• 제목/요약/키워드: Combination Approach

검색결과 1,355건 처리시간 0.028초

Longitudinal cracks in non-linear elastic beams exhibiting material inhomogeneity

  • Rizov, Victor I.
    • Structural Engineering and Mechanics
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    • 제71권2호
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    • pp.153-163
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    • 2019
  • Longitudinal fracture behavior of non-linear elastic beam configurations is studied in terms of the strain energy release rate. It is assumed that the beams exhibit continuous material inhomogeneity along the width as well as along the height of the crosssection. The Ramberg-Osgood stress-strain relation is used for describing the non-linear mechanical behavior of the inhomogeneous material. A solution to strain energy release rate is derived that holds for inhomogeneous beams of arbitrary cross-section under combination of axial force and bending moments. Besides, the solution may be applied at any law of continuous distribution of the modulus of elasticity in the beam cross-section. The longitudinal crack may be located arbitrary along the beam height. The solution is used to investigate a longitudinal crack in a beam configuration of rectangular cross-section under four-point bending. The crack is located symmetrically with respect to the beam mid-span. It is assumed that the modulus of elasticity varies continuously according a cosine law in the beam cross-section. The longitudinal fracture behavior of the inhomogeneous beam is studied also by applying the J-integral approach for verification of the non-linear solution to the strain energy release rate derived in the present paper. Effects of material inhomogeneity, crack location along the beam height and non-linear mechanical behavior of the material on the longitudinal fracture behavior are evaluated. Thus, the solution derived in the present paper can be used in engineering design of inhomogeneous non-linear elastic structural members to assess the influence of various material and geometrical parameters on longitudinal fracture.

Virtual Environment Building and Navigation of Mobile Robot using Command Fusion and Fuzzy Inference

  • Jin, Taeseok
    • 한국산업융합학회 논문집
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    • 제22권4호
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    • pp.427-433
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    • 2019
  • This paper propose a fuzzy inference model for map building and navigation for a mobile robot with an active camera, which is intelligently navigating to the goal location in unknown environments using sensor fusion, based on situational command using an active camera sensor. Active cameras provide a mobile robot with the capability to estimate and track feature images over a hallway field of view. In this paper, instead of using "physical sensor fusion" method which generates the trajectory of a robot based upon the environment model and sensory data. Command fusion method is used to govern the robot navigation. The navigation strategy is based on the combination of fuzzy rules tuned for both goal-approach and obstacle-avoidance. To identify the environments, a command fusion technique is introduced, where the sensory data of active camera sensor for navigation experiments are fused into the identification process. Navigation performance improves on that achieved using fuzzy inference alone and shows significant advantages over command fusion techniques. Experimental evidences are provided, demonstrating that the proposed method can be reliably used over a wide range of relative positions between the active camera and the feature images.

현지 식문화에 기반한 유럽권 김치 문화 확산 방안 연구 - 국내 체류 중인 유럽인을 대상으로 - (A Study of Method for Spreading Kimchi Culture in European Countries Based on Local Food Culture - Survey of European Residents in Korea -)

  • 권용민;고영주;이창현;박채린
    • 한국식생활문화학회지
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    • 제34권2호
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    • pp.184-200
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    • 2019
  • This study aims to establish a strategy for selling kimchi to satisfy the needs and wants of European consumers through survey, FGI, and IDI. All survey participants were Europeans and were selected on the basis of their kimchi awareness. For the quantitative survey, 246 participants 15 years or older were selected; for FGI, 33 participants aged between 20 and 49 were selected; and for IDI, eight chefs were selected. The survey included four steps of 'Awareness-First try-Needs-Future consumption'. The participants got to know kimchi through the Internet; for example, by visiting Korea and Hallyu, and suggested positive comments, including 'fancy' and 'exotic.' While satisfaction with kimchi sharply decreased due to taste and appearance in the first try of kimchi, it is important to provide the best first-try experience. It also showed that important needs for kimchi are 'hot sensation', 'crunchiness' and 'presentation'. They gave a negative answer to combination with traditional cuisines of their own country, but provided positive comments for benchmarking the use of traditional pickled foods. This study suggests that it may be necessary to implement a two-track strategy by the traditional kimchi as a 'strategic product' and localized kimchi as a 'key product'.

