• ETRI Journal
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• 제43권3호
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• pp.447-458
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• 2021

The quality of experience (QoE) of video streaming is degraded by playback interruptions, which can be mitigated by the playout buffers of end users. To analyze the impact of playout buffer dynamics on the QoE of wireless adaptive hypertext transfer protocol (HTTP) progressive video, we model the playout buffer as a G/D/1 queue with an arbitrary packet arrival rate and deterministic service time. Because all video packets within a block must be available in the playout buffer before that block is decoded, playback interruption can occur even when the playout buffer is non-empty. We analyze the queue length evolution of the playout buffer using diffusion approximation. Closed-form expressions for user-perceived video quality are derived in terms of the buffering delay, playback duration, and interruption probability for an infinite buffer size, the packet loss probability and re-buffering probability for a finite buffer size. Simulation results verify our theoretical analysis and reveal that the impact of playout buffer dynamics on QoE is content dependent, which can contribute to the design of QoE-driven wireless adaptive HTTP progressive video management.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.952-959
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• 2022

Active construction work zones will result in longer travel time and/or longer travel distances for road users because of reduced speed limits and/or detours. This results in increased fuel consumption and increased emissions of harmful gases such as Carbon Monoxide (CO), Nitrogen Oxides (NOx), and Sulfur Oxides (SOx), which causes discomfort to the environment and road users around the work zone. The impact of such emissions should be considered while designing work zones or determining the number of days the roadway will be allowed to be closed partially or fully. This study develops a methodology to compute additional road user costs associated with such work zones. To achieve this goal, a) an extensive literature review is conducted, b) a framework to compute emission cost is developed, c) emission rates are computed for all counties (95) of the state of Tennessee, and d) a case study is conducted to demonstrate the use of the framework to estimate the additional impact of emission because of the work zone. For the case study conducted, the emission cost was computed to be $10,653.60 for the duration of the project. State DOTs can account for such road user costs while selecting contractors using A+B bidding. Accounting for such impact of emission will also indicate the agency's willingness to consider sustainability as a part of the business practices.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.975-983
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• 2022

This paper presents an innovative way of integrating scheduling and project controls with the environmental impact of a construction project to track, monitor, and manage environmental emissions at the activity level. As a starting point, scheduling and project controls help monitor the status of a project to provide an assessment of the duration and sequence of activities. Additionally, project schedules can also reflect resource allocation and costs associated with various phases of a construction project. Owners, contractors and construction managers closely monitor tasks or activities on the critical path(s) and/or longest path(s) calculated through network based scheduling techniques. However, existing industry practices do not take into account environmental impact associated with each activity during the life cycle of a project. Although the environmental impact of a project may be tracked in various ways, that tracking is not tied to the project schedule and, as such, generally is not updated when schedules are revised. In this research, a Cradle to Gate approach is used to estimate environmental emissions associated with each activity of a sample project schedule. The research group has also investigated the potential determination of scenarios of lowest environmental emissions, just as project managers currently determine scenarios with lowest cost or time. This methodology can be scaled up for future work to develop a library of unit emissions associated with commonly used construction materials and equipment. This will be helpful for project owners, contractors, and construction managers to monitor, manage, and reduce the carbon footprint associated with various projects.

• Asian Journal of Business Environment
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• 제14권3호
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• pp.1-11
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• 2024

Purpose: This study analyzes the impact of weather conditions, holidays, and sporting events on beer sales, providing insights for market strategy and inventory management in the beer industry. Research design, data and methodology: Beer types were classified into Lagers and Ales, with further subcategories. The study utilized weekly retail sales data from January 2018 to August 2020, provided by Nielsen Korea. An ARMAX model was employed for time-series analysis. Results: The analysis revealed that increasing temperatures positively influence sales of Pilsners and Pale Lagers. Conversely, higher precipitation levels negatively affect overall Lager sales. Among Ales, only Stout sales showed a significant decrease with increased rainfall. Sunshine duration did not significantly impact sales for any beer type. Humidity generally had little effect on beer sales, with the exception of Amber Lagers, which showed sensitivity to humidity changes. Holidays and sporting events were found to significantly boost sales across most beer types, although the specific impacts varied by beer category. Conclusions: This study offers a detailed analysis of how weather conditions and specific events influence different beer type sales. The findings provide valuable insights for breweries, beer processors, and retailers to optimize their market strategies and inventory management based on weather forecasts and seasonal events. By understanding the consumption patterns of each beer type in relation to environmental factors, businesses can better anticipate demand fluctuations and tailor their operations accordingly.

