• Title/Summary/Keyword: a longitudinal case study

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A Study on the Longitudinal Strength of the Ship Hull(I) (선체 종강도에 관한 연구(I))

  • 고윤섭
    • Journal of the Korean Institute of Navigation
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    • v.8 no.2
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    • pp.43-50
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    • 1984
  • When the static load is applied to the ship's hull the deflection due to the bending moment from longitudinal direction has not been considered in the usual calculation of maximum bending moment. In fact, however, the deflection of ship's hull must be affected by the above-stated bending moment, and in this case the value of the maximum bending moment would be lessened in comparision with the result of usual calculation. In this paper, the author at first calculated the difference between the two values in case of rectangular barge, and suggested a practical criterion of longitudinal strength.

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A Case Study on Business Continuity following the Establishment of a Soho Fashion Shopping Mall: Longitudinal Research (소호패션쇼핑몰 창업 후 사업지속에 대한 사례연구: 종단적 연구를 중심으로)

  • Mi Young Son
    • Human Ecology Research
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    • v.62 no.1
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    • pp.1-13
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    • 2024
  • This study analyzed the current operational status, business continuity, and business continuity strategies of 11 Soho fashion shopping malls through a longitudinal case study (2019/2020 and 2022/2023). The aim was to determine how Soho fashion shopping malls are continuing their business having been successfully established in the fiercely competitive current online fashion market. Regarding changes in shopping mall operation status, all cases displayed changes in items, distribution channels, marketing channels, core values, and profit structures. After establishing the businesses, a crisis arose due to the COVID-19 pandemic, leading to difficulties in creating new customers. Moreover, there was excessive business expansion, resulting in saturation of the online platform store market. This meant companies were experiencing reduced sales (5) or difficulties in maintaining their business (3). However, there were differences in the direction of overcoming the crisis and continuing or converting the business. These revealed that to continue the business after successful establishment of an online fashion shopping mall, it is essential to have the expertise of entrepreneurs, work performance, and marketing ability, as well as differentiation capabilities such as product power and management strategy and core competitiveness that provides a relative advantage over other shopping malls. Customized government support at the level of the start-up ecosystem is also essential for the survival and business continuity of a SOHO online fashion shopping mall with poor human and material resources.

A Case Report on Ossification of Posterior Longitudinal Ligament Treated by Korean Medicine: Focusing on Chuna Therapy (경추간판 장애 및 척수병증을 동반한 후종인대골화증 환자에 대한 한의 복합 치료 1례 증례보고: 추나 요법을 중심으로)

  • Hong, Min-Woo;Kim, Jae-Kyoun;Park, Min-Jung;Yoon, Young-Heum;Kim, Su-Yong;Kim, Nam-Kwen
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.15 no.1
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    • pp.135-145
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    • 2020
  • Objectives : This study reports the clinical case of a patient diagnosed with ossification of the posterior longitudinal ligament treated with Korean Medicine focusing on Chuna therapy. Methods : The patient was treated by a doctor from July 18th, 2019 to November 28th, 2019. The patient was diagnosed with ossification of the posterior longitudinal ligament based on magnetic resonance imaging results and was recommended to undergo surgery at another hospital. The primary complaint of the patient was left neck pain, left arm sensation, right leg sensation, and right leg loss of strength. The doctor treated the patient with Chuna therapy, acupuncture, cupping, herbal medicine, and pharmacopuncture. The effect of treatment was evaluated using visual analogue scale, neck disability index, pain rating score and Japanese Orthopedic Association score. Spurling, compression, and distraction tests were utilized. Results : Visual analogue scale decreased from 10 at the arm and 10 at the leg to 1 and 2, respectively. Neck disability index decreased from 25 to 11, pain rating score decreased from 66 to 1, and Japanese Orthopedic Association score recovered from 12 to 17 points. In addition, positive spurling test, compression test, and distraction test all improved to negative. Conclusions : Korean medicine treatment can be effective for ossification of the posterior longitudinal ligament patients, even when surgery is recommended. Further clinical studies, such as case series and case-control studies, are required to verify these findings.