다문화가정 아동·청소년 자아개념의 구조모형: 생태체계모형을 기반으로 (A Structural Model of Self-Concept among Children and Adolescents from Multicultural Families Based on the Ecological Systems Model)

  • 오은진;성경미
    • 동서간호학연구지
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    • 제24권2호
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    • pp.171-181
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    • 2018
  • Purpose: The study aimed to validate a structural model of self-concept among children and adolescents from multicultural families. Methods: Data were collected from 325 mothers of multicultural families and their 417 children. Confirmatory factor analysis, path analysis and multiple mediation analysis with a phantom variable approach were used to assess construct validity and relations between model variables. Results: Goodness of fit indices of the modified theoretical model, the standardized ${\chi}^2$ (2.75), RMR (.02), RMSEA (.07), NFI (.90), TLI (.92), CFI (.94), GFI (.89), and AGFI (.87), met criteria. Social support and mental health problem had significant direct effects on self-concept, whereas residential environment and school adjustment had significant indirect effects, accounting in combination for 53% of the variance in self-concept. Conclusion: Based on the results, mental health problem mediated the relationships of self-concept and parenting stress.

소화성 궤양 출혈의 내시경 치료 (Endoscopic Hemostatic Treatment of Peptic Ulcer Bleeding)

  • 최연화;박준철
    • 대한상부위장관⦁헬리코박터학회지
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    • 제18권4호
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    • pp.235-241
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    • 2018
  • Peptic ulcer bleeding is a common complication of peptic ulcer disease and the most common cause of upper gastrointestinal bleeding. Despite advances in drug usage and endoscopic modalities, no significant improvement is observed in the mortality rate of bleeding ulcers. The purpose of this review is to discuss various endoscopic hemostatic methods to treat peptic ulcer bleeding. Endoscopic hemostatic techniques can be classified into injection, mechanical, electrocoagulation, hemostatic powder, and endoscopic Doppler-guided hemostatic therapies (the last mentioned being a newly developed technique). Endoscopic hemostasis can be performed as mono or combination therapy using the aforementioned methods. Endoscopic hemostasis is the most important treatment for patients with peptic ulcer bleeding. Endoscopists should consider the treatment approach for peptic ulcer bleeding based on patient characteristics, the size and shape of the lesion, the endoscopist's expertise, and the resources and circumstances at each hospital. Follow-up studies are needed to evaluate the efficacy of newly developed hemostatic powder therapy and endoscopic Doppler-guided hemostasis.

뇌성마비 아동의 엉덩관절에 관한 연구 (A Study for Hip Joint in Children with Cerebral Palsy)

  • 오태영
    • 신경치료
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    • 제22권3호
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    • pp.43-48
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    • 2018
  • Purpose The purpose of this study is to identify the prevalence, risk factors, characteristics, and interventions of hip joint problems in children with cerebral palsy, and to be able to serve as leverage for early detection, prevention, and function recovery. Method The electronic journal site was searched by the search terms "cerebral palsy", "hip joint", "hip joint dislocation", we analyzed and descript the cited articles from domestic and foreign papers in Pubmed 9, Science Direct 7, and K RISS analysis and analysis. Results Children with cerebral palsy showed the different prevalence according to their disability type, severity, and functional level, and we knew that abnormal neuromuscular control, stiffness, and biomechanical changes could be risk factors. Migration Index, Acetabolum Index, Neck shaft angle using by radiography and passive ROM test, special tests were available for the diagnosis and evaluation of the hip joint. Combination of physical therapy and orthopedic surgery was very important intervention, and complementary alternative therapy, orthosis, and postural assistant are effective. Conclusion We suggested that early detection and prevention is the most important periodic examination and that a multidisciplinary approach is a major factor in intervention.

Evolution of E. coli Phytase for Increased Thermostability Guided by Rational Parameters

  • Li, Jiadi;Li, Xinli;Gai, Yuanming;Sun, Yumei;Zhang, Dawei
    • Journal of Microbiology and Biotechnology
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    • 제29권3호
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    • pp.419-428
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    • 2019
  • Phytases are enzymes that can hydrolyze phytate and its salts into inositol and phosphoric acid, and have been utilized to increase the availability of nutrients in animal feed and mitigate environmental pollution. However, the enzymes' low thermostability has limited their application during the feed palletization process. In this study, a combination of B-value calculation and protein surface engineering was applied to rationally evolve the heat stability of Escherichia coli phytase. After systematic alignment and mining for homologs of the original phytase from the histidine acid phosphatase family, the two models 1DKL and 1DKQ were chosen and used to identify the B-values and spatial distribution of key amino acid residues. Consequently, thirteen potential amino acid mutation sites were obtained and categorized into six domains to construct mutant libraries. After five rounds of iterative mutation screening, the thermophilic phytase mutant P56214 was finally yielded. Compared with the wild-type, the residual enzyme activity of the mutant increased from 20% to 75% after incubation at $90^{\circ}C$ for 5 min. Compared with traditional methods, the rational engineering approach used in this study reduces the screening workload and provides a reference for future applications of phytases as green catalysts.

