• 제목/요약/키워드: dynamic period

검색결과 1,443건 처리시간 0.027초

Spatial Characteristics and Driving Forces of Cultivated Land Changes by Coupling Spatial Autocorrelation Model and Spatial-temporal Big Data

  • Hua, Wang;Yuxin, Zhu;Mengyu, Wang;Jiqiang, Niu;Xueye, Chen;Yang, Zhang
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제15권2호
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    • pp.767-785
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    • 2021
  • With the rapid development of information technology, it is now possible to analyze the spatial patterns of cultivated land and its evolution by combining GIS, geostatistical analysis models and spatiotemporal big data for the dynamic monitoring and management of cultivated land resources. The spatial pattern of cultivated land and its evolutionary patterns in Luoyang City, China from 2009 to 2019 were analyzed using spatial autocorrelation and spatial autoregressive models on the basis of GIS technology. It was found that: (1) the area of cultivated land in Luoyang decreased then increased between 2009 and 2019, with an overall increase of 0.43% in 2019 compared to 2009, with cultivated land being dominant in the overall landscape of Luoyang; (2) cultivated land holdings in Luoyang are highly spatially autocorrelated, with the 'high-high'-type area being concentrated in the border area directly north and northeast of Luoyang, while the 'low-low'-type area is concentrated in the south and in the municipal area of Luoyang, and being heavily influenced by topography and urbanization. The expansion determined during the study period mainly took place in the Luoyang City, with most of it being transferred from the 'high-low'-type area; (3) elevation, slope and industrial output values from analysis of the bivariate spatial autocorrelation and spatial autoregressive models of the drivers all had significant effects on the amount of cultivated land holdings, with elevation having a positive effect, and slope and industrial output having a negative effect.

간호사의 직장 내 괴롭힘 경험에 대한 융합적 접근 : 근거이론방법론 적용 (The Convergence Approach Based on Grounded Theory methodology on Nurse's Experience of Workplace Bullying)

  • 이윤주
    • 한국융합학회논문지
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    • 제9권12호
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    • pp.429-440
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    • 2018
  • 본 연구는 간호사의 직장 내 괴롭힘 경험과정을 탐색하고자 함이다. 2013년 4월 1일부터 2013년 7월 5일까지 직장 내 괴롭힘을 경험한 14명의 간호사를 대상으로 인터뷰하고 Strauss and Corbin의 근거이론방법론을 적용하여 분석하였다. 분석 결과, 간호사의 직장 내 괴롭힘은 139개의 개념, 35개의 하위범주, 13개의 범주로 구분되었다. 간호사가 경험하는 직장 내 괴롭힘의 중심현상은 '부정적으로 학습된 관성에 의한 존재의 무시'로 나타났고, 이를 해결하기 위한 핵심범주는 '자신을 되찾기 위한 몸부림'이었다. 본 연구는 괴롭힘을 경험하는 간호사의 역동과정을 제시함으로 개인과 조직의 직장 내 괴롭힘에 대한 인식의 변화에 긍정적으로 기여할 것이다. 추후 간호사의 직장 내 괴롭힘을 감소시키기 위한 직장 내 괴롭힘 현황 파악, 모니터링 방법 및 프로그램 개발에 대한 연구가 요구된다.

Performance of passive and active MTMDs in seismic response of Ahvaz cable-stayed bridge

