• 대한인간공학회지
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• 제34권3호
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• pp.279-291
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• 2015

Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods. Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient. Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels. Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg ($r^2=0.97$) and 15.3kg ($r^2=0.97$) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg. Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

• 방송공학회논문지
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• 제16권6호
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• pp.902-915
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• 2011

영역기반 스테레오 매칭 분야에서 최근 인간의 시각체계(Human Visual System)에 기반하여 영역내의 밝기값과 거리값에 따라 적응적으로 가중치를 부여하는 적응적 영역 가중치(Adaptive Support-Weight, ASW) 방법이 좋은 매칭 결과를 보이고 있다. 그러나 이 방법은 좋은 매칭 결과에 비해서 많은 연산비용을 필요로 하게 되고, 매칭의 실시간 시스템화에 큰 장애요소로 작용한다. 이에 Bilateral filter 수식으로 근사화 후 Integral Histogram 기법을 적용하여 영역 윈도우의 크기에 상관없이 상수 시간 O(1) 내에 매칭을 수행하는 연구가 진행되었다. 하지만 이 방법은 근사화 과정에서의 원 ASW 수식을 왜곡하기 때문에 매칭 정확도의 손실을 가져오게 된다. 본 논문에서는 적응적 영역 가중치 알고리즘의 매칭 정확도를 유지하면서 적응적 영역 가중치 알고리즘의 계산 비용을 줄이는 알고리즘을 제안한다. 이를 위해 영역내의 픽셀을 그룹화하여 근사화된 매칭을 수행하는 Sub-Block 방법과 영상의 에지 정보에 따라 적응적으로 시차 탐색 범위를 조정하는 방법을 제안한다. 결과적으로 제안된 기법은 기존 방식보다 좋은 매칭 정확도를 유지하면서도 효율적으로 계산 수행 시간을 줄이게 된다.

• 한국정보통신학회논문지
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• 제15권4호
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• pp.877-885
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• 2011

협업 필터링은 추천시스템들 중에서 가장 널리 사용되는 기법이다. 그러나 협업 필터링은 추천의 정확성을 떨어뜨리는 희소성과 확장성 문제를 가지고 있으며 이를 해결하기 위한 다양한 연구가 이루어지고 있다. 본 논문에서는 협업필터링의 희소성과 확장성의 문제를 해결하기 위해 가중치를 사용한 기법을 제안한다. 제안한 기법은 데이터 셋에서 추천의 정확성을 높이기 위해 평가값이 4이상인 데이터들만을 사용하여 아이템을 선호하는 사용자 정보를 분석한다. 아이템의 장르 정보와 분석한 사용자 정보를 유사도 계산 시 가중치로 사용하고 임계값 이상의 유사도를 가진 데이터들만으로 예측값을 계산하여 평가되지 않은 데이터의 평가값으로 사용한다. 제안한 기법은 아이템에 대한 특성을 분석하여 예측값을 계산함으로써 희소성을 줄임과 동시에 정확성을 더 높일 수 있고 새로운 아이템과 사용자가 등록되었을 때 분석된 정보를 바탕으로 빠른 분류가 가능하다. 실험을 통해 제안한 기법이 기존의 아이템 기반, 장르 기반 기법보다 추천의 정확성이 향상되는 것을 확인하였다.

• Architectural research
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• 제15권4호
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• pp.207-214
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• 2013

A form-finding technique is proposed for three-dimensional spatial structures. Two-step discrete finite element (FE) mesh generator based on computer aided geometric design (CAGD) is introduced and used to control the shape of three-dimensional spatial structures. Mathematical programming technique is adopted to search new forms (or shapes) of spatial structures. For this purpose, the strain energy is introduced as the objective function to be minimized and the initial volume (or the initial weight) is considered as constraint function. Numerical examples are carried out to test the capability of the proposed form-finding techniques and provided as benchmark tests.

• Neonatal Medicine
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• 제28권3호
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• pp.108-115
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• 2021

