• Tribology and Lubricants
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• 제21권3호
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• pp.142-148
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• 2005

In order to improve the fuel economy by design change of automatic transmission, various technologies such as increased shift stages, slip control of lock-up clutch and compact and low-weight design have been developed. And also many OEMs have developed their own ATFs as a part of these automatic transmissions. In this study, to investigate the effects of ATF characteristics on fuel economy, we got the worldwide OEM ATFs and made some reference fluids. And physical properties, frictional characteristics and fuel economy using dynamometer test for these fluids were evaluated. From the investigation, it was found that viscosities of ATFs are correlated with fuel economy in dynamometer test and reducing the viscosities made it possible to obtain fuel economy.

• Clinical and Experimental Pediatrics
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• 제62권7호
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• pp.245-251
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• 2019

Hemodynamically significant preterm patent ductus arteriosus (PDA) affects mortality; comorbidities such as necrotizing enterocolitis, intraventricular hemorrhage, and bronchopulmonary dysplasia; and adverse long-term neurodevelopmental outcomes in preterm infants, particularly in very low birth weight infants. However, recent studies have indicated that there is no consensus on the causal relationship between PDA and neonatal outcomes, the benefit of PDA treatment, the factors guiding the need for treatment, and optimal treatment strategies. Such uncertainty has resulted in wide variations in practice for treating preterm PDA between units, regions, and nations. Nowadays, there has been a paradigm shift to more conservative treatment for preterm PDA, and suggestions regarding selective management of preterm PDA considering risk factors and hemodynamic significance are increasing. Neonatologist-performed echocardiography and advances in modalities to assess hemodynamic significance such as biologic markers and near-infrared spectroscopy also help improve the efficacy of selective treatment of preterm PDA.

• 한국임상약학회지
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• 제34권1호
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• pp.1-20
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• 2024

This review examines the pivotal clinical trials that evaluated the efficacy and safety of semaglutide, a glucagon-like peptide-1 (GLP-1) receptor agonist, in the management of obesity. The reported findings underscore significant and sustained weight loss achieved with semaglutide in diverse patient groups, although gastrointestinal disorders occurred frequently, leading to therapy discontinuation. Overall, the studies demonstrated the potential of semaglutide as a therapeutic option not only for type 2 diabetes but also for obesity. The treatment landscape in obesity is evolving, as reflected in changing regulatory approvals and clinical guidelines, suggesting a paradigm shift toward personalized approaches in this chronic disease states to achieve optimal treatment outcomes for patients.

• Journal of Biosystems Engineering
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• 제41권1호
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• pp.1-11
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• 2016

Purpose: The gear strength of a new mechanical transmission designed to increase the loading weight of small 4.8 kW tracked agricultural transporters was analyzed. Design improvements to increase the gear strength and reduce the gear weight were proposed after examining the parameters. Methods: Sixteen operators from three regions were surveyed to obtain the usage profile of small 4.8 kW transporters. Gear strength was evaluated by calculating contact stress and tooth root stress using commercial software following ISO 6336. Results: From the strength calculation for each gear pair, contact stress smaller than tooth root stresses were produced in all gear pairs. The safety factors in most cases exceeded 1.0, except in the case of gear pair II in group II. The design life of the transporter using gear pair II in group II was 42% under harsh conditions-thus, this design life needs improvement. A robust design was proposed by examining the relevant parameters (face width and profile shift coefficient) to increase the design life of the transporter. In addition, a lightweight design for gear pair I in group II that was considered overdesigned was proposed by examining the face width to reduce the weight of the drive gear by 42% and that of the driven gear by 30%. Conclusions: The Safety factor for the design life was examined through a gear strength analysis. After examining the relevant parameters, conditions for strength improvement were proposed to increase design life or adjust overdesigned gear. However, load conditions differ depending on the working conditions or user's preferences; therefore, it is necessary to conduct further studies in various regions.

