• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.57-63
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• 1994

This paper summarizes recent research in the use of the psychophysical method of adjustment to establish acceptable parameters for upper extremity work activities. Results from these studies show that this psychophysical approach can provide reliable guidelines based upon realistic job conditions which involve one or more risk factors for cumulative trauma. It is also shown that this method provides advantages over other psychophysical methods as well as current biomechanical and physioligical criteria.

• Nuclear Engineering and Technology
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• v.55 no.10
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• pp.3515-3524
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• 2023

A reinforcement learning framework is proposed for the control problem of outlet steam pressure of the once-through steam generator(OTSG) in this paper. The double-layer controller using Proximal Policy Optimization(PPO) algorithm is applied in the control structure of the OTSG. The PPO algorithm can train the neural networks continuously according to the process of interaction with the environment and then the trained controller can realize better control for the OTSG. Meanwhile, reinforcement learning has the characteristic of difficult application in real-world objects, this paper proposes an innovative pretraining method to solve this problem. The difficulty in the application of reinforcement learning lies in training. The optimal strategy of each step is summed up through trial and error, and the training cost is very high. In this paper, the LSTM model is adopted as the training environment for pretraining, which saves training time and improves efficiency. The experimental results show that this method can realize the self-adjustment of control parameters under various working conditions, and the control effect has the advantages of small overshoot, fast stabilization speed, and strong adaptive ability.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.3
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• pp.135-152
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• 2018

The purpose of this study is to propose an optimal fusion method of aerial multi - sensor data to improve the accuracy of land cover classification. Recently, in the fields of environmental impact assessment and land monitoring, high-resolution image data has been acquired for many regions for quantitative land management using aerial multi-sensor, but most of them are used only for the purpose of the project. Hyperspectral sensor data, which is mainly used for land cover classification, has the advantage of high classification accuracy, but it is difficult to classify the accurate land cover state because only the visible and near infrared wavelengths are acquired and of low spatial resolution. Therefore, there is a need for research that can improve the accuracy of land cover classification by fusing hyperspectral sensor data with multispectral sensor and aerial laser sensor data. As a fusion method of aerial multisensor, we proposed a pixel ratio adjustment method, a band accumulation method, and a spectral graph adjustment method. Fusion parameters such as fusion rate, band accumulation, spectral graph expansion ratio were selected according to the fusion method, and the fusion data generation and degree of land cover classification accuracy were calculated by applying incremental changes to the fusion variables. Optimal fusion variables for hyperspectral data, multispectral data and aerial laser data were derived by considering the correlation between land cover classification accuracy and fusion variables.

• Journal of Korea Game Society
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• v.11 no.4
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• pp.143-149
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• 2011

This paper presents a novel camera tracking method based on model with multiple planes. The proposed algorithm detects QR code that is one of the most popular types of two-dimensional barcodes. A 3D model is imported from the detected QR code for augmented reality application. Based on the geometric property of the model, the vertices are detected and tracked using optical flow. A clipping algorithm is applied to identify each plane from model surfaces. The proposed method estimates the homography from coplanar feature correspondences, which is used to obtain the initial camera motion parameters. After deriving a linear equation from many feature points on the model and their 3D information, we employ DLT(Direct Linear Transform) to compute camera information. In the final step, the error of camera poses in every frame are minimized with local Bundle Adjustment algorithm in real-time.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.14
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• pp.5669-5673
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• 2015

Background: Breast cancer is the most prevalent kind of cancer among women in Iran. Regarding the importance of cancer prevention and considerable variation of breast cancer incidence in different parts of the country, it is necessary to recognize regions with high incidence of breast cancer and evaluate the role of potential risk factors by use of advanced statistical models. The present study focussed on incidence of breast cancer in Iran at the province level and also explored the impact of some prominent covariates using Bayesian models. Materials and Methods: All patients diagnosed with breast cancer in Iran from 2005 to 2008 were included in the study. Smoking, fruit and vegetable intake, physical activity, obesity and the Human Development Index (HDI), measured at the province level, were considered as potential modulating factors. Gamma-Poisson, log normal and BYM models were used to estimate the relative risk of breast cancer in this ecological investigation with and without adjustment for the covariates. Results: The unadjusted BYM model had the best fit among applied models. Without adjustment, Isfahan, Yazd, and Tehran had the highest incidences and Sistan- Baluchestan and Chaharmahal-Bakhtiari had the lowest. With the adjusted model, Khorasan-Razavi, Lorestan and Hamedan had the highest and Ardebil and Kohgiluyeh-Boyerahmad the lowest incidences. A significantly direct association was found between breast cancer incidence and HDI. Conclusions: BYM model has better fit, because it contains parameters that allow including effects from neighbors. Since HDI is a significant variable, it is also recommended that HDI should be considered in future investigations. This study showed that Yazd, Isfahan and Tehran provinces feature the highest crude incidences of breast cancer.