Purpose: Magnetic resonance imaging (MRI) is a useful tool for evaluating brain injury and maturation in preterm infants and often requires sedation to acquire images of sufficient quality. Infant sedation is often associated with adverse events, despite extreme precautions. In this study, the swaddling technique was investigated as an alternative non-pharmacological strategy to obtain brain MRIs of sufficient quality. Methods: We applied the feed and swaddle technique during routine brain MRI as a quality improvement project and compared its morbidity with that of sedation in a historic age-matched group. Seventy-nine very low birth weight infants in the neonatal intensive care unit of Ajou University Hospital (Suwon, Korea) were enrolled. Thirty-two (40.5%) infants were in the feed and swaddling group, and 47 (59.5%) were in the sedation group. Results: The morbidity associated with the cardiopulmonary system (swaddling group vs. sedation group: 53.13% [n=17] vs. 63.83% [n=30], P=0.723) and central nervous system (40.63% [n=13] vs. 29.79% [n=14], P=0.217) were not significantly different between groups. The MRI failure rate was not significantly different (swaddling group vs. sedation group: 12.5% [n=4] vs. 4.3% [n=2], P=0.174). The MRI scanning time was longer in the swaddling group than in the sedation group (76.5±20.3 minutes vs. 61.5±13.6 minutes, P=0.001). Cardiopulmonary adverse events were significantly less common in the swaddling group than in the sedation group (3.13% [n=1] vs. 34.04% [n=16], P=0.002). Conclusion: The success rate of MRI was comparable between the swaddling technique and sedation. Furthermore, despite the drawback of prolonged scan time, cardiopulmonary adverse events are fewer with swaddling than with sedative agents. Therefore, swaddling can be an alternative to sedation or anesthesia when performing neonatal MRI scans.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2973-2978
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• 2011

In this paper, a system is developed to support multi-attribute decision making for designing light-weight of rolling stock. Conceptual design of light-weight of rolling stock does not only mean reducing weight. It should be considered about some attributes like safety and environment, technology, etc. So technical attributes and needs of customers, manufacturers and management companies, passengers, should be reflected and qualitative evaluation methods are required. AHP(Analytical Hierarchy Process) and QFD(Quality Function Deployment) are used to decide weighted values of technical attributes and needs from customers. Finally, Alternatives for light-weight of rolling stock that are composed of alternatives of equipment are evaluated by TOPSIS(Technique for Order Preference by Similarity to Ideal Solution). A series of this process are made as a S/W. It could suggest a near-optimal alternative for light-weight of rolling stock.

• 한국자동차공학회논문집
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• 제16권1호
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• pp.175-180
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• 2008

Due to the global environment problems and the consumer's need for higher vehicle performance, it becomes very important for the global car makers to reduce vehicle weight. To reduce vehicle weight, many car makers have tried to use lightweight materials, for example, aluminum, magnesium, and plastics, for the vehicle structures and components. Especially, the ASF(aluminum space frame) is known for the excellent concept of the vehicle to satisfy structural rigidity, safety performance and weight reduction. In this research, the design of experiments and the multi-disciplinary optimization technique were utilized to meet the weight and structural rigidity target of the ASF. For the structural performance of the ASF, the locations and the size of aluminum extruded frames, aluminum cast nodes, and the aluminum sheets were optimized. As a result, the optimization design procedure has been set up to meet both structural and weight target of the ASF, and the assembled ASF showed good structural performance and weight reduction.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집A
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• pp.165-170
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• 2000

The weight function method is an efficient technique to calculate the stress intensity factors for various loading conditions in that only the stress analysis of an uncracked model is required. This paper analyzes the mixed-mode stress intensity factors of surface and deepest points for quarter elliptical surface cracks in mechanical joints by weight function method and the coefficients included in weight function are determined by finite element analyses for reference loadings. Results for the different number of terms in weight function are presented.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.155-163
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• 2006

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code(ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool(CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame. Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.

• Archives of Plastic Surgery
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• 제45권3호
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• pp.222-228
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• 2018

Background The most common surgical treatment for paralytic lagophthalmos is the placement of a weight implant in the upper eyelid; however, this technique confers the risks of implant visibility, implant extrusion, and entropion. In this study, we present a new technique of placing platinum weight implants between the levator aponeurosis and inner septum to decrease such complications. Methods A total of 37 patients with paralytic lagophthalmos were treated between March 2014 and January 2017 with platinum weight placement (mean follow-up, 520.1 days). After dissecting through the orbicularis oculi muscle, the tarsal plate and levator aponeurosis were exposed. The platinum weights (1.0-1.4 g) were fixed to the upper margin of the tarsal plate and placed underneath the orbital septum. Results Five patients could partially close their eye after surgery. The average distance between the upper eyelid and the lower eyelid when the eyes were closed was 1.12 mm. The rest of the patients were able to close their eye completely. Three patients patient developed allergic conjunctivitis after platinum weight insertion, which was managed with medication. None of the patients complained of discomfort in the upper eyelid after surgery. Visibility or extrusion of the implant were observed in three patients. Conclusions Postseptal weight placement is a safe and reproducible method in both primary and secondary upper eyelid surgery for patients with paralytic lagophthalmos. It is a feasible method for preventing implant visibility, implant exposure, and entropion. Moreover, platinum is a better implant material than gold because of its smaller size and greater thinness.