• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• 제14권4호
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• pp.247-256
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• 2021

In this paper, we propose a packet loss concealment (PLC) algorithm using pitch harmonic motion prediction and adaptive signal amplitude prediction and. The spectral motion prediction method divides the spectral motion of the previous usable frame into predetermined sub-bands to predict and restore the motion of the lost signal. In the proposed algorithm, the speech signal is classified into voiced and unvoiced sounds. In the case of voiced sounds, it is further divided into pitch harmonics using the pitch frequency to predict and restore the pitch harmonic motion of the lost frame, and for the unvoiced sound, the lost frame is restored using the spectral motion prediction method. When the continuous loss of speech frames occurs, a method of adjusting the gain using the least mean square (LMS) predictor is proposed. The performance of the proposed algorithm was evaluated through the objective evaluation method, PESQ (Perceptual Evaluation of Speech Quality) and was showed MOS 0.1 improvement over the conventional method.

• Journal of the Korean Society of Safety
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• 제37권6호
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• pp.118-127
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• 2022

This study analyzes the characteristics of occupational accidents of food delivery via motorcycle in terms of accident probability and work-days. Depending on their employment status, food-delivery workers were divided into "employed" workers (who work for restaurants) and "special-type" workers (who work for delivery platforms). Collected data include occupational accident-information during the last two years (1,468 cases for employed workers and 4,899 cases for special-type workers) and their risk information such as age, work experience, accident location, season of the accident, and weather conditions. The study finds that special-type workers had a significantly higher accident probability for the younger age group (80.8%), while employed workers had more accidents in both 20's or younger (34.9%) and 50's or older (25.4%). The number of work-days-lost was higher for special-type workers with less work experience, and it decreased with increasing work experience. Moreover, the chance for accidents was higher at night time (55%) than for day time (45%) for special-type workers as well as for employed workers. The number of work-days-lost was higher in foreign workers (180.79 days) than in Korean workers (121.44 days). Accident probability (30.7%) and work-days-lost (136.2 days) was higher in winter than in other seasons. In addition, accidents-per-day was higher on snowy days (12.7 cases per day) than rainy (8.1) and windy days (7.1). In addition, it was found that deadly accidents mainly caused injuries to face, head, and chest, while non-deadly accidents affected mainly the legs and feet. This study enables the development of better policies to prevent accidents of food delivery workers.

• Journal of Hospice and Palliative Care
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• 제26권3호
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• pp.126-139
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• 2023

Purpose: This study aimed to analyze interventions for bereaved families and evaluate their effectiveness, with the ultimate goal of supporting evidence-based nursing for bereaved families. Methods: Research trends were identified based on a search of domestic databases from January 2000 to December 2022, and a meta-analysis was conducted on interventions for bereaved families. Forty-five papers were selected, and information was extracted on participants, research design, and interventions. A meta-analysis of seven papers was performed, and the effect size was calculated. Results: Fourteen papers dealt with interventions for middle-aged women who had lost their spouses, 20 used qualitative research methods, and 20 were on art therapy programs. Thirty studies had fewer than 10 participants, and most interventions had 60~120 minutes per session and 9~16 sessions in total. There were seven randomized controlled trials, and all studies included in the quality evaluation showed a low risk of bias. Four papers measured grief as an outcome, and the effect size was -1.9577 (95% CI: -2.9206 to -0.9947), indicating that the treatment significantly decreased grief (P<0.001). Six papers measured depression as an outcome, and the effect size was -1.6775 (95% CI: -2.1835 to -1.1716), showing that the treatment significantly decreased depression (P<0.001). Conclusion: Intervention programs for bereaved families were shown to be effective in relieving grief and depression. However, programs should be developed that target middle-aged men who have lost their spouses and children who have lost their parents. Randomized controlled trials should also be conducted on interventions to reduce grief and depression.