• 가정과삶의질연구
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• 제28권2호
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• pp.27-37
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• 2010

The purpose of the study was to analyze the constraints that are normally experienced before moving in the context of the household characteristics of households that had recently moved to newly-built apartments. The data for the analysis was collected through a self-administered questionnaire from July 1, 2008 to August 10, 2008. The sample consisted of 251 households in Ulsan living in an apartment complex who had moved within a year. The data from the sample was analyzed by descriptive statistics, factor analysis, and analysis of variance with Duncan's multiple range tests. The results are as follows. The constraints were categorized into information gathering, attractive housing characteristics, expectations of residential mobility, housing development and policies, and resources. Overall, the constraints did not have a huge impact on the performance of the residential mobility of the sample households. Resources, however, were the most influential factors among the five constraints followed by attractive housing characteristics, information gathering, etc. The constraints varied based on the demographic characteristics, such as the household size, duration of marriage, age of the household head, and the socio-economic characteristics, such as the education level of the household head, household income, and the number of mobility. As the number of family members increased, the age of the household head went up, or the level of education went down, the constraints on information gathering were affected in terms of performing residential mobility. Households with a middle aged head with a professional occupation were more constrained by the attractive characteristics of the housing. The impact of the resources related constraints was significantly different based on the number of family members, marriage duration, and the household head's age and occupation, and the number of mobility.

• 농업과학연구
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• 제44권2호
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• pp.254-260
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• 2017

The primary goals of this research were to evaluate the impact of diet supplemented with 25-hydroxyvitamin $D_3$ ($Hy{\cdot}D(R)$) on sow's body condition and reproduction performance. A total of sixteen multiparous sows [(Landrace ${\times}$ Yorkshire), average parity = $3.79{\pm}0.32$] and their litters were randomly allotted to 2 treatments to give 8 replicates per treatment. Diet treatments were randomized to receive a non-active (ND) or active 25-hydroxyvitamin $D_3$ (AD) diet (0.36 mg cholecalciferol/g) during pregnancy. The results of this experiment were observed at the gestation of d 58 - 75, d 76 - 95, d 96 - 110, and d 111 - 115. A corn-soybean meal-based diet was formulated to meet or exceed the nutrient requirements recommended by NRC (2012). Results indicated that the sows' farrowing duration was shortened (4.71, 5.38 h), and the average number of mummified fetuses decreased significantly (p < 0.05) in AD treatment compared with ND treatment (0.1, 0.5) while birth weight was significantly (p < 0.05) improved (1.44, 1.18 kg). There were no significant effects on body weight, backfat thickness, and fecal score during the gestation of sows in different phases (p > 0.05). And the total birth, stillbirth, live birth, and survival rates of the litter did not change (p > 0.05). The results of this study suggest that the farrowing duration of sow pigs will be shortened and the number of mummies will be decreased while their litters' body weight may be improved, if fed active 25-hydroxyvitamin $D_3$ (0.36 mg/g) during pregnancy phase.

• 대기
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• 제24권4호
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• pp.457-470
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• 2014

Thermodynamic conditions related with localized torrential rainfall in the middle west region of Korean peninsula are examined using radar rain rate and radiosonde observational data. Localized torrential rainfall events in this study are defined by three criteria base on 1) any one of Automated Synoptic Observing System (ASOS) hourly rainfall exceeds $30mmhr^{-1}$ around Osan, 2) the rain (> $1mmhr^{-1}$) area estimated from radar reflectivity is less than $20,000km^2$, and 3) the rain (> $10mmhr^{-1}$) cell is detected clearly and duration is short than 24 hr. As a result, 13 cases were selected during the summer season of 10 years (2004-13). It was found that the duration, the maximum rain area, and the maximum volumetric rain rate of convective cells (> $30mmhr^{-1}$) are less than 9hr, smaller than $1,000km^2$, and $15,000{\sim}60,000m^3s^{-1}$ in these cases. And a majority of cases shows the following thermodynamic characteristics: 1) Convective Available Potential Energy (CAPE) > $800Jkg^{-1}$, 2) Convective Inhibition (CIN) < $40Jkg^{-1}$, 3) Total Precipitable Water (TPW) ${\approx}$ 55 mm, and 4) Storm Relative Helicity (SRH) < $120m^2s^{-2}$. These cases mostly occurred in the afternoon. These thermodynamic conditions indicated that these cases were caused by strong atmospheric instability, lifting to overcome CIN, and sufficient moisture. The localized torrential rainfall occurred with deep moisture convection result from the instability caused by convective heating.

