• Asian-Australasian Journal of Animal Sciences
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• 제31권11호
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• pp.1700-1713
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• 2018

Objective: The aim of this study was to verify the usefulness of artificial neural networks (ANN), multivariate adaptive regression splines (MARS), naïve Bayes classifier (NBC), general discriminant analysis (GDA), and logistic regression (LR) for dystocia detection in Polish Holstein-Friesian Black-and-White heifers and cows and to indicate the most influential predictors of calving difficulty. Methods: A total of 1,342 and 1,699 calving records including six categorical and four continuous predictors were used. Calving category (difficult vs easy or difficult, moderate and easy) was the dependent variable. Results: The maximum sensitivity, specificity and accuracy achieved for heifers on the independent test set were 0.855 (for ANN), 0.969 (for NBC), and 0.813 (for GDA), respectively, whereas the values for cows were 0.600 (for ANN), 1.000 and 0.965 (for NBC, GDA, and LR), respectively. With the three categories of calving difficulty, the maximum overall accuracy for heifers and cows was 0.589 (for MARS) and 0.649 (for ANN), respectively. The most influential predictors for heifers were an average calving difficulty score for the dam's sire, calving age and the mean yield of the farm, where the heifer was kept, whereas for cows, these additionally included: calf sex, the difficulty of the preceding calving, and the mean daily milk yield for the preceding lactation. Conclusion: The potential application of the investigated models in dairy cattle farming requires, however, their further improvement in order to reduce the rate of dystocia misdiagnosis and to increase detection reliability.

• 한국정보과학회논문지:소프트웨어및응용
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• 제31권4호
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• pp.387-393
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• 2004

DNA 컴퓨팅은 생체 분자들의 막대한 병렬성을 정보 처리 기술에 적용한 기술로, Np-complete문제를 해결하기 위하여 사용되고 있다. 하지만 DNA 컴퓨팅 기술만으로 NP-complete 문제를 해결할 경우에는 해를 찾지 못하거나 많은 시간이 걸리는 문제점이 있다. 본 논문에서는 DNA 코딩 방법을 적용하여 DNA 서열을 효율적으로 표현하고, 반응횟수 만큼 합성과 분리 과정을 거쳐 코드를 생성하는 ACO(Algorithm for Code Optimization)를 제안했다. 그리고 ACO를 NP-complete 문제 중의 하나인 Hamiltonian Path Problem에 적용하였다. 그 결과 ACO는 Adleman의 DNA 컴퓨팅 알고리즘 보다 가변길이의 DNA 코드를 효율적으로 표현할 수 있다는 것을 확인하였다. 또 한 ACO는 Adleman의 DNA 컴퓨팅 알고리즘 보다 탐색 시간과 생물학적 오류율을 50%정도 줄일 수 있었으며, 빠른 시간 내에 정확한 경로를 탐색할 수 있었다.

• Tribology and Lubricants
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• 제35권4호
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• pp.222-228
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• 2019

As rubber products such as O-rings, which are also known as packings or toric joints, come in regular, long term contact with liquid fuel, they can eventually swell, become mechanically weakened, and occasionally crack; this diminishes both their usefulness and intrinsic lifetime and could cause leaks during the steady-state flow condition of the fuel. In this study, we evaluate the lifetime of such products through compression set tests of FKM, a family of fluorocarbon elastomer materials defined by the ASTM international standard D141; these materials have great compression, sunlight, and ozone resistance as well as a low gas absorption rate. In this process, O-rings are immersed in the liquid fuel of airtight containers that can be expressed as a compression set, and the liquid fuel leakage in a flow rig tester at variable temperatures over 12 months is investigated. Using the Power Law model, our study determined a theoretical O-ring lifetime of 2,647 years, i.e. a semi-permanent lifespan, by confirming the absence of liquid fuel leakage around the O-ring assembled fittings. These results indicate that the FKM O-rings are significantly compatible for fuel tests to evaluate long-term sealing conditions.

• 대한의용생체공학회:의공학회지
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• 제32권1호
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• pp.7-14
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• 2011