• Journal of Environmental Health Sciences
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• 제49권3호
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• pp.149-158
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• 2023

Background: Injury is one of the major health problems in South Korea. Few studies have evaluated both intentional and unintentional injury when investigating the association between exposure to air pollutants and injury. Objectives: We aimed to explore the association between short-term exposure to ambient air pollution and years of life lost (YLLs) due to injury. Methods: Data on daily YLLs for 2002~2019 were obtained from the the Death Statistics Database of the Korean National Statistical Office. This study estimated short-term exposure to particulate matter with an aerodynamic diameter of <10 ㎛ (PM₁₀), particulate matter with an aerodynamic diameter of <2.5 ㎛ (PM_2.5), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO), and ozone (O₃). This time series study was conducted using a generalized additive model (GAM) assuming a Gaussian distribution. We also evaluated a delayed effect of ambient air pollution by constructing a lag structure up to seven days. The best-fitting lag was selected based on smallest generalized cross validation (GCV) value. To explore effect modification by intentionality of injury (i.e., intentional injury [self-harm, assault] and unintentional injury), we conducted stratified subgroup analyses. Additionally, we stratified unintentional injury by mechanism (traffic accident, fall, etc.). Results: During the study period, the average daily YLLs due to injury was 307.5 years. In the intentional injury, YLLs due to self-harm and assault showed positive association with air pollutants. In the unintentional injury, YLLs due to fall, electric current, fire and poisoning showed positive association with air pollutants, whereas YLLs due to traffic accident, mechanical force and drowning/submersion showed negative associations with air pollutants. Conclusions: Injury is recognized as preventable, and effective strategies to create a safe society are important. Therefore, we need to establish strategies to prevent injury and consider air pollutants in this regard.

• Journal of the Korea institute for structural maintenance and inspection
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• 제13권5호통권57호
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• pp.109-120
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• 2009

This paper introduces a new method to estimate the loss of prestressing force for the externally prestressing tendon. The proposed method that combines of HGA and FEM is able to identify the lost tensile force of a externally prestressed tendon. The identification variables of the proposed method is a exteranlly prestressed tendon of tension, effective nominal diameter, mass per unit length and Rayleigh damping coefficients. First of all, a finite element model system is constructed to consider the effect of damping, and these variables are identified using inverse analysis technique - updating algorithm. Finally, throughout total 3 cases of numerical tests, the numerical propriety of the proposed method is verified. Here, it is seen that the errors in the estimated variables by the proposed method are about 1% except in the case of Rayleigh damping coefficients.

• Journal of the Korea institute for structural maintenance and inspection
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• 제13권5호통권57호
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• pp.121-132
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• 2009

This paper introduces an experimental verification and a field application of the proposed technique using the combination of FEM and HGA about the loss prestressing force of an exteranl tendon by above same authors. The vibration tests have been conducted by using a laboratory models and the externally prestressed tendon at the field and the natural frequencies are extracted from the vibration tests. The proposed technique based on the extracted natural frequencies is applied. It is seen that the errors in the tension and lost prestressing force by proposed technique are about 4% from a laboratory model test. For the model verification at field, exact modeling has beem made with Rayleigh damping. It is seen that the error in the tension by proposed technique is less than 1% and the estimated lost prestressing force converges less than the exact value.

• Journal of the Korean Society for Library and Information Science
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• 제58권3호
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• pp.145-168
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• 2024

This study analyzed the current status of late fee policies for overdue books in public libraries in the United States and Korea and derived measures to improve the late fee policy in public libraries in Korea. Therefore, this study analyzed the current status of late fee policies in public libraries in Seoul, Korea. The results indicated that 14.8% of public library operators and 21.6% of public libraries in Seoul had late fee policies. In the US, the American Library Association and major public libraries were found to have recently eliminated late fees. The main justification for this policy change was their recognition of late fees as a form of social inequality. In fact, this study confirmed that the elimination of late fees led to users' increased access to information. This study also found that public libraries in the US turned books not returned after a certain period into lost items and imposed fines for lost items. In conclusion, this study suggested integrating measures for late fees and lost items to manage non-returned books and clarifying the legal basis for such measures.

• Journal of Bio-Environment Control
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• 제25권2호
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• pp.106-110
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• 2016