• 한국정밀공학회지
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• 제24권10호
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• pp.137-145
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• 2007

The purpose of this study is developing a virtual bicycle system for improving the ability of postural balance control for adults in various age groups. The system consists of an exercise bicycle that allows tilt in accordance with the postural balance of the subject in the system, a visual display that shows virtual road, and a visual feedback system. The rider of the system tries to maintain balance on the bicycle with a visual feedback of a virtual road while the pedaling speed, the heading direction, and various weight distribution information are updated to the subject as visual feedbacks in the display. A series of experiments were performed with various subjects to find the factors related to postural balance control in the system. The related parameters obtained were weight shift, magnitude of the deviation from the center of the virtual road, and variables related to the movement of the center of pressure. The results found that the ability to control postural balance in the system improved with the presentation of visual feedback information of the distribution of weight. It was also found that the general performance of the subject on balance in the system improved after ten days long training. The results show that the newly developed system can be used for the diagnosis of postural balance as well as for the stimulation of various senses such as vision and somatic sense in the field of rehabilitation training.

• 한국의류학회지
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• 제22권7호
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• pp.826-832
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• 1998

In order to understand the influences of wearing clothings with different thermal insula-tions when men were exposed from $25^{\circ}C$ environment to 18$^{\circ}C$ environment, thermoregulatory responses were measured on 4 healthy female college students. Subjects rested wearing T-shirts, trousers, and socks called LC(total weight 541g) at 25$\pm$1$^{\circ}C$, 50$\pm$5% R.H. and then exposed to the room conditioned in 18$\pm$1$^{\circ}C$, 50$\pm$5$^{\circ}C$ R.H. with LC as it was(LC Type) or with T-shirts, trousers, socks, training wear upper garment, the training wear lower garment called HC (total weight 1368g)(HC Type) for 120 min. The results can be summarized as follows: 1) When subjects were exposed from $25^{\circ}C$ environment to 18$^{\circ}C$ environment, decrease of rectal temperature was significantly smaller in LC Type than in HC Type. 2)Increase of heat production and weight loss had no significant difference between two types of clothing. 3)Internal thermal conductance was higher in HC Type and external thermal conductance was higher in LC Type. Therefore total thermal conductance was higher in LC Type than in HC Type. 4)Decrease of skin temperature was greater in LC Type than in HC Type. 5)Subjects felt colder with LC Type than with HC Type, but did not feel differently in comfort sensation between two types of clothing. It was suggested that less decrease of rectal temperature in LC type inspite of more dry heat loss from body might be ascribed to a shift of blood from the shell area to the core area originating in the vasoconstriction and the lowered internal thermal conductance. In conclu-sion, the importance of the state of internal heat distribution in the homeostasis seemed to be reaffirmed.

• 한국양식학회지
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• 제3권1호
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• pp.39-48
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• 1990

인공사료의 단백질 함량이 옐로우$\cdot$퍼치(Percidae)의 성장에 미치는 영향을 조사하였다. 단백질 함량 50, 40 및 $27\%$의 정제된 사료를 20주간 투여한 결과 사육초기에는 $50\%$ 및 $40\%$ 단백질 사료 투여군이 $27\%$ 사료투여군 보다 성장이 빨랐으나 10주 이후부터는 성장이나 사료 전환효율이 거의 동일하였고 3개 실험군 간에 통계적으로 유의성이 있는 차이를 찾아 볼 수 없었다. 옐로우$\cdot$퍼치의 치어(체중 약 6g)는 사육개시후 약 10주 이후 혹은 체중이 약 12g에 달했을 때부터는 단백질 요구량이 철저하게 감소하는 경향을 나타내어 $27\%$ 단백질 사료로서 정상적인 성장을 보여 주었다. 이는 자연계에서 매우 강한 육식성으로 고단백 식성 어류인 퍼치를 일반상업용 사료($50-56\%$ 단백질)보다 약 $23\%$ 이상의 단백질이 절감된 $27\%$ 단백질 사료로 실내에서 사육할 수 있음을 의미한다.