Plastic hinge length of circular reinforced concrete columns

  • Ou, Yu-Chen;Kurniawan, Raditya Andy;Kurniawan, Dimas Pramudya;Nguyen, Nguyen Dang
    • Computers and Concrete
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    • v.10 no.6
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    • pp.663-681
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    • 2012
  • This paper presents a parametric study of the plastic hinge length of circular reinforced concrete columns using a three-dimensional finite element analysis method, and using the Taguchi robust design method to reduce computational cost. Parameters examined include the longitudinal reinforcing ratio, the shear span-to-depth ratio, the axial force ratio and the concrete compressive strength. The study considers longitudinal reinforcement with yield strengths of 414 MPa and 685 MPa, and proposes simplified formulas for the plastic hinge length of circular reinforced concrete columns, showing that increases in plastic hinge length correlate to increases in the axial load, longitudinal reinforcing and shear span-to-depth ratios. As concrete strength increases, the plastic hinge length decreases for the 414 MPa case but increases for the 685 MPa case.

Mobility and Early Study Abroad as Transnational Migration: Categorization of Korean ESA in Singapore through a Follow-up Longitudinal Case Study (초국적 이주로서의 조기유학 : 싱가포르의 한국인 조기 유학생 추적 조사를 통한 이동성(mobility) 유형화)

  • KIM, Jeehun
    • The Southeast Asian review
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    • v.24 no.2
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    • pp.207-251
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    • 2014
  • This study explores the mobility patterns of Korean Early Study Aborad (ESA, hereafter) students in Singapore through a follow-up longitudinal case study, which was initially conducted about five years before this study. This study takes up transnational migration approach, focusing on family strategies and mobilization, which steered their mobility. Interviews with seven original families as well as 7 families additionally recruited in Singapore in 2012 were collected and analyzed by NVivo 9. In short, this study found that transnational mobility is composed of mobilities at global, regional and local levels. There were four types of mobilities; continuation of stay in Singapore, move from a third county to Singapore, return to Korea, and, what this research calls, fluid mobility. Examining the process of these mobilities shows that we need to consider at least three factors (performance of children's schooling; change of family circumstances; context of reception for both Singapore and Korea) as basic backgrounds. On this basis, the interplay between the context of receptions when aspirations for children's advancement by these transnational families made either facilitate or constrain their mobilities: contexts of Singapore and Korea may play a role of hurdle or trampoline. Also, local context of Singapore largely facilitate mobilities of Korean ESA families at both local and global levels.

Web bend-buckling strength of plate girders with two longitudinal web stiffeners

  • Kim, Byung Jun;Park, Yong Myung;Kim, Kyungsik;Choi, Byung H.
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.383-397
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    • 2019
  • More than one longitudinal web stiffener may be economical in the design of plate girders that have considerably high width-to-thickness ratio of webs. In this study, the bend-buckling strength of relatively deep webs with two horizontal lines of flat plate-shaped single-sided stiffeners was numerically investigated. Linear eigenvalue buckling analyses were conducted for specially selected hypothetical models of stiffened web panels, in which top and bottom junctions of a web with flanges were assumed to have simply supported boundary conditions. Major parameters in the analyses were the locations of two longitudinal stiffeners, stress ratios in the web, slenderness ratios and aspect ratios of web panels. Based on the application of assumptions on the combined locations of the two longitudinal web stiffeners, simplified equations were proposed for the bend-buckling coefficients and compared to the case of one longitudinal stiffener. It was found that bend-buckling coefficients can be doubled by adopting two longitudinal stiffeners instead of one longitudinal stiffener. For practical design purposes, additional equations were proposed for the required bending rigidity of the longitudinal stiffeners arranged in two horizontal lines on a web.