This study suggested an optimized algorithm for detecting the loss of balance(LOB) in the seated position. And the sensitivity analysis was performed in order to identify the role of each design variable in the algorithm. The LOB algorithm consisted of data processing of measured signals, an internal model of the central nervous system and a control error anomaly(CEA) detector. This study optimized design variables of a CEA detector to obtain improved values of the success rate(SR) of detecting the LOB and the margin time(MT) provided for preventing the falling. Nine healthy adult volunteers were involved in the experiments. All the subjects were asked to balance their body in a predescribed seated posture with the rear legs of a four-legged wooden chair. The ground reaction force from the right leg was measured from the force plate while the accelerations of the chair and the head were measured from a couple of piezoelectric accelerometers. The measured data were processed to predict the LOB using a detection algorithm. Variables S2, h2 and hd are related to the detector: S2 represents a data selecting window, h2 a time shift and hd an operating period of the LOB detection algorithm. S2 was varied from 0.1 to 10 sec with an increment of 0.1 sec, and both h2 and hd were varied from 0.01 to 1.0 sec with an increment of 0.01 sec. It was found that the SR and MT were increased by up to 9.7% and 0.497 sec comparing with the previously published case when the values of S2, h2 and hd were set to 4.5, 0.3 and 0.2 sec, respectively. Also the results of sensitivity analysis showed that S2 and h2 had considerable influence on the SR while these variables were not so sensitive to the MT.

• 센서학회지
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• 제1권2호
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• pp.155-163
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• 1992

위상배열 안테나 레이다에서는 기계적 관성에 관계없이 레이다 빔의 신속한 조향이 가능하기 때문에 측정을 원하는 목표와 그 목표에 대한 측정시간, 측정표본속도를 선택적으로 취할 수 있게 된다. 이 논문에서는 주어진 측정 파라미터에 대해 이러한 위상배열 레이다 시스템을 위한 3차원 가변 포본화 빈도 추적 필터를 설계했다. 이 추적 필터는 추적목표의 탐지확률을 적정한 값 이상으로 유지하기 위해서 목표의 각도 예측오차를 안테나 빔 폭의 일정한 비율이내로 줄일 수 있어야 한다. 여기서 설계한 추적 필터는 이러한 요구를 만족하는 범위에서 표본화 빈도를 낮출 수 있도록 목표까지의 거리와 기동에 따라 표본화 빈도를 선택하게 된다. 이 추적 필터설계의 타당성은 여러가지 기동목표에 대한 수치실험을 통해 확인했다.

• 한국정밀공학회지
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• 제31권6호
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• pp.483-489
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• 2014

In this study, experiments were conducted for micro pattern printing to combine solution atomization process and stencil printing based on electrospray deposition. The stencil mask fabricated by etching the photosensitive glass placed below 0.3 mm distance to substrate has 100 um line width. The process parameters of electrospray deposition system for the atomization of the solution are applied voltage and supply flow rate of the solution. Meniscus angle of cone-jet was optimized by varying the supply flow rate from 0.3 ml/hr to 0.7 ml/hr. Voltage condition was verified having symmetric cone-jet angle and no pulsation at 8.5 kV applied voltage. In addition, a number of micro patterns are printed using a single 1 step process by solution atomization process. Variable line width of approximate 100 um was confirmed by changing conditions of solution atomization regardless of the pattern size of stencil mask.

• 대한기관식도과학회지
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• 제4권1호
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• pp.91-95
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• 1998

Background： Laryngeal cancer, the most common malignancy of head and neck, is being detected and treated in earlier and more effectively due to introduction of endoscope, continuous development of radiographic technology, and advancement in new surgical techniques such as laser surgery and conservation laryngeal surgery Objectives To compare the different treatment results for early laryngeal cancer to determine which methos provides the good prognosis. Materials and Methods： Retrospective study was done for 135 patients with early laryngeal squamous cell carcinoma(Stage I or II) who were treated at our institute between 1989 to 1996. There were 105 patients with glottic cancer(Stage I: 68 patients, Stage II：37 Patients) and 30 patients with supraglottic cancer(Stage I: 12 patients, Stage II：18 patients) Initial treatment included radiation therapy for 54 patients, endoscopic laser surgery for 8 patients, laryngofissure and cordectomy for 8 patients, vertical partial laryngectomy for 37 patients, supraglottic laryngecomy for 14 patients and supracricoid laryngectomy for 5 patiens, and total laryngectomy for 9 patients. Results : Salvage treatments, such as total laryngectomy, conservation laryngeal surgery, radiation therapy and neck dissection were performed for initial treatment failure with 9 patients after radiation therapy, 8 patients after conservation laryngeal surgery, 2 patients after endoscopic laser and 3 patients after total laryngectomy. Overall 3-year survival rate for glottic 71 was 92.4%, glottic f 84.3%, supraglottic 7172.7%, and supraglottic f was 63.%%. However, survival rate of the same stage was variable according to the choice of initial treatment. Conclusion New classification of the early laryngeal cancer was necessary and helpful for the choice of the initial treatment.

