• 문화기술의 융합
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• 제10권1호
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• pp.35-50
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• 2024

본 연구는 여대생의 월경전 증후군, 월경에 대한 태도, 수면의 질, 통증이 학습 몰입도에 미치는 영향을 파악하고자 시도되었다. 연구대상자는 경상남도 C 대학교 여대생 166명이며, 자료수집은 구글 설문지를 이용하여 2023년 7월 01부터 8월 31일까지 진행하였다. 수집된 자료는 상관관계, 다중회귀분석으로 분석하였다. 월경전 증후군은 월경에 대한 태도(r=.40, p<.001)와 월경통(r=.33, p<.001)과 유의한 정적 상관관계가 있었다. 그리고 수면의 질은 월경통(r=.31, p<.001), 학습몰입도(r=.24, p=.002)와 유의한 정적 상관관계가 있었다. 학습몰입도에 유의한 영향을 미치는 변인은 식사 '불규칙적'(β=.20, p=.007), 월경통 완화 '복무마사지'(β=.27, p=.003), 수면의 질(β=.16, p=.038)이었다. 월경통 완화 '복무마사지'가 학습몰입도를 가장 잘 예측하는 요인으로 나타났고, 그 다음 식사 '불규칙적', 수면의 질 순이었다. 총 설명력은 13.9%이었다. 이상의 결과를 토대로 월경전 증후군을 완화를 통한 학습몰입도 증가를 위해서는 다양한 치료법과 이에 대한 관심을 증대시켜 적극적인 대처 방안을 모색하고, 올바른 식사 습관을 갖추어 월경에 대한 긍정적인 태도를 갖도록 교육이 필요하다.

• International Journal of Control, Automation, and Systems
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• 제4권6호
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• pp.763-768
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• 2006

The two-for-one(TFO) twister is precision machinery that twists fibers rapidly under constant tension. Since the quality of the twisted yarn is directly deteriorated by faults of the twister, such as the distortion of the spinning axis, bearing abrasion, and tension irregularity, it is important to detect faults of the TFO twister at an early stage. In this research, a new algorithm is proposed to detect faults of the TFO twister and their causes, by measuring the vibrations of the TFO twister and obtaining frequency components with a FFT algorithm. The TFO twister with faults showed increased vibrations and each fault generated vibrations at different frequencies. By analyzing changes of characteristics of vibrations, we can determine faulty twisters. The proposed fault detection algorithm can be implemented cheaply with a signal processor chip. It can be used to find when to repair a faulty TFO twister without much loss of yam on-line.

• 한국주조공학회지
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• 제24권1호
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• pp.26-33
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• 2004

The pressure of the mold flux acting on the meniscus shell was investigated through the coupling analysis of heat transfer in the mold and fluid flow in the flux caused by the mold oscillation. Finite element method was employed to solve the conservation equation associated with appropriate boundary conditions. As reported by previous workers, the axial pressure is positive on the negative strip time and negative on the positive strip time. A maximum pressure is predicted toward the top of the meniscus shell which has the thin shell arid a maximum value is in proportion to the relative mold oscillation velocity. The relative mold oscillation velocity was changed by the effect of meniscus level fluctuation. Therefore the pressure of the mold flux acting on the meniscus shell was different each cycle of the mold oscillation due to the irregularity of relative mold oscillation velocity.

• Journal of Mechanical Science and Technology
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• 제20권9호
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• pp.1390-1398
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• 2006

A gerotor pump is suitable for oil hydraulics of machine tools, automotive engines, compressors, constructions and other various applications. In particular the pump is an essential machine element that feeds lubricant oil in an automotive engine. The subject of this paper is the theoretical analysis of internal lobe pump whose the main components are the two rotors. Usually the outer one is characterized by lobes with a circular shape, while the inner rotor profile is determined as a conjugate to the other. For this reason the first topic presented here is the definition of the geometry of the rotors starting from the design parameters. The choice of these parameters is subject to some limitations in order to limit the pressure angle between the rotors. Now we will consider the design optimization. The first step is the determination of the instantaneous flow rate as a function of the design parameter. This allows us to calculate three performance indexes commonly used for the study of positive displacement pumps the flow rate irregularity, the specific flow rate, and the specific slipping. These indexes are used to optimize the design of the pump and to obtain the sets of optimum design parameter Results obtained from the analysis enable the designer and manufacturer of the oil pump to be more efficient in this field.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.457-458
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• 2002

The fractal dimension is the characteristics that can quantitatively define the irregularity in natural. It is useful in describing the morphology or various rubbed surface for hydraulic piston motor instead of the stylus profiling method. But fractal parameters had not constructed on the morphological characteristic or rubbed surface because of the insufficient knowledge about a conception of fractal dimension. In this study, for the purpose or applying fractal I parameters practically, we have suggested way to establish the morphological characteristic of rubbed surface with fractal parameters, and we carried out an experiment on the lubricant friction and wear by using Ball-ON-Disk type tester. Materials were the brass and the bronze which are used to slipper-pad in the hydraulic piston motor. We searched for fractal parameters or surface structure with the digital image processing, Surface fractal dimension can be determined by sum of intensity difference of surface pixel. Using the image processing and fractal parameters for rubbed surface in the friction and wear test, morphology of rubbed sur race can be effectively obtained by fractal dimensions.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제12권1호
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• pp.202-209
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• 1990