A Method of Compounding Application of Longitudinal Grade and Superelevation on Left Curved Section in Arterial for Preventing Hydroplaning (간선도로 좌곡선부 전후구간 수막현상 방지를 위한 종·횡단경사 조합 적용방안)

  • Jung, Ji Hwan;Oh, Heung Un
    • International Journal of Highway Engineering
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    • v.17 no.1
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    • pp.105-118
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    • 2015
  • PURPOSES : This study aims to evaluate the road safety of the super-elevation transition section of a left turn curve and suggest the minimum longitudinal grade of a super-elevation transition section to be used before and after a left curved section. METHODS : We evaluated the road condition by means of the safety-criterion-evaluation method involving side friction factors, and then solve the problem by introducing the minimum longitudinal grade criterion based on conditions described in the hydraulics literature. RESULTS : It was calculated that when a road satisfies hydroplaning conditions, the difference between side friction assumed and side friction demanded is less than -0.04. In this case, the safety criterion for the condition is unsatisfied. Conversely, when a road is in a normal state under either wet or dry conditions, it was calculated that the difference between side friction assumed and side friction demanded is more than 0.01. Thus, the safety criterion for this condition is found to be satisfied. After adjusting the minimum longitudinal grade applied to a super-elevation transition section, the hydroplaning condition can be eliminated and the safety criterion can be met for all sections. CONCLUSIONS : It is suggested that a minimum longitudinal grade should be provided on super-elevation transition sections in order to prevent hydroplaning.

A Case Study of Assessment of the Ecological Connectivity of Cross Sectional Structures in the Flowing Stream (하천 내 횡단구조물에 대한 수생태 연속성 평가 방안에 대한 연구)

  • Choi, Heung Sik
    • Ecology and Resilient Infrastructure
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    • v.7 no.4
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    • pp.320-326
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    • 2020
  • The present study aimed to assess the longitudinal connectivity owing to migrant characteristics of the target fish. The study area was Wonju-cheon Stream, and the target species were Zacco platypus and Minnows. The HEC-RAS model was used for the computation of the flow, and the ICE (Information sur la Continuite Ecologique) method was used to analyze the longitudinal connectivity. The longitudinal connectivity was assessed using the minimum overflow height, velocity, and depth of the cross sectional structure of a plunge pool and considering the swimming speed of the target fish. Simulation results indicated that the longitudinal connectivity scores for the Zacco platypus and Minnows were approximately 76 and 23, respectively.

A Case Study on the Application of Echelon Paving Method Using a 12m-Wide Screed Finisher on Flexible Airfield Pavements (광폭 Echelon 공법의 연성 활주로 포장 적용에 관한 사례 연구)

  • Jeon, Kook-Il;Choi, Heung-Sup;Bin, Cheol-Ho
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.353-356
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    • 2007
  • Asphalt pavements of the airport in service were monitored to construct new runway and taxiway and longitudinal cracks were found on the pavements. The sources of the longitudinal cracks were the low density which was caused by the longitudinal cold joint with asphalt Pavement constructions and the excessive loads of aircraft. Therefore, the echelon paving method using a 12m-wide screed finisher was used to eliminate longitudinal cracks. When the echelon paving is used, construction of the longitudinal joint is changed so that the compaction of the unconfined edge of the first lane is delayed until the second lane is placed. In conclusion, the use of this construction method results in the density of the longitudinal joint being equal to that of the adjacent mat.

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Effect of Longitudinal Reinforcement Ratios and Axial Deformation on Frame Analysis in RC Columns (기둥의 철근비와 축변형량이 보 해석에 미치는 영향 연구)

  • 장원석;민창식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.477-482
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    • 2001
  • This paper is to study the effect of longitudinal reinforcement ratios and axial deformation on the frame analysis in reinforced concrete(RC) columns and to investigate the effect of confined concrete core, the length-width ratio and longitudinal steel ratios on frame analysis in Concrete-Filled steel Tubular(CFT) columns. An equation if derived to evaluate the modulus of elasticity for core concrete. The 34 reference data have been collected for the purpose and are processed by the mean of a multiple regression analysis technique. The equation and longitudinal reinforcement ratios was applied to RC columns for structural analysis. Then, the difference of beam moment was identified. In general, the results of analysis was indicated reasonable differences in beam moment, in case of longitudinal reinforcement ratios applied to RC columns when compared with the plain concrete columns. In CFT columns the equation was also applied in order to the effect of confined concrete core on structural analysis. Beam moment was increased as volumetric ratio of lateral steel was decreased. The effect of longitudinal steel ratios was investigated in CFT columns and was confirmed beam moment variety. The result was appeared reasonable difference in beam moment as longitudinal steel was increased.

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