  • Zahrai, Seyed Mehdi;Froozanfar, Mohammad
    • Smart Structures and Systems
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    • 제23권5호
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    • pp.449-466
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    • 2019
  • Cable-stayed bridges are attractive due to their beauty, reducing material consumption, less harm to the environment and so on, in comparison with other kinds of bridges. As a massive structure with long period and low damping (0.3 to 2%) under many dynamic loads, these bridges are susceptible to fatigue, serviceability disorder, damage or even collapse. Tuned Mass Damper (TMD) is a suitable controlling system to reduce the vibrations and prevent the threats in such bridges. In this paper, Multi Tuned Mass Damper (MTMD) system is added to the Ahvaz cable stayed Bridge in Iran, to reduce its seismic vibrations. First, the bridge is modeled in SAP2000 followed with result verification. Dead and live loads and the moving loads have been assigned to the bridge. Then the finite element model is developed in OpenSees, with the goal of running a nonlinear time-history analysis. Three far-field and three near-field earthquake records are imposed to the model after scaling to the PGA of 0.25 g, 0.4 g, 0.55 g and 0.7 g. Two MTMD systems, passive and active, with the number of TMDs from 1 to 8, are placed in specific points of the main span of bridge, adding a total mass ratio of 1 to 10% to the bridge. The parameters of the TMDs are optimized using Genetic Algorithm (GA). Also, the optimum force for active control is achieved by Fuzzy Logic Control (FLC). The results showed that the maximum displacement of the center of the bridge main span reduced 33% and 48% respectively by adding passive and active MTMD systems. The RMS of displacement reduced 37% and 47%, the velocity 36% and 42% and also the base shear in pylons, 27% and 47%, respectively by adding passive and active systems, in the best cases.

Experience of nursing students about the barriers to patient education: a qualitative study in Iran

  • Abbasi, Mohammad;Rabiei, Leili;Masoudi, Reza
    • Korean journal of medical education
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    • 제30권4호
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    • pp.327-337
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    • 2018
  • Purpose: Patient education is a dynamic and continuous process that should be implemented during the entire time of hospital stay and even afterward. Studies have shown the typically poor quality of patient education in Iran and its failure to convey the required knowledge and skills to patients. The purpose of this study was to survey the experience of nursing students in regard to the challenges of patient education in hospitals. Methods: This qualitative study was conducted using the conventional qualitative content analysis approach on a sample of 21 undergraduate nursing students (4th semester and beyond), which was drawn from the Qom Nursing and Midwifery School through purposive sampling with maximum variation. Data were collected through semi-structured interviews conducted over a period of 45 to 75 minutes, and were analyzed using the conventional qualitative content analysis. Results: Results were derived from the experiences of 21 nursing students (nine males, 12 females) about the research subject. The primary themes identified in the study were the student-related, patient-related, instructor-related, education environment-related, and curriculum-related barriers to patient educations. Conclusion: Participants believed that patient education in Iranian hospitals is faced with many challenges. Nursing instructors and curriculum planners should ensure more emphasis on patient education at the initial semesters of nursing education curriculum and make sure that it is included in the evaluation of students. Hospital officials should provide a dedicated education environment with suitable facilities, tools, and atmosphere for patient education. Also, special education programs need to be developed for less educated patients.

면진구조의 응답가속도 감소효과를 고려한 상부구조의 설계전단력 저감계수 (Design Shear Force Reduction Factor of Upper Structure in Seismic Base-isolated System Considering Response Acceleration Decrement Effect)

  • 천하오;오상훈
    • 대한건축학회논문집:구조계
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    • 제35권7호
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    • pp.165-170
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    • 2019
  • The structural damage caused by earthquake to the upper structure of seismic base-isolated system can be suppressed effectively because it is designed to concentrate the input energy on the seismic isolation floor. Further, the response acceleration of seismic base-isolated system can be greatly reduced compared to the seismic structure because of the long period, which means that the design shear force of the seismic base-isolated system can be reduced appropriately. However, when the design shear force is determined to be reduced, the design stiffness will decrease, and the response acceleration will increase oppositely. Therefore, for finding the extent to which the design shear force of the upper structure can be reduced, this paper considered the seismic base-isolated structure as the analytical model and proposed the design shear force reduction factor of the base-isolated structure through the dynamic response analysis, while considering the decrement effect of response acceleration. The research result shows that the response acceleration of the isolated the upper structure can be reduced by 50%~70% of the seismic structure under the same design conditions, and the design shear force can be reduced by up to 40%. By increasing the design stiffness over to 1.8 times of the original design value, the design shear force can be reduced to the same extent as the response acceleration can be reduced compared to the seismic structure.