Shoot Induction and Genetic Stability of in vitro Cultured Pea

  • Kantayos, Vipada;Bae, Chang-Hyu
    • 한국자원식물학회:학술대회논문집
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    • 한국자원식물학회 2019년도 추계학술대회
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    • pp.30-30
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    • 2019
  • Pea (Pisum sativum) is one of important legume crops in the world. It is commonly used as a protein source for animal and human diet, and also used as a natural nitrogen source which is produced by a symbiotic bacterium in their root nodule and helpful for terrestrial ecosystem. The successful in vitro manipulation is depended on three main factors including physiology of plant donor, in vitro manipulation approach, and stress physiology during plant cultivation. Moreover, genotype is an important for plant manipulation; different genotype gives the different response to regeneration efficiency. An efficient condition of shoot induction for pea (Pisum sativum cv. 'Sparkle') was developed by using optimum explant, plant growth regulator concentrations, and pretreatment of BA onto explant. The average shoot number per explant showed the highest on two kinds of shoot induction media (MSB5 media containing 2 mg/L BA and a combination of 2 mg/L BA and 1 mg/L TDZ) with cotyledonary node explants culture. Moreover, the pretreatment of explant in 200 mg/L BA solution was found to be more effective in shoot induction than that of non-pretreatment. The analysis of genetic stability of regenerants by using 13 ISSR markers presented that in vitro regenerated plants showed polymorphism with 8.3% compared with their mother plants.

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Formulating A Competitive Advantage Model for Tourism Destinations in Indonesia

  • LESMANA, Henky;SUGIARTO, Sugiarto
    • The Journal of Asian Finance, Economics and Business
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    • 제8권3호
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    • pp.237-249
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    • 2021
  • Indonesia has successfully increased its ranking to 40th place in the 2019 Travel & Tourism Competitiveness Index. While tourism has become the country's second largest foreign exchange contributor, there is no existing competitive advantage model for Indonesian tourist destinations. The purpose and novelty of this study is to develop and formulate a competitive advantage model for Indonesia's tourism industry. The model will be based on the supply-side perception analysis of competitiveness indicators from Bali and five designated super-priority destinations in Indonesia. This model is expected to become a guideline for policymakers to design an effective and focused strategy. Data were obtained from in-depth interviews with, and questionnaires given to, 62 qualified industry players from the public and private sectors. This data-driven approach builds a relationship between competitiveness indicators and competitive advantages using a combination of importance-performance analysis and confirmatory factor analysis, thereby leveraging these advantages to generate a strategic model to compete in the international tourism industry. This would also be the first study to use this method in defining the competitive advantage of a destination. Using structural equation modeling, the study found that there are 54 indicators representing twelve dimensions of competitive advantages with good fit criteria.

경사못이 적용된 CLT-콘크리트 접합부의 하중전달능력 (Load Bearing Capacity of CLT - Concrete Connections with Inclined Screws)

  • 김경태;김종호
    • 대한건축학회논문집:구조계
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    • 제34권4호
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    • pp.3-13
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    • 2018
  • Load bearing capacity of dowel type fasteners loaded perpendicular to the shear plane is determined based on Johansen's yield theory (Johansen, 1949). In case of inclined screws whose axis is no longer perpendicular, the ultimate load of connection increases because of additional axial withdrawal capacity. To calculate load bearing capacity for inclined screws, KBC2016 and Eurocode5 provide design equations using the combination of two effects; axial and bending strength. Although their equations have been validated for a long time, there is still minimal information how to apply them for concrete-CLT joints. Since there are not many test data available, engineers have to make certain assumptions and thus results may look inconsistent in practice. In this paper, authors would like to describe the current approach and assumptions indicated by KBC2016 and Eurocode 5 and how they match the experimental results in terms of shear strength of CLT-concrete connections. To fulfill the objective, several push-out tests were performed on nine different test specimens. Each specimen has different penetration angles and depths. By analyzing load-displacement curves, the maximum shear strength, stiffness, and ductility were obtained. Shear strength values were compared with the current design codes and theoretical equations proposed in this paper. Observations on stiffness and ductility were briefly discussed.