• 인터넷정보학회논문지
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• 제11권4호
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• pp.59-72
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• 2010

WIM(Weigh-In-Motion) 시스템은 고속으로 이동 중인 차량의 무게를 측정하는 시스템이다. 기존의 WIM 시스템에서는 등속을 기준으로 차량의 무게를 측정하며 오차율이 10% 범위에 있다. 하지만 운전자의 가 감속 조작과 같은 비정상 주행패턴을 고려하고 있지 않으므로 실제 오차율은 더욱 크다. 이러한 오차를 최소화하기 위해서 비정상적인 주행패턴을 찾고 이를 적용한 개선된 WIM 시스템이 필요하다. 본 논문에서는 기존의 WIM 시스템의 오차율에 영향을 미치는 비정상 주행패턴을 분석하고 오차율을 최소화하는 개선된 WIM 시스템을 설계한다. 개선된 WIM 시스템은 기존의 시스템에 루프센서를 추가한 다단 루프 구조를 가진다. 또한 내부적으로 정의된 측정 함수를 개선하여 비정상 주행패턴별로 측정된 무게를 보정한다. 실험 분석 결과 개선된 WIM 시스템은 기존의 최대 평균 오차율 22.98% 에서 8% 미만으로 오차율이 감소한 사실을 알 수 있다.

• 대한인간공학회지
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• 제35권6호
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• pp.493-501
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• 2016

Objective: This study analyzes the effect of angle conditions of rehabilitation equipment used for supporting hemiplegic patients on their rehabilitation training for standing action. The study was performed by adjusting the rear angle of seat inclination through a motion analysis. Background: Owing to a loss of muscle rigidity and degradation of muscle control ability, hemiplegic stroke patients suffer from asymmetrical posture, abnormal body balance, and degraded balance abilities due to poor weight-shifting capacity. The ability to shift and maintain one's weight is extremely essential for mobility, which plays an important role in our daily life. Thus, to improve patients' ability to maintain weight evenly and move normally, they need to undergo orthostatic and ambulatory training. Method: Using a motion analysis system, knee movements on both hemiplegic side and non-hemiplegic side were measured and analyzed in five angles ($0^{\circ}$, $10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$) while supported by the sit-to-stand rehabilitation equipment. Results: The knee movements on both sides increased as the angle increased in angle support interval to support a hemiplegic patient's standing up position. In standing up interval, a hemiplegic patient's knee movement deviations on both sides decreased, and the movement differences between hemiplegic and non-hemiplegic legs also decreased as the angle increased. Conclusion: The results of this study showed that the rehabilitation effectiveness increases as the angle increases, leading to a balanced standing posture through the decrease of movement difference between hemiplegic and non-hemiplegic sides and an improved standing up ability through the increase of knee movement on both sides. However, angles higher than $50^{\circ}$ didn't provide a significant effect. Therefore, a support angle under $50^{\circ}$ was proposed in this study. Application: The results of this study are expected to be applicable to the design of sit-to-stand support equipment to improve the effectiveness of the rehabilitation process of hemiplegic patients.

• Wind and Structures
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• 제27권5호
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• pp.347-356
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• 2018

In this paper, stress distribution for a structurally stable greenhouse is considered in the present paper with subsequent investigation into the detailed stress distribution contour with the variation of self-weight and wind pressure level designation method under wind velocity of less than 30 m/sec. For reliable analysis, wind pressure coefficients of a single greenhouse unit were modeled and compared with experiment with correlation coefficient greater than 0.99. Wind load level was designated twofold: direct mapping of fluid dynamic analysis and conversion of modeled results into wind pressure coefficients ($C_P$). Finally, design criteria of EN1991-1-4 and NEN3859 were applied in terms of their wind pressure coefficients for comparison. $C_P$ of CFD result was low in the most of the modeled area but was high only in the first roof wind facing and the last lee facing areas. Besides, structural analysis results were similar in terms of stress distribution as per EN and direct mapping while NEN revealed higher level of stress for the last roof area. The maximum stress levels are arranged in decreasing order of mapping, EN, and NEN, generating 8% error observed between the EN and mapping results under 30 m/sec of wind velocity. On the other hand, effect of dead weight on the stress distribution was investigated via variation of high stress position with wind velocity, confirming shift of such position from the center to the forward head wind direction. The sensitivity of stress for wind velocity was less than 0.8% and negligible at wind velocity greater than 20 m/sec, thus eliminating self-weight effect.