In this study, a planting density-growth-harvest (PGH) chart was developed to easily read the growth and harvest factors such as crop growth rate, relative growth rate, shoot fresh weight, shoot dry weight, harvesting time, marketable rate, and marketable yield of common ice plant (Mesembryanthemum crystallinum L.). The plants were grown in a nutrient film technique (NFT) system in a closed-type plant factory using fluorescent lamps with three-band radiation under a light intensity of $140{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 12 h. Growth and yield were analyzed under four planting densities ($15{\times}10cm$, $15{\times}15cm$, $15{\times}20cm$, and $15{\times}25cm$). Shoot fresh and dry weights per plant increased at a higher planting density until reached an upper limit and yield per area was also same tendency. Crop growth rate, relative growth rate and lost time were described using quadratic equation. A linear relationship between shoot dry weight and fresh weights was observed. PGH chart was constructed based on the growth data and making equations. For instance, with within row spacing (= 20 cm) and fresh weight per plant at harvest (= 100 g), we can estimate all the growth and harvest factors of common ice plant. The planting density, crop growth rate, relative growth rate, lost time, shoot dry weight per plant, harvesting time, and yield were $33plants/m^2$, $20g{\cdot}m^{-2}{\cdot}d^{-1}$, $0.27g{\cdot}g^{-1}{\cdot}d^{-1}$, 22 days, 2.5 g/plant, 26 days after transplanting, and $3.2kg{\cdot}m^{-2}$, respectively. With this chart, we could easily obtain the growth factors such as planting density, crop growth rate, relative growth rate, lost time and the harvest factors such as shoot fresh and dry weights, harvesting time, marketable rate, and marketable yield with at least two parameters, for instance, planting distance and one of harvest factors of plant. PGH charts will be useful tools to estimate the growth and yield of crops and to practical design of a closed-type plant production system.

• The Korean Journal of Emergency Medical Services
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• 제3권1호
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• pp.65-76
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• 1999

Objectives: This study sought to examine the impact of alcohol use and misuse on mortality in korea during the 1991-l997. Methods: Alcohol-Related Disease Impact estimation software and Korea vital statistics data were used to calculate alcohol related-mortality, mortality rates, and YPLL(years of potential life lost). The major findings are as follows : An estimated 23,528 Korean died during 1997 from causes related to alcohol. Such deaths accounted for 17,052(12.60%) of all deaths for men and 6,206(5.88%) for women. Motor vehicle accidents were major contributors to the total estimated number of alcohol related deaths and years of potential life lost before age 65. Alcohol related mortality rates were significantly higher for men. For men, major causes of the deaths were motor vehicle accidents(4,147 deaths, 17.90 per 100,000 population), cancer of the stomach(1,467 deaths, 16.60 per 100,000 population) and chronic liver diseases and cirrhosis(1,233 deaths, 13.10). For women, the largest contributors to alcohol related mortality were motor vehicle accidents(1,509 deaths, 6.61), cerebrovascular diseases(1,114 deaths, 11.3) and cancer of the stomach(810 deaths, 8.24). Kleinman's method was used for obtaining on regional(Dongs, ups and Myons) differential of the alcohol related mortality in 1995. In general, The alcohol-related death rate for men was significantly higher than that for women, and the rate for ups and myons was significantly higher than that for dongs During 1997, approximately 356,667(male: 282, 510, female: 74, 157)YPLL to age 65 and 572,708(male:424,338, female:148,370)YPLL to life expectancy were attributable to alcohol related causes. Men accounted for 79% of the total YPLL to age 65 and 74% of the total YPLL to life expectancy The major contributors to these alcohol related years lost were the diagnostic categories of unintentional injuries. Particullary, In male, Motor vehicle accidents and accidental drowning-YPLL are considerably higher for other causes. Male-female YPLL differentials were greatest for mental disorder. Male-female mean-YPLL to age 65, accidental drowning(male;36.47, female;37.67) is higher for other causes. In both sexes, The YPLL and M-YPLL to life expectancy was significantly higher than the YPLL and M-YPLL to life expectancy.

• Journal of KIISE:Computer Systems and Theory
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• 제29권6호
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• pp.331-339
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• 2002

This paper presents a garbage collection protocol for checkpoints and message logs which are staved on the stable storage or volatile storage for fault tolerancy. The previous works of garbage collections in coordinated checkpointing protocol delete all the checkpoints except for the last checkpoints on earth processes. But implemented in top of reliable communication protocol like as TCP/IP, rollback recovery protocol based on only last checkpoints makes sympathetic rollback. We show that the old checkpoints or message logs except for the last checkpoints have to be preserved in order to replay the lost message. And we define the conditions for garbage collection of checkpoints and message logs for lost messages and present the garbage collection algorithm for checkpoints and message logs in coordinated checkpointing protocol. Since the proposed algorithm uses process information for lost message piggybacked with messages, the additional messages for garbage collection is not required The proposed garbage collection algorithm makes 'the lazy garbage collectioneffect', because relying on the piggybacked checked checkpoint information in send/receive message. But 'the lazy garbage collection effect'does not break the consistency of the whole systems.