• Journal of Ecology and Environment
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• v.29 no.5
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• pp.479-484
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• 2006

Ecophysiological parameters of non-transgenic sweetpotato (NT) and transgenic sweetpotato (SSA) plants were compared to evaluate their resistance to multiple environmental stresses. Stomatal conductance and transpiration rate in NT plants decreased markedly from Day 6 after water was withheld, whereas those values in SSA plants showed relatively higher level during this period. Osmotic potential in SSA plants was reduced more negatively as leaf water potential decreased from Day 8 after dehydration treatment, while such reduction was not shown in NT plants under water stressed condition. SSA plants showed less membrane damage than in NT plants. As water stress and high light stress, were synchronously applied to NT and SSA plants maximal photochemical efficiency of PS II ($F_v/F_m$) in NT plants markedly decreased, while that in SSA plants was maintained relatively higher level. This trend of changes in $F_v/F_m$ between SSA plants and NT plants was more conspicuous as simultaneously treated with water stress, high light and high temperature stress. These results indicate that SSA plants are more resistive than NT plants to multiple environmental stresses and the enhanced resistive characteristics in SSA plants are based on osmotic adjustment under water stress condition and tolerance of membrane.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.293-296
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• 2008

Creep and shrinkage in concrete structures are very complex phenomena in which various uncertainties exist with regard to inherent material variations as well as modeling uncertainties. The creep and shrinkage models which are capable of predicting long-term structural response are specified in design codes such as ACI 209-92, CEB-FIP Model Code 90, etc. However, in the prediction formulas of creep and shrinkage effects of concrete, various kinds of parameters are involved to express the characteristics of concrete under consideration (i.e. the proportion of concrete, the shape of the structure, relative humidity, etc.). And the predicted values from each design code under same environment differ from each other. To predict the characteristics of concrete, the long-term experiments of creep and shrinkage is necessary but this is not suitable for a construction field. In this study, adjustment method of creep coefficient using sensitivity analysis is proposed to predict creep coefficient of concrete exactly and it is checked up on the validity of the predicting method by comparing to the assumed value and predicted one.

• Korean Journal of Remote Sensing
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• v.25 no.2
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• pp.133-143
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• 2009

This paper describes differences of performance when the orbit attitude model is applied to the respective images obtained from two different types of satellite. The one is Spot that rotates its pointing mirror and the other is Kompsat-2 that rotates its whole body when they obtain imagery for target. Our research scope is limited to the orbit-attitude model only as its good performance was proved in prior investigation. Model performances between two images were compared with sensor model accuracy and 3D coordinates calculation. The results show performances of the orbit-attitude model for each image type were different. For Spot imagery, the model required attitude angle to be included as adjustment parameters. For Kompsat-2 imagery, the model required high-order parameter for adjustment. This implies that satellite sensor model may be applied differently in accordance with platform's attitude control scheme and accuracy. Understanding of this information can be a base for improvement and development of model and application for new satellite images.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.4
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• pp.338-344
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• 2018

This article describes cases of applying non-surgical treatment including scaling and root planing, occlusal adjustment and tooth splinting of periodontally compromised lower anterior incisors Clinical and radiographic evaluations were performed over a 1-3-year period. All clinical parameters and radiographic bone levels improved in both cases. Dramatic regeneration of alveolar bone and lamina dura were observed on radiographic images, and no specific complications occurred during the follow-up period. Within the limitations of this study, these cases demonstrated the possibility of tooth rescue through non-surgical treatment and splinting of periodontally compromised teeth typically considered for extraction.

• Journal of Drive and Control
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• v.18 no.4
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• pp.19-27
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• 2021

A bunker bed is a type of furniture that efficiently utilizes a narrow indoor space by having a high bed and using the empty space below as a living and storage space. The demand for multi-purpose furniture is increasing due to the recent increase in single-person households and wide-spread shared accommodation. According to the consumer research, one of the major drawbacks of a bunker bed was to get on and off the bed through a ladder or stairs. In order to overcome these problems, it was confirmed that the height adjustment function that can easily adjust the minimum and maximum heights of the bed was necessary. In this study, a height adjustable bunker bed was designed by using a gas spring that generates a repulsive force by the compressed gas inside. The design process consisted of the following three steps: Firstly, the hysteresis characteristics due to a friction and spring constant of a commercial gas spring were confirmed by measuring the repulsive force vs. compressed displacement. Secondly, requirements of the vertical lifting force exerted on the bed against gravity force were derived. Finally, the height-adjustable bed using the four-bar link mechanism was designed with 4 parameters so that the bed weight of 60-70 kgf could be adjusted to 800 mm in height by an affordable initial operation force. The performance was verified through prototype production and the results of vertical displacement and force to move were nearly the same as designed. In addition, an electrically operated height-adjustable bed was also designed with linear actuators and the performance was proved with the prototype.