• 한국해양공학회지
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• 제27권6호
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• pp.81-89
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• 2013

This paper considers the steering characteristics of a four-row tracked vehicle crawling on extremely cohesive soft soil, where each side is composed of two parallel tracks. The four-row tracked vehicle (FRTV) is assumed to be a rigid body with 6-DOF. A dynamic analysis program for the tracked vehicle is developed using the Newmark-${\beta}$ method based on an incremental-iterative scheme. A terra-mechanics model of an extremely cohesive soft soil is implemented in the form of the relationships of the normal pressure to the sinkage, the shear resistance to the shear displacement, and the dynamic sinkage to the shear displacement. In order to investigate the steering characteristics of the four-row tracked vehicle, a series of dynamic simulations is conducted with respect to the distance between the left and right tracks (pitch), steering ratios, driving velocity, reference track velocity, lengths of the tracks, and properties of the cohesive soft soil. Through these numerical simulations, the possibility of using a kinematic steering ratio is explored.

• PNF and Movement
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• 제13권2호
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• pp.73-80
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• 2015

Purpose: The purpose of this study was to determine the effect of symmetrical-reciprocal pattern of scapula and pelvis exercises using proprioceptive neuromuscular facilitation (PNF) on gait speed and balance in patients with hemiplegia. Methods: Among the adult patients with hemiplegia that were hospitalized at Michuhol Rehabilitation Center after being diagnosed with stroke, 10 that were capable of independent walking for more than five minutes and that understood and cooperated with the therapy and test methods of this research, were selected as subjects. The therapy was implemented based on the concept of PNF, and it was performed on a low mat and a height-adjustable mat, as proscribed by the fundamental procedure for PNF. Symmetrical-reciprocal pattern of scapula and pelvis exercises were applied to the patients in the decubitus position. The therapy scheme included stabilizing reversals, rhythmic stabilization, and a combination of isotonics, rhythmic initiation, and dynamic reversals. To investigate gait speed and body trunk mobility before and after the symmetrical-reciprocal pattern of scapula and pelvis exercises were applied, walking speed for a distance of 10 m was measured and balance was tested based on the Berg-Balance scale test table. The Berg-Balance scale test was performed by one therapist to minimize any error that could occur from the subjective evaluation method used by therapists. Results: Gait speed increased by 8.97 seconds after applying the symmetrical-reciprocal pattern of scapula and pelvis exercises using the concept of PNF, showing a significant difference (p<0.01). However, balance showed no significant difference after the therapy (p>0.14). Conclusion: Exercise therapy that uses the symmetrical-reciprocal pattern of scapula and pelvis with the concept of PNF can be said to be a useful therapeutic technique that can enhance the walking speed of patients with hemiplegia.

• Steel and Composite Structures
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• 제45권3호
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• pp.409-423
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• 2022

Nowadays, there is a high demand for great structural implementation and multifunctionality with excellent mechanical properties. The porous structures reinforced by graphene platelets (GPLs) having valuable properties, such as heat resistance, lightweight, and excellent energy absorption, have been considerably used in different engineering implementations. However, stiffness of porous structures reduces significantly, due to the internal cavities, by adding GPLs into porous medium, effective mechanical properties of the porous structure considerably enhance. This paper is relating to vibration analysis of fluidconveying cantilever porous graphene platelet reinforced (GPLR) pipe with fractional viscoelastic model resting on foundations. A dynamical model of cantilever porous GPLR pipes conveying fluid and resting on a foundation is proposed, and the vibration, natural frequencies and primary resonant of such a system are explored. The pipe body is considered to be composed of GPLR viscoelastic polymeric pipe with porosity in which Halpin-Tsai scheme in conjunction with the fractional viscoelastic model is used to govern the construction relation of nanocomposite pipe. Three different porosity distributions through the pipe thickness are introduced. The harmonic concentrated force is also applied to the pipe and the excitation frequency is close to the first natural frequency. The governing equation for transverse motions of the pipe is derived by the Hamilton principle and then discretized by the Galerkin procedure. In order to obtain the frequency-response equation, the differential equation is solved with the assumption of small displacement, damping coefficient, and excitation amplitude by the multiple scale method. A parametric sensitivity analysis is carried out to reveal the influence of different parameters, such as nanocomposite pipe properties, fluid velocity and nonlinear viscoelastic foundation coefficients, on the primary resonance and linear natural frequency. Results indicate that the GPLs weight fraction porosity coefficient, fractional derivative order and the retardation time have substantial influences on the dynamic response of the system.