A retrospective study of 498 patients (591 joints) who had diagnosed as having internal derangement of the temporomandibular joint by history, clinical examination, and arthrography were evaluated. 66 patients (70 joints) were diagnosed as having meniscus perforation between the joint compartments. In those patients with pain (11 joints : 15.7%), pain and crepitation (24 joints : 34.3%), pain, crepitation and LOM (31 joints : 44.3%), and painless crepitation with LOM (4 joints : 5.7%) complained clinically. All these patients who had perforation showed irregularity in outline of the contrast material, bone contour-contrast material gaps, flattening of cortical layer of articular eminence. On the 20 joints treated surgically, 17 joints were found to have meniscus perforation at the time of surgery which correlated with their pre-operative radiographic and clinical diagnosis. Three joints could not found perforation of meniscus. This study was designed to examine of the incidences of the meniscus perforation in the above patients and to assess the diagnostic accuracy of arthrography by comparing the results with the finding of direct examination at TMJ surgery.

• 폴리머
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• 제32권4호
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• pp.313-321
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• 2008

UV개시에 의해 광경화형 아크릴 공중합체를 합성하고 제조된 아크릴 점착제(PSA)의 박리 에너지와 물리적 특성을 조사하였다. 이때 acrylic acid(AA)의 함량을 변화시켜 점착제의 물성을 변화시켰으며, 피착제의 표면 거칠기, 표면 요철방향, 점착제의 두께를 변화시킴으로써 박리 에너지의 변화 추이를 조사하였다. 공단량체인 acrylic acid의 함량이 증가함에 따라 표면 거칠기가 낮은 피착제가 높은 박리 에너지를 보였으며 점착제의 두께가 두꺼워 질수록 증가하였다. 또한 피착제 표면의 요철방향이 박리방향과 수평일 때 특히 높은 박리 에너지를 갖는 것으로 나타났다. 이것은 점착제의 두께 감소와 피착제 표면 거칠기의 증가가 wetting의 감소를 초래하지만 박리 시 저항력은 오히려 증가하는 경향을 나타내기 때문일 것이라는 예상과도 잘 일치한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.303-310
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• 2011

This paper is focused on development of models for measuring lateral and vertical track irregularities from corresponding accelerometers of an in-service high-speed train. Generally, the track irregularity was measured by a special railway inspection vehicle or system with contact or non-contact sensors. However, the sensors are very expensive and vulnerable to a harsh environment. Displacement estimation from an inertial measurement unit and its wave-band filtering was already developed in the previous study, and it was found that their results included not only the track irregularities but also other information such as phase delay of the applied filters, and suspension and conicity of the wheel. To identify the track irregularities from those results, a compensation filtering method was proposed. Each directional compensation filter was derived by using a system identification method with the estimated directional displacement as input and the corresponding track irregularities as output. In this paper, they are integrated into a model for each direction and applied to the measured lateral and vertical acceleration data from the axle-box and bogie of an in-service high-speed train. Their results are compared with the data from the track geometry measurement system. From the comparison, the proposed models are a useful tool for the measurement of the track irregularities using accelerometers of in-service high-speed trains.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1115-1122
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• 2011

Reinforced-Roadbed materials are usually composed of crushed stones. Repeated load application can induce deformation in the reinforced-roadbed layer so that it causes irregularity of track. Thus it is important to develop a prediction model of elastic modulus based on stress-strain relation under repeatitive load in order to investigate behavior of reinforced roadbed. The prediction model of elastic modulus of the material can be obtained from repeated triaxial test. However, a proper size of the sample for the test must be used. In this study, a large repeatitive triaxial test apparatus with the sample size of diameter of 30 cm and height of 60cm was adapted for performing test of the crushed stone reinforced-roadbed considering large particle size to get resilient modulus Mr. The obtained resilient modulus was compared to shear modulus obtained from mid size resonant column test. The sample size effect is somewhat large enough so that it is required to design a scale factor based on similarity law in order to use smaller samples for getting elastic modulus of the crushed stone reinforced-roadbed material. A scale factor could be obtained from this study.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2049-2056
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• 2011

The reinforced-roadbed materials composed of crushed stones are used for preventing vertical deformation and reducing impact load caused by highspeed train. Repeated load application can induce deformation in the reinforced-roadbed layer so that it causes irregularity of track. Thus it is important to understand characteristics of permanent deformation in the reinforced-subbase materials. The characteristics of permanent deformation can be simulated by prediction model that can be obtained by performing repetitive triaxial test. The prediction model of permanent deformation is a key-role in construction of design method of track. The prediction model of permanent deformation is represented in usual as the hyperbolic function with increase of number of load repetition. The prediction model is sensitive to many factors including stress level etc. so that it is important to define parameters of the model as clearly as possible. Various data obtained from repetitive triaxial test and resonant column test using the reinforced-roadbed of crushed stone are utilized to develop a new prediction model based on concept of shear-stress ratio and elastic modulus. The new prediction model of permanent deformation can be adapted for developing design method of track in the future.