하니문의 동학(動學)과 구조의 정학(靜學): 문재인 정부의 외교정책, 변화와 연속성 (Dynamics of Honeymoon and Statics of Structure: Changes and Continuity of Foreign Policy in the Moon Jae-In Administration)

  • 최진우
    • 의정연구
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    • 제24권2호
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    • pp.5-38
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    • 2018
  • 문재인 정부 출범 후 한반도 외교지형에는 지각변동이 진행되고 있다. 무엇보다도 교착 상태에 빠져 있던 북핵 문제 해결, 그리고 한반도의 적대 상태 종식을 향한 새로운 동력이 생성되고 있다. 이러한 거대한 변화가 진행되고 있는데는 '운전자론'으로 표현되는 문재인 정부의 창의적인 외교정책에 힘입은 바가 크다. 하지만 문재인 정부의 외교정책은 과거 보수정권의 외교정책과의 연속성 또한 보이고 있다. 문재인 정부는 한미동맹의 중요성을 지속적으로 강조하면서 북핵문제 등의 해결에 있어 미국과의 굳건한 공조체제를 유지할 것임을공개적으로 천명하고 있다는 점에서 특히 그러하다. 사실 외교정책의 연속성 유지는 국내적 합의 기반 구축, 대외적 신뢰 제고, 기대-현실 간극의 부작용 완화 등에 기여할 수 있다는 점에서 긍정적인 효과를 수반할 것으로 기대된다.

국내 OEM/ODM 화장품 제조기업의 생산계획 및 효율화를 위한 분산형 MRP시스템 개발 (Development of Distributed MRP System for Production Planning and Operation in Korean OEM/ODM Cosmetics Manufacturing Company)

  • 장동민;신문수
    • 산업경영시스템학회지
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    • 제43권4호
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    • pp.133-141
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    • 2020
  • Up to date cosmetic OEM/ODM (original equipment manufacturing/original development manufacturing) industry receives attention as a future growth engine due to steady growth. However, because of limited research and development capability, many companies have employed commercial management platforms specialized for large-sized companies; thus, overall system effectiveness and efficiency is low. Especially, MRP (material requirement planning) system introduced originally in 1970s is employed to calculate the requirement of the parts. However, dynamic nature of production lead time usually results in incorrect requirements. In addition, its algorithm does not consider the capability of the production resources. Also, because the commercial MRP system calculates all subcomponent for fixed period, the more goods have subcomponent, the slower calculation is. Therefore, conventional MRP system cannot respond complicated situation in time. In this study, we will suggest a new method that can respond to complicated situations resulting from short lead time and urgent production order in Korean cosmetic market. In particular, a distributed MRP system is proposed, that consists of multi-functional and operational modules, based on the characteristic of the BOM (bill of material). The distributed MRP system divides components (i.e. products and parts) into several fields and decrease the problem size; thus, we can respond to dynamically changed data any time. Through this solution, we can order components quickly, adjust schedules and planned quantity, and manage stocks reasonably. In addition, a prototype of the distributed MRP system is presented in this paper, in which ERP (enterprise resource planning) sever data is associated with an excel spreadsheet via MSsql. System user interface is implemented by a VBA (visual basic for applications) tool. According to a case study, response rate for delivery and planning achievement rate were enhanced about 20%, and inventory turnover was also decreased. Consequently, the proposed system improves overall profit.

Characterization of Phage Behaviors Against Antibiotic-Resistant Salmonella Typhimurium