• Parasites, Hosts and Diseases
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• 제61권2호
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• pp.202-209
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• 2023

Lophomonas blattarum is an anaerobic protozoan living in the intestine of cockroaches and house dust mites, with ultramicroscopic characteristics such as the presence of a parabasal body, axial filament, and absence of mitochondria. More than 200 cases of Lophomonas infection of the respiratory tract have been reported worldwide. However, the current diagnosis of such infection depends only on light microscopic morphological findings from respiratory secretions. In this study, we attempted to provide more robust evidence of protozoal infection in an immunocompromised patient with atypical pneumonia, positive for Lophomonas-like protozoal cell forms. A direct search of bronchoalveolar lavage fluid via polymerase chain reaction (PCR), transmission electron microscopy (TEM), and metagenomic next-generation sequencing did not prove the presence of protozoal infection. PCR results were not validated with sufficient rigor, while de novo assembly and taxonomic classification results did not confirm the presence of an unidentified pathogen. The TEM results implied that such protozoal forms in light microscopy are actually non-detached ciliated epithelial cells. After ruling out infectious causes, the patient's final diagnosis was drug-induced pneumonitis. These findings underscore the lack of validation in the previously utilized diagnostic methods, and more evidence in the presence of L. blattarum is required to further prove its pathogenicity.

• Steel and Composite Structures
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• 제50권2호
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• pp.201-216
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• 2024

This paper is motivated by the lack of studies relating to vibration and nonlinear resonance of fluid-conveying cantilever porous GPLR pipes with fractional viscoelastic model resting on nonlinear foundations. A dynamical model of cantilever porous Graphene Platelet Reinforced (GPLR) pipes conveying fluid and resting on nonlinear foundation is proposed, and the vibration, natural frequencies and primary resonant of such system are explored. The pipe body is considered to be composed of GPLR viscoelastic polymeric pipe with porosity in which Halpin-Tsai scheme in conjunction with fractional viscoelastic model is used to govern the construction relation of the nanocomposite pipe. Three different porosity distributions through the pipe thickness are introduced. The harmonic concentrated force is also applied on pipe and excitation frequency is close to the first natural frequency. The governing equation for transverse motion of the pipe is derived by the Hamilton principle and then discretized by the Galerkin procedure. In order to obtain the frequency-response equation, the differential equation is solved with the assumption of small displacement, damping coefficient, and excitation amplitude by the multiple scale method. A parametric sensitivity analysis is carried out to reveal the influence of different parameters, such as nanocomposite pipe properties, fluid velocity and nonlinear viscoelastic foundation coefficients, on the primary resonance and linear natural frequency. Results indicate that the GPLs weight fraction porosity coefficient, fractional derivative order and the retardation time have substantial influences on the dynamic response of the system.

• 헤리티지:역사와 과학
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• 제48권2호
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• pp.142-157
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• 2015

