• Journal of the Ergonomics Society of Korea
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• v.27 no.3
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• pp.15-22
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• 2008

The purpose of this study was to define the effects of noise and background music on the trunk muscle fatigue during dynamic lifting and lowering tasks. Six healthy male subjects with no prior history of low back disorders participated in this study. The participants were exposed to two levels of background noise such as 40dB noise and 90dB noise and three levels of background music such as no music, slow music, and fast music. Six different combinations of background noise and background music were played while the participants were performing the lifting task at 15% level of Maximum Voluntary Contraction. Electromyography signals from six muscles were collected and fatigue levels were analyzed quantitatively. In results, the 90dB noise increased trunk muscle fatigue and slowed down the recovery. The trunk muscle fatigue was the lowest when the fast music was played for as background. After recovery, the 90dB noise increased trunk muscle fatigue. The trunk muscle fatigue was the lowest when the slow music was played for as background. The results can be useful to manage the cumulative fatigue of trunk muscles due to background noise and music during repetitive lifting and lowering tasks in industry.

• Journal of the Korea Computer Graphics Society
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• v.25 no.5
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• pp.1-9
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• 2019

In this paper, we propose a video enhancement method using generative adversarial networks to remove raindrops and restore the background information on the removed region in the coastal wave video imagery distorted by raindrops during rainfall. Two experimental models are implemented: Pix2Pix network widely used for image-to-image translation and Attentive GAN, which is currently performing well for raindrop removal on a single images. The models are trained with a public dataset of paired natural images with and without raindrops and the trained models are evaluated their performance of raindrop removal and background information recovery of rainwater distortion of coastal wave video imagery. In order to improve the performance, we have acquired paired video dataset with and without raindrops at the real coast and conducted transfer learning to the pre-trained models with those new dataset. The performance of fine-tuned models is improved by comparing the results from pre-trained models. The performance is evaluated using the peak signal-to-noise ratio and structural similarity index and the fine-tuned Pix2Pix network by transfer learning shows the best performance to reconstruct distorted coastal wave video imagery by raindrops.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.5
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• pp.44-54
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• 2008

The objective of this research is to develop a measurement instrument for service recovery quality in the Internet commerce setting. To this same end, Parasuraman et al.(2005) have devised a scale called E-RecS-QUAL, which we revised and supplemented to develop another instrument named eSR-Q. To guarantee its reliability and validity, this instrument went through the refinement and validation processes for internal consistency and construct validity in terms of convergent, discriminant, and nomological validity. Our final scale consists of four dimensions including responsiveness, compensation, contact, and apologies altogether with fourteen measures. Overall, this research deals with the related research background, the scale development and validation processes, its limitations, and future research directions.

• Journal of the Ergonomics Society of Korea
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• v.36 no.5
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• pp.535-543
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• 2017

Objective: This study was designed to identify factors affecting pilots' +Gz tolerance recovery from +Gz induced exhaustion. Background: +Gz tolerance of pilots has been considered as a crucial factor to fly the modern high performance fighter aircrafts. However, the factors affecting pilots' G-tolerance recovery from +Gz induced exhaustion have not been examined in the acceleration research community. Method: A centrifuge profile consisting of a high +Gz run for pilot's exhaustion and a low +Gz run for pilot's recovery and another high +Gz runs for pilot's second exhaustion was designed. The subjects' +Gz tolerance recovery ratio was measured by ratio of second high +Gz run time to the first high +Gz run time. The subjects' +Gz tolerance recovery rate was measured by dividing the subjects' +Gz tolerance recovery ratio by the low +Gz run time. The subjects' G-tolerance recovery rate was analyzed with respect to the subjects' personal factors including subjects' anthropometric and physiologic characteristics, flight time, flying aircraft type and so on. Results: The subjects' previous three-month flight hours (r=-0.336, p=0.039), six-month flight hours (r=-0.403, p=0.012) and one-year flight hours (r=-0.329, p= 0.044) correlated with the subjects' G-tolerance recovery rate. Conclusion: The subjects' G-tolerance recovery rate is clearly related to the subjects' previous flight hours. However, the subjects' anthropometric and physiologic characteristics do not show any statistically significant correlation with the subjects' G-tolerance recovery rate. Application: This research provides a safety critical insight to aviation community by identifying the factors to affect the gravity-induced loss of consciousness (GLOC) of pilots.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.12
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• pp.6043-6062
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• 2019

Low-rank matrix decomposition has shown its capability in many applications such as image in-painting, de-noising, background reconstruction and defect detection etc. In this paper, we consider the texture background of rail track images and the sparse foreground of the defects to construct a low-rank matrix decomposition model with block sparsity for defect inspection of rail tracks, which jointly minimizes the nuclear norm and the 2-1 norm. Similar to ADM, an alternative method is proposed in this study to solve the optimization problem. After image decomposition, the defect areas in the resulting low-rank image will form dark stripes that horizontally cross the entire image, indicating the preciselocations of the defects. Finally, a two-stage defect extraction method is proposed to locate the defect areas. The experimental results of the two datasets show that our algorithm achieved better performance compared with other methods.

• Journal of KIISE:Software and Applications
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• v.29 no.11
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• pp.767-774
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• 2002

Conventional research on image restoration has focused on restoring degraded images resulting from image formation, storage and communication, mainly in the signal processing field. Related research on recovering original image information of caption regions includes a method using BMA(block matching algorithm). The method has problem with frequent incorrect matching and propagating the errors by incorrect matching. Moreover, it is impossible to recover the frames between two scene changes when scene changes occur more than twice. In this paper, we propose a method for recovering original images using EBMA(Extended Block Matching Algorithm) and a region compensation method. To use it in original image recovery, the method extracts a priori knowledge such as information about scene changes, camera motion and caption regions. The method decides the direction of recovery using the extracted caption information(the start and end frames of a caption) and scene change information. According to the direction of recovery, the recovery is performed in units of character components using EBMA and the region compensation method. Experimental results show that EBMA results in good recovery regardless of the speed of moving object and complexity of background in video. The region compensation method recovered original images successfully, when there is no information about the original image to refer to.