• 산경연구논집
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• 제12권1호
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• pp.15-30
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• 2021

Purpose: Year of 2020, COVID-19 has been changing the people's everyday life to ways never been thought of before all over the world. The IT and electronic industry, the methods of supplying goods and services have been changed from contact to un-tact environments based on un-tact systems very rapidly. COVID-19 has been striking the tourism and the travel industry, especially the airline and hotel industry of which services are provided by human. For the passenger service of airliner, automation has been propelled and un-tact style of service has become mainstreams except cabin service since 2000's. For passenger transportation, due to traffic regulations and exclusions etc., switching to new ways is not easy. However, under the new environment made by COVID-19, kiosk check-in, web check-in and mobile check-in has become more important. In this study, the characteristics of airline customers using mobile goods are investigated to find ways to raise the rate of utilizing mobile check-in and to increase the efficiency of boarding process. Research design, data, and methodology: Considering the COVID-19 environment, survey was done by online research company. The research model is designed to integrate the user characteristics and usage/purchase motive and technology acceptance theory. Especially considering infectious diseases prevention, concern of safety is adopted as one of the usage motive variable. Results: Extraversion or conscientiousness characteristics prefers counter check-in(contact service), while openness characteristics prefers mobile check-in(un-tact service). Concern of safety for infectious disease shows strong non-preference on counter check-in. Conclusions: Regarding service type regardless of type of the industry, automation and un-tact have been mainstreams due to high costs of labor, efficiency and standardization issue, etc., and COVID-19 has given impetus to them. For airliner, un-tact service including boarding process service has been more and more important. To raise the rate of un-tact service use, the characteristics of the user should be analyzed first. The study results indicate that for extraversion or conscientiousness, some kinds of methods to induce them to use un-tact service more are needed.

• 한국해양공학회지
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• 제36권5호
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• pp.313-325
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• 2022

Recently around the world, coastal erosion is paying attention as a social issue. Various constructions using low-crested and submerged structures are being performed to deal with the problems. In addition, a prediction study was researched using machine learning techniques to determine the wave attenuation characteristics of low crested structure to develop prediction matrix for wave attenuation coefficient prediction matrix consisting of weights and biases for ease access of engineers. In this study, a deep neural network model was constructed to predict the wave height transmission rate of low crested structures using Tensor flow, an open source platform. The neural network model shows a reliable prediction performance and is expected to be applied to a wide range of practical application in the field of coastal engineering. As a result of predicting the wave height transmission coefficient of the low crested structure depends on various input variable combinations, the combination of 5 condition showed relatively high accuracy with a small number of input variables defined as 0.961. In terms of the time cost of the model, it is considered that the method using the combination 5 conditions can be a good alternative. As a result of predicting the wave transmission rate of the trained deep neural network model, MSE was 1.3×10^-3, I was 0.995, SI was 0.078, and I was 0.979, which have very good prediction accuracy. It is judged that the proposed model can be used as a design tool by engineers and scientists to predict the wave transmission coefficient behind the low crested structure.

• 한국안광학회지
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• 제17권4호
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• pp.381-388
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• 2012

목적: 본 연구에서는 반복적인 건조에 의해 유발되는 실리콘 하이드로겔 렌즈의 형태 변화 및 착용시의 자 타각적 증상의 변화에 대해 알아보고자 하였다. 방법: 재질 혹은 두께가 다른 실리콘 하이드로겔 렌즈를 4회씩 건조하고 수화시킨 후 전체 직경과 베이스커브의 변화를 비교하였으며, 건조되었던 실리콘 하이드로겔 렌즈를 착용한 후 착용자의 자각적 증상 및 비침입성 눈물막 파괴시간과 순목횟수를 측정하였다. 결과: 반복되는 건조와 수화로 인하여 모든 실리콘 하이드로겔 렌즈의 전체 직경과 베이스커브가 증가하였다. 전체 직경과 베이스커브가 변하는 정도는 재질에 따라 각기 상이하였으며 두꺼운 렌즈에서는 건조수화 횟수에 따라 불규칙적인 변화가 나타났다. 실리콘 하이드로겔 렌즈의 재질이나 두께에 관계없이 건조수화 과정을 거친 렌즈를 착용하였을 때에는 착용자의 비침입성 눈물막 파괴시간은 감소하였으며, 순목횟수는 증가하였다. 또한, 반복적인 건조수화는 렌즈의 착용감에도 영향을 미쳐 가려움, 통증, 자극감, 이물감, 건조감이 증가하는 경향이 있었다. 결론: 본 연구 결과를 통하여 반복적인 건조수화로 실리콘 하이드로겔 렌즈의 형태 변화 및 이에 따른 착용감 저하 유발을 확인하였으므로 건조한 환경에 대하여 강한 내구성을 가지는 실리콘 하이드로겔 콘택트렌즈의 개발 필요성을 제안할 수 있다.