이 연구는 옹기장인들의 옹기제작기술을 전통지식이라는 관점에서 접근한 것으로 구체적인 옹기제작기술 속에 전통지식들이 어떻게 내재되어 있는지를 살핀 것이다. 특히 옹기제작 관련 전통지식들이 어떤 범주들로 구성되어 있으며 제작기술과의 관계에서 어떤 양상을 띠는가 하는 점들에 주목한다. 옹기제작 과정은 크게 재료의 준비, 기물의 성형, 소성 단계로 나누어지는데, 매 단계마다 고유한 전통지식들이 존재한다. 먼저 재료준비 단계에서는 각종 흙에 대한 지식들이 주를 이룬다. 흙의 색깔과 성질, 좋은 옹기흙의 지역 분포에 대한 정보, 옹기 제작에 적합한 것으로 흙을 재조정하는 기술 등이다. 그리고 두 번째의 기물 성형단계에서는 물레의 구조와 형태, 흙을 쌓아올리는 데 필요한 기술, 각종 도구를 사용하는 방법, 완성된 형태의 옹기를 건조하는 기술 등이 주를 이룬다. 마지막으로 소성 단계에서는 가마에 대한 지식과 가마 제작 기술, 가마 내 옹기를 쟁이는 기술, 화목에 대한 지식과 불 때는 기술, 불의 종류 등이 주를 이룬다. 이들 지식들은 각각 별개로 존재하지 않고 상호 밀접한 관련을 맺고 있다. 이는 어느 한 과정이 잘못되어도 완전한 옹기의 생산이 어려워지기 때문이다. 지식의 내용을 중심으로 볼 때 이들은 재질 색상 형태 분포양상 용융점 강도 물리적 성질 등과 같은 과학적 범주에 속하는 것들이 많다. 하지만 이들 지식들은 공식적 제도교육과정을 통해 얻은 것들이라기보다는 비공식적인 도제교육을 통한 오랜 경험속에서 터득한 것들이 대부분이다. 그리고 지식의 체계는 쉽게 드러나지 않는데, 주로 민속과학(ethnoscience)적 분류와 범주 속에서 이해될 수 있는 것들이 대부분이다. 이들 지식들은 유네스코 세계무형문화유산의 개념으로 보면 '자연 및 우주에 관한 지식'범주에 속한다. 이와는 달리 신체와 사용 도구, 그리고 제작하고자 하는 기물을 일체화시켜 내는 것으로 '신체기술(body techniques)'이라 부를 수 있는 것들도 있다. 이에 대해서는 옹기장인들 스스로도 설명하는 데 어려움을 가지며, 그들이 굳이 설명을 하더라도 해당분야에 대한 경험과 식견이 없는 한 이해가 쉽지 않다. 이러한 지식들은 습득 및 전승방식에 따라 구분해보면,'옹기 장인의 일반적 지식'과 '특정 옹기 장인만이 갖춘 고유한 지식'들로 구분할 수 있다. 그리고 지식이 갖는 축적된 시간의 깊이에 따라 '역사가 긴 지식'과 '최근에 만들어진 지식'등이 있을 수 있다. 옹기제작과정에서 드러난 옹기 장인들의 기술과 전통지식은 재료의 준비과정에서부터 최종 완성품이 만들어지기까지의 전 과정에서 수많은 범주와 층위의 기술들이 긴밀하게 연계되어 있다. 이러한 양상은 '기술의 사슬(techniques chain)'이라고 할 만하다. 이때의 기술은 반드시 자연과학적 범주의 기술(techniques)만을 의미하는 것은 아니며, 솜씨(skill)를 비롯하여 장인들 스스로도 의식하기 어려운 습관적 행위들까지를 포함하는 다양한 층위의 기술과 지식들이라고 할 수 있다.

• 한국농공학회지
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• 제28권3호
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• pp.79-88
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• 1986

