momentum of the tourism industry itself was insignificant. Employment in Korea's tourism industry has shown relatively higher increasing rates compared to the rates of the total amount of sales and value-adding. This appears to be caused by the decreased absorption of the labor force in the tourism industry due to the overall capacity of job creation. (Ed note: This sentence was unclear. Please check the edits.)The competitive advantage of Korea's tourism industry has been strengthened over the past decade, but it is still inferior to other countries. The travel account balance showed that the economic size of the Chinese tourism sector had grown rapidly over the past decade, but the competitive advantage of the sector has been weakened. On the other hand, the economic size of the Japanese tourism sector has shown sluggish growth, while its competitive advantage has been strengthened significantly.

Out-of-plane Deformation Measurement of Spherical Glasses Lens Using ESPI (ESPI를 이용한 구면 안경렌즈의 면외 변형 측정)

  • Yang, Seung-Pill;Kim, Kyoung-Suk;Jang, Ho-Sub;Kim, Hyun-Min
    • Journal of Korean Ophthalmic Optics Society
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    • v.12 no.4
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    • pp.77-81
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    • 2007
  • The spherical lens is typically classified by the refractive power into two groups such as (+) diopter lens and (-) diopter lens. The deformation occurred by the external force that is applied to a lens is caused by the increase or the decrease in the diopter of a lens. In this paper, the deformation of the lens was quantitatively measured by using ESPI (Electronic Speckle Pattern Interferometry) which have been used in the optical measurement field for past few years. ESPI has an advantage that the deformation of an object can be measured precisely by using coherence of the light. The experiment was carried out to the totally 16 types of plastic lens. It was confirmed that the deformation was decreased by increasing the diopter of the lens when same displacement was applied to the lens in case of (+) diopter lens and was increased by decreasing the diopter of the lens in case of (-) diopter lens. Also, it was found that the deformation of (+) diopter lens is less than that of (-) diopter lens. Therefore, with these results, it is expected that the possibility of the quantitative measurement for variation of the optical defect caused by the deformation of a lens when the deformation is occurred to the various types of the lens can be presented and that the application in the lens industrial field can be performed.

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A Study on the Roles and Revision of eUCP for Global Electronic Trading (글로벌 전자무역의 실현을 위한 eUCP의 역할과 개정방안)

  • Choi, Seok-Beom;Hong, Sung-Kyu
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.18
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    • pp.105-134
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    • 2002
  • In the Spring of 2000, the Banking Commission of the ICC decided to appoint a working group to draft a supplement to the UCP 500 to clarify the position regarding electronic presentation under a documentary credit. Provisions was drafted to supplement its existing rules for documentary credit, that is, UCP 500. These new provisions known as Supplement to UCP 500 for Electronic Presentation was approved by the ICC Banking Commission at the beginning of November 2001 and came in force as of 1 April 2002 The eUCP covers matters such as definitions of key terms such as electronic record, electronic signature, format, paper document, received. An eUCP Credit must specify the formats in which electronic records are to be presented and if not, electronic records may be presented in any format. Electronic records may be presented separately and need not be presented at the same time. The purpose of this paper is to understand the main substance of eUCP and to facilitate the introduction of electronic letter of credit by studying the problems and revision of eUCP and new electronic UCP. The main substances of eUCP are electronic address as place for presentation of electronic records, flexibility of the formats of electronic records to be presented, endowment of the notice of completeness of presentation to the beneficiary, one electronic record satisfying one or more originals or copies of an electronic record, the electronic records to be examined including the electronic record at the hyperlink to an external system or the referenced system, no remark as to the time period for the examination of documents. The Roles of eUCP are the Promotion of the Electronic Trade, the Supply of Basis on the Uniform Rules for Electronic Letter of Credit, the introduction of Electronic Trade Model. The characteristics of eUCP are a supplement to the UCP, no address of any issues relating to the issuance or advice of Credit electronically, independence of specific technologies and developing electronic commerce system, that is, Bolero Service. The Problems of eUCP are flexibility of format of electronic record, heavy burden on the side of banks, and the problems regrading the number of presentation, the notice of completeness of presentation, no provision in regard to the time to examine the electronic records, and representation of the electronic records. In the revision of eUCP to resolve the problems, the things to be taken into consideration are as follows; the designation of the format allowing the banks to examine electronically, prohibition of the paper documents, the development of the system receiving the electronic records, the addition of the reception notice on the side of the banks, the setting of the time to examine the electronic records, the construction of the backup system or the dual processing system.

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