• 한국전문물리치료학회지
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• 제27권1호
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• pp.63-69
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• 2020

Background: Stroke recovery is a long and complex process. Successful stroke recovery seems to be strongly associated with patients' high motivation and committed participation. Patients' motivation is a key determinant of successful rehabilitation outcomes, but it is difficult in defining and measuring. Patients' participation is defined as the degree or extent to which subjects take part in rehabilitation activities and can be measured by observable behavior. Objects: The purpose of this study was to investigate the impact of patients' level of participation in rehabilitation on functional outcomes in patients with stroke. Methods: Forty post-stroke inpatients participated in this study. The level of rehabilitation participation was measured by the Hopkins Rehabilitation Engagement Rating Scale (HRERS). Other measures used for the evaluation were the Rivermead Mobility Index (RMI) and Korean version of the Modified Barthel Index (K-MBI). Overall measurements were made at early intervention and late intervention. Spearman correlation and multiple regression were used to measure the relationships between HRERS, RMI, and K-MBI. Results: The correlation found between HRERS total scores at early intervention and RMI total scores of late intervention was above moderate (r = 0.607, p < 0.01). RMI total scores at early intervention (p < 0.000), HRERS total scores at early intervention (p < 0.001), and disease duration (p < 0.003) were significant predictors of RMI total scores at late intervention. Conclusion: The level of participation at early intervention was associated with improvement in mobility. The level of mobility at early intervention, disease duration, and patients' participation at early intervention were important determinants of functional outcome. These findings suggest that patients' participation should be encouraged in order to achieve successful stroke recovery.

• Nutrition Research and Practice
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• 제13권3호
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• pp.222-229
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• 2019

BACKGROUND/OBJECTIVES: Aging is an imperative problem for many countries in this century, and presents several challenges for the maintenance of good nutritional status. This study aims to assess the impact of socio-demographic factors, lifestyle and health status on the nutritional status among the elderly in Taiwan. SUBJECTS/METHODS: A cross-sectional study was carried out in Taiwan. Data were obtained from the Mei Jau Health Management Institution, which is a private health evaluation provider with multiple health screening centers in Taiwan and Asia. This study included 7947 adults aged 65 years or above. The data were extracted between 2001 to 2010. Nutritional status was assessed using anthropometric data, biochemical data and dietary intake information. RESULTS: Among the 7947 participants with mean age of 70.1 (SD = 4.5) years, 20.2%, 6.6%, 10.5% and 52.5% experienced underweight, protein malnutrition, anemia and inadequate dietary intake in the past month, respectively. Age was negatively correlated with body weight (r = -0.19, P = 0.02), body mass index (r = -0.41, P < 0.001), albumin level (r = -0.93, P < 0.001) and hemoglobin level (r = -0.30, P = 0.008). Age above 70 years, gender, unmarried status, retirement, lack of education, low family income, smoking, alcohol drinking, sleep duration of 6-8 hours, vegetarian diet, multiple medications, comorbidity and dysphagia were positively associated with malnutrition in older adults. CONCLUSIONS: Underweight and inadequate dietary intake are prevalent among the elderly in Taiwan. Vegetarian diet, multiple medications, comorbidity, dysphagia and lifestyle factors such as smoking, alcohol drinking and sleep duration of 6-8 hours are risk factors for undernutrition in older adults.

• 한국추진공학회지
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• 제21권5호
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• pp.80-87
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• 2017

격벽으로 분리된 여폭약과 수폭약의 쌍으로 이루어진 파이로테크닉 장치의 성능은 격벽 내에서의 충격파 감쇠 및 폭약의 충격 감도에 의해 결정된다. 따라서 초소형 Kapton 비행편의 고속 충돌 실험을 통한 대상 HNS의 충격 점화 및 감도 분석을 목표로 EFI 기폭 장치를 고안하였다. 폭약에 전해지는 충격파의 강도 및 지속 시간의 측정을 위해 VISAR 속도 간섭계를 활용한 속도 측정 및 임피던스 정합 기법을 적용하였다. 본 연구는 비행편의 속도 및 충돌 시 발생되는 충격파의 강도와 지속 시간을 결정함으로써 소형 파이로테크닉 장치의 성능 및 기폭을 위한 비행편의 임계 속도의 예측 가능성을 확인하였다.