Drought occurs most frequently and severely around transplanting season of the rice plants in Korea. Shortage of water due to drought for the paddy fields often delays transplanting, and less often the rice plants are subjected to water stress after delayed transplanting. The present study aimed at quantification of the rice crop loss due to delayed transplanting, different inten3ity of water stress, and the combined effect of delay in transplanting followed by water stress for better use of limited water for irrigation under drought. The rice variety Chucheong, a japonica, and Nampung, an indica x japonica, were grown, transplanted to 1/200 a plastic pots, and subjected to different timing of transplanting and degree of water stress under a rainfall autosersing, sliding clear plastic roof facility with completely randomized arrangement of 5 replications. The results obtained are summarized as follows: 1.Twelve days or 22 days delay in transplanting without water stress reduced rice yield by 25% and 43% in the japonica variety, and by 15% and 60% in the indica x japonica variety. 2.The 10 days or 20 days water stress developed without irrigation after drainage in the rice plants transplanted at proper time lowered the water potential at the paddy soil 10cm deep to -4 bar, and -12 bar and caused rice yield reduction by 14%, and 45% in the japonica variety and by 8%, and 50% in the indica X japonica variety. 3.The 12 days delay in transplanting and 10 days or 20 days water stress reduced rice yield by 39% and 59% in the japonica variety, and by 38% and 52% in the indica x japonica variety. The 22 days delay in transplanting plus 10 days water stress caused yield reduction by 76%, i.e. meaningless yield, in both varieties. 4.The intermittent irrigation just to wet the soil body for 10 days after 10 days water stress without irrigation increased rece yield by 12 to 16% compared to the rice plants water stessed without irrigation continuously for 20 days in both varieties respectively. 5.The above results suggest strongly 1) to transplant the rice plants at proper .time even with some water stress rather than delay for sufficient water from later rainfall, and 2) to distribute insufficient irrigation water to broader area of transplanted rice with limited irrigation for better use of limited irrigation water. A greater sensitivity of japonica variety to a moderate water stress than the indica X japonica variety during initial rooting and tillering stage was noticed. To cope with frequent drought in rice culture, firstly the lasting time of transplanting without yield reduction should be clarified by region and variety, and secondly a scheme of rational distribution of limited water should be developed by region with better knowledge on the varietal distribution of limited water should be developed by region with better knowledge on the varietal responses to varying intensity of water stress.

• 한국과학교육학회지
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• 제37권6호
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• pp.1037-1049
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• 2017

본 연구의 목적은 배설에 대한 소집단 모델링 기반 탐구 활동에서 나타나는 중학생들의 대화적 논변활동 과정에서 담화 이동 흐름과 합의에 이르는 추론 과정을 심층적으로 탐색하는 것이다. 참여 학생들은 영재원 중학교 학생들 17명이며, 3~4명이 한 소집단을 이루었다. 배설에 대한 소집단 모델링 활동 중에서 치킨을 먹은 후 체내에서 생성되는 노폐물(암모니아)는 우리 몸에서 어떻게 될지 설명하는 초기 모델을 형성하는 활동을 대상으로 분석이 이루어졌다. 학생들의 모델링 활동 중 논변적 상호작용을 분석한 결과 다음과 같은 결과를 확인할 수 있었다. 우선, 최초의 주장이 나타나는 잠정적 합의하기, '질문하기'와 '의미 명확히 하기'가 나타나는 불확실성 해결하기와 같은 공통적인 논변활동 단계가 나타났고, 다양한 주장이 존재한 소집단에서는 합의하기 단계가 추가적으로 나타나 '주장변경하기'의 담화 이동이 나타났다. 합의에 도달하기 위해 협력적으로 다른 사람의 논변에 참여했다는 측면에서 대화적 논변활동이 나타난 것을 확인할 수 있었다. 또한, 학생들의 논변활동에서 불확실성 해결하기 단계에서 비판적 질문을 하는 과정과 합의하기 단계에서 주장을 정당화하는 추론 과정에서 소집단 합의가 일어나도록 하는 대화적 논변활동 과정을 확인할 수 있었다. 비판적 질문을 통해 기존의 주장이 강화되거나 탈락되어 학생들은 자신의 주장을 변경하거나 새로운 주장을 제시하기도 하였다. 소집단 합의가 나타나는 순간의 추론을 분석해보면, 학생들은 개인 경험에 근거한 추론을 위한 자료 출처보다 과학적 사실에 근거한 추론을 위한 자료 출처를 선호하였으며 다양한 논변의 정당화 분석틀로 정당화를 하여 소집단 주장을 공고히 하였다. 본 연구결과를 통해 과학 수업에서 대화적 논변활동 맥락을 이해하고 반영할 수 있는 교육적 함의를 제공해줄 수 있을 것이다.