  • Easwaran, Maheswaran;Ahn, Juhee
    • 한국식품위생안전성학회지
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    • 제35권6호
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    • pp.602-606
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    • 2020
  • 본 연구는 다양한 항생제 내성을 갖는 Salmonella enterica subsp. enterica serovar Typhimurium ATCC 19585 (STWT), S. Typhimurium KCCM 40253 (STKCCM), ciprofloxacininduced S. Typhimurium ATCC 19585 strains (STCIP), and S. Typhimurium CCARM 8009 (STCCARM)에 대한 phage의 흡착 및 용균 특성을 평가하였다. PBST-10, PBST-13, PBST-32, PBST-35, P-22, P-22 B1 phages는 narrow host range를 보였다. 숙주인 STWT, STKCCM, STCIP에 대한 phage의 흡착률은 각각 47-85%, 58-95%, 61-93%였지만, STCCARM에 대한 phage의 흡착률은 14-36%의 낮은 수준을 보였다. STWT, STKCCM, STCIP, STCCARM에 대한 phage burst size는 각각 43-350, 37-530, 66-500, 24-500 plaque-forming unit(PFU)으로 다양하게 관찰되었다. P-22 B1을 제외한 모든 phage는 배양 초기에 STCIP숙주를 효과적으로 저해하였다. 이러한 결과는 항생제 내성균을 저해하기 위해 phage control system 개발에 유용한 정보로 활용될 것이다.

비선형 규칙파 조건에서 기존 케이슨 방파제에 신규 케이슨 추가설치에 따른 케이슨들 간의 상호작용 영향 평가 (Interaction Effect between Caissons by Installation of New Caisson on Existing Caisson Breakwater in Second Order Stokes Wave Condition)

  • 박민수
    • 한국해안·해양공학회논문집
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    • 제33권6호
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    • pp.345-356
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    • 2021
  • 기존 케이슨 방파제의 구조적 안정성을 높이기 위해 신규 케이슨을 기존 케이슨 전면 또는 후면에 추가로 설치하여 보강하는 설계 및 시공사례가 발생되고 있다. 본 연구에서는 신규 케이슨이 추가로 설치되는 경우 입사하는 파랑과 구조물 간의 상호작용 영향에 따른 개별 케이슨에 작용하는 파력 특성을 분석하기 위해 상용프로그램인 ANSYS AQWA를 이용하여 수치해석을 수행하였다. 우선 주파수 영역에서 구조물에 작용하는 파력을 계산하여 개별 케이슨에 작용하는 파력 특성을 주기(주파수)별로 분석하였다. 그리고 특이한 파력분포 특성이 발생되는 주파수에 대해서는 시간영역 수치해석을 통해 개별 케이슨에 작용하는 동적파력 특성은 케이슨 간의 거리변화에 큰 영향을 받는 것을 확인하였다.

구조물-비구조요소 2자유도 결합시스템 해석을 통한 비구조요소 내진설계변수 평가 (Evaluation of Seismic Design Parameters for Nonstructural Components Based on Coupled Structure-Nonstructural 2-DOF System Analysis)

  • 배창준;이철호;전수찬
    • 한국지진공학회논문집
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    • 제26권3호
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    • pp.105-116
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    • 2022
  • Seismic demand on nonstructural components (NSCs) is highly dependent on the coupled behavior of a combined supporting structure-NSC system. Because of the inherent complexities of the problem, many of the affecting factors are inevitably neglected or simplified based on engineering judgments in current seismic design codes. However, a systematic analysis of the key affecting factors should establish reasonable seismic design provisions for NSCs. In this study, an idealized 2-DOF model simulating the coupled structure-NSC system was constructed to analyze the parameters that affect the response of NSCs comprehensively. The analyses were conducted to evaluate the effects of structure-NSC mass ratio, structure, and NSC nonlinearities on the peak component acceleration. Also, the appropriateness of component ductility factor (Rp) given by current codes was discussed based on the required ductility capacity of NSCs. It was observed that the responses of NSCs on the coupled system were significantly affected by the mass ratio, resulting in lower accelerations than the floor spectrum-based response, which neglected the interaction effects. Also, the component amplification factor (ap) in current provisions tended to underestimate the dynamic amplification of NSCs with a mass ratio of less than 15%. The nonlinearity of NSCs decreased the component responses. In some cases, the code-specified Rp caused nonlinear deformation far beyond the ductility capacity of NSCs, and a practically unacceptable level of ductility was required for short-period NSCs to achieve the assigned amount of response reduction.