• Journal of Veterinary Science
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• v.23 no.5
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• pp.66.1-66.8
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• 2022

Background: Prospective clinical study of blood lactate concentration in horses undergoing colic surgery is needed to determine utility in outcome prediction. Objectives: To evaluate venous lactate measurements in horses following colic surgery, including immediately after anesthetic recovery and daily throughout hospitalization, as well as to determine if lactate concentrations were significantly higher in horses that developed postoperative complications or did not survive to hospital discharge. Methods: Horses > 1 year of age undergoing surgery for colic and recovered from general anesthesia were sampled. A portable lactate meter was used to measure venous samples collected immediately following anesthetic recovery and daily throughout hospitalization. Complications arising during hospitalization and survival to hospital discharge were recorded. Results: Fifty one horses were enrolled, ranging in age from 2 to 29 years. Lactate concentration immediately following anesthetic recovery was higher in horses that developed complications during hospitalization (p = 0.046). The odds of developing complications postoperatively were doubled for horses with a venous lactate concentration > 5 mmol/L. Lactate measurements in non-survivors were significantly higher compared to survivors by 96 h postoperatively (p < 0.006). Conclusions: Higher venous lactate concentrations in the postoperative colic period were associated with an increased risk of complications and death. Results suggest horses with higher venous lactate measurements in recovery are more likely to have postoperative complications, with the odds of developing complications doubled for horses with a venous lactate > 5 mmol/L. Evaluation of venous lactate could provide information on prognosis in the postoperative period for horses with surgical colic.

• Safety and Health at Work
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• v.13 no.1
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• pp.32-39
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• 2022

Background: Industrial accidents can determine the overall level and quality of the work environment in industries and companies that contribute to national economic development. Korea has transformed the country from an international aid recipient to a donor country, but it has ranked first among the Organisation for Economic Co-operation and Development member countries in the number of fatal industrial accidents. Little has been known about the policy effects in terms of the workers' insurance for their industrial accidents and rehabilitation. This study raises two research questions about the influence of workers' personal characteristics and vocational rehabilitation services on their return to workplaces. Methods: The study implements weighted logistic regression analysis using propensity score matching. This research utilizes the relevant dataset (3,924 persons) of Korea's industrial accident and insurance. Results: The findings show that the level of workers' awareness of health recovery and their counseling for rehabilitation by physicians had positive effects on their return to work. Environmental factors such as workers' job stability at the time of industrial accidents and the temporal effects of industrial accidents (e.g., the level of disability, their age) had negative impacts on their return to work. Conclusions: These findings have policy implications that the concentration of rehabilitation services for patients who have been mildly affected by industrial accidents would be effective in the short and medium term. The findings also highlight the necessity of ongoing policies about workers' vocational recovery with concrete evidence about policy impacts.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.2 no.6
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• pp.333-351
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• 2008

Transmission control protocols have to overcome common problems in wireless networks. TCP employing both packet loss discrimination mechanism and available bandwidth estimation algorithm, known as the good existing solution, shows significant performance enhancement in wireless networks. For instance, TCP New Jersey which exhibits high throughput in wireless networks intends to improve TCP performance by using available bandwidth estimation and congestion warning. Even though it achieves 17% and 85% improvements in terms of goodput over TCP Westwood and TCP Reno, respectively, we further improve it by exploring maximized available bandwidth estimation, handling bit-error-rate error recovery, and effective adjustment of sending rate for retransmission timeout. Hence, we propose TCP NJ+, showing that for up to 5% packet loss rate, it outperforms other TCP variants by 19% to 104% in terms of goodput when the network is in bi-directional background traffic.

• Quality Improvement in Health Care
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• v.7 no.1
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• pp.90-104
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• 2000

Background : This study was designed to assess the effects of information on the satisfaction of parents and families whose children underwent elective surgery in the Pediatric Operating Room. Methods : We measured parent and family satisfaction with information given before and after offering informational interventions. The data were collected from 510 patients parents and families whose children had undergone elective surgery in the Pediatric Operating Room of Seoul National University Hospital in Seoul. South Korea. The data collection ran from May 3. 1999 to May 30. 1999 and from September 6, 1999 to September 30, 1999. The research instrument consisted of four categories (pre-operative period, intra-operative period, post-operative period, others) and 24 questionnaires. SPSS was used to analyze the data. Results : The major findings of this study are summarized as follows: 1. Before surgery, the satisfaction with the following was increased: the explanations of the necessary preparation for the surgery (6.0%), the time the patient would enter the operating room (20.6%), the operative procedure (2.0%), and the use of the waiting room (10.0%). 2. During the operation, the satisfaction with the situation board (15.1%), public announcements in the waiting room (8.4%), and the answering of the families questions (12.2%) was increased. however, the satisfaction with the surgeons explanations of the surgical outcomes decreased by 8.3%, even though the frequency of these explanations increased by 5%. 3. After surgery, the satisfaction with the following was increased: the explanations of patient's status of recovery(10.3%) the time the patient would be moved from the recovery room (17.6%), how the patient would be transferred to the ward (19.2%), and post-operative care (6.3%). Conclusion : Based upon the above findings, we concluded that pre-, intra-, and post-operative informational interventions were effective in increasing the satisfaction of the parents and families of children undergoing elective surgery.