• 사상체질의학회지
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• 제23권1호
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• pp.63-78
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• 2011

1. Objectives: We aimed to propose a sub-classification system for the Taeeumin symptomatology by examining the Taeeumin pathology and symptomatology descriptions appearing in "Donguisusebowon". 2. Methods: The Gabo Edition and the Sinchuk Edition (the upgraded and revised edition) of "Donguisusebowon" were reviewed and examined for relevant information on the Taeeum pathology and symptomatology. 3. Results and Conclusions: 1) In the Taeeumin symptomatology, the Exterior disease develops from the basic pathology of Esophagus-Cold and the Interior disease from that of Liver-Heat, eventually progressing to damage of the expirational and dispersive energy of the Lung Sector, the Prime Core Organ or the excessively small organ of the Taeeum constitutional type. The resulting pathology can be broadly defined as the "Lung-Dryness symptomatology". 2) The case reports introduced in the Exterior disease section, including the Zhang Zhongjing Mahuang-tang treatment, Prolonged-affliction disease treatment, and Exterior disease Pestilential disease treatment, share several points in common. They all arise from the pathology of "weakness in the Lung sector and deficiency in the Exterior sector", and they can all be assigned to the same symptomatological division that presents with systemic heat and cold intolerance; this symptomatology can be defined as the "Esophagus-Cold symptomatology", the milder subdivision of the exterior symptomatology. 3) The body of text appearing in the last part of the Interior disease section commonly referred to as the "Taeeumin Conspectus" is in fact not a conspectus when its contents are actually examined. Instead, it can be understood from its pathological and symptomatological descriptions that the passage is explaining the more severe subdivision of the exterior symptomatology that has progressed from Esophagus-Cold to a pathology characterized by damaged expirational and dipersive energy of the Lung Sector. 4) The relocation of the "dry-related pathology" indicates a change in perspective regarding the "Dry-related symptomatology", which caused the rearrangement of the Interior disease into divisions of Liver-Heat symptomatology that is characterized by fulminant heat pathology and Dry-Heat symptomatology that is also accompanied by Lung-Dryness. 5) The Interior disease Yin-Blood Consumptive symptomatology should be included in the Dry-Heat symptomatology in the pathological scheme. 6) Based on the above, the subdivisions of the Taeeumin symptomatology should be arranged as "Esophagus-Cold symptomatology" and "Lung-Dry-Cold symptomatology" in the Exterior disease and "Liver-Heat symptomatology" and "Dry-Heat symptomatology" in the Interior disease.

• 대한지리학회지
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• 제39권5호
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• pp.735-754
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• 2004

이 논문은 정치생태학이론을 정치적 및 경제적 불균등 간의 연계측면과 환경파괴에 초점을 맞춘 측면을 동시에 개략적으로 검토한 것이다. 본 논문에서는 정치생태학 전통을 '고전적', '민주적', '탈 구조주의적'으로 나누는 3가지 분류 도식을 채택하였다. 탈 구조주의 전통은 협의의 준(準)이상적인 담론으로부터 존재론적이고 인식론적인 이슈에 더 강한 철학적 참여로 나아갈 필요가 있다. 후자의 견해는 니체의 유물론에서 발전된 Gilles Deleuze의 것에 입각한다. 이러한 배경에서. 본 논문은 1970 및 80년대에 북미의 환경운동으로부터 발달된 비교적 새로운 지적 전통인 '생물지역주의'에 관한 문헌들을 검토한다. 또한 이른바 '생물지역적 접근'은 행정단위는 생태-지리적 및 문화적 현상을 갈라놓기보다는 반영할 필요가 있다. 생물지역주의는 탈 구조주의적 정치생태학의 수정 필요성에 동조하는 지리학자와 계획가들에게 잠재적인 실용적 연구의 개념적 틀로서 평가된다. 결론적으로 정치생태학에 대한 생물지역적 접근은 비평에 의해 확인된 약점들을 회피하면서. 기초적인 철학적 관념의 고려사항의 범위론 제공하고. 그로부터 탈 구조주의적 정치생태학의 실용적 발달을 이룰 수 있다.