• Journal of Communications and Networks
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• 제12권6호
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• pp.558-567
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• 2010

In this paper, we analyze the capability of satellite broadcasting systems to offer different levels of quality of service (QoS). We focus on the European telecommunications standards institute satellite digital radio and digital video broadcasting satellite handheld (DVB-SH) standards, which have recently been proposed for satellite broadcasting communications. We propose a strategy to provide different levels of QoS for the DVB-SH standard on the basis of an extension of the interleaving scheme, referred to as molded interleaver, which supports low latency service requirements for interactive services. An extensive analysis based on laboratory measurements shows the benefits of this solution. We also present a multilevel coding (MLC) scheme with multistage decoding designed for broadcasting communications as an alternative to the existing standards, where services with different levels of QoS are provided. We present a graphical method based on mutual information for the design and evaluation of MLC systems used for broadcasting communications. Extensive simulations for a typical satellite channel show the viability of the proposed MLC scheme. Finally, we introduce multidimensional constellations in the proposed MLC scheme in order to increase the number of different protection levels.

• 대한수의학회지
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• 제39권5호
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• pp.1021-1027
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• 1999

This study was carried out to determine the effects of ${\beta}-carotene$ on the control of mastitis in dairy cows during the dry period. The relationship between the levels of plasma ${\beta}-carotene$ and the status of udder health in Holstein dairy cows were investigated. Blood samples were collected from 117 cows to compare the levels of plasma ${\beta}-carotene$ in lactating cows. The levels of plasma ${\beta}-carotene$ were $1.82{\mu}g/ml$ in healthy cows(n = 65) and $1.12{\mu}g/ml$ in mastitic cows(n = 52), respectively(p < 0.01). In the experiment to compare the level of plasma ${\beta}-carotene$ in the cows at different stages of lactation, the plasma ${\beta}-carotene$ levels were $1.73{\mu}g/ml$ in lactating cows(n = 22), $1.29{\mu}g/ml$ in nonlactating cows(n = 35) and $0.43{\mu}g/ml$ in cows after calving(n = 16)(p < 0.05).

• 아동학회지
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• 제33권1호
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• pp.63-80
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• 2012

The purpose of this study was to analyze the effects of stress perception and social support on subjective well-being according to differing levels of optimism. The participants in this study were 230 pre-service early childhood teachers, majoring in early childhood education at two universities located in Daegu, Gyeongbuk province. The results of this study could be summarized as follows. First, pre-service early childhood teachers were shown to be more optimistic, be more satisfied with life, and had higher positive emotion rates than average. They also showed lower stress perception and negative emotion rates than average. Second, the highly optimistic group showed higher levels than the less optimistic group in terms of both satisfaction with life and positive emotions. Third, the stress perception in both the highly optimistic group and the less optimistic group had an impact on their satisfaction with life, positive emotions, and negative emotions. The degree of peer support perceived by the highly optimistic group showed an impact on satisfaction with life and negative emotions, whereas the degree of parental support perceived by the less optimistic group showed an impact on their levels of satisfaction with life.

• 지역사회간호학회지
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• 제9권2호
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• pp.249-261
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• 1998

During the past decade or so in Korea, 119 relief squad members were supposed to respord first urgent or emergency cases. The primary purpose of this study was to assess what levels of knowledge and techniques in prehospital care the 119 relief squad members showed. Data regarding the knowledge and technique levels were collected from both the 119 relief squad members (n=63) and the emergency room nurses(n=46). The Results indicated that the 119 relief squad when compared to emergency nurses, showed higher scores for knowledge and techniques in some areas of prehospital care but not in other areas, However, no differences in knowledge and technique were found when the ANOVAs were calculated with two covariates : duration of their career in emergency medical services and frequency of their exposure to lectures on emergency medical technology. In addition, many respondents in the 119 relief squad group rated themselves poorly in knowledge and techniques of prehospital care, The findings imply that qualitatively better curricula should be given to the 119 relief squad members before they are allowed to play an important role in the emergency medical service system. These findings are also discussed in the context of improving the emergency medical service system.

• 대한가정학회지
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• 제44권6호
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• pp.79-86
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• 2006

The purpose of this study was to compare working mothers' sftisfaction with child day care service between those using child care centers in their workplace and those using child care centers close to their houses. their demand for better child care service was also assessed. The study findings can be used as basic information for establishing alternative solutions and developing child day care programs able to meet the different needs of mothers with preschool children. The results from this study were as follows. Firstly, there was a significant difference in satisfaction levels associated with the quality of child day care centers (programs and safety) between the two groups. There were no significant differences in satisfaction levels associated with demographic factors. Secondly, while working mothers using child care centers in their workplace were most concerned with the quality of the center, the other group of working mothers was most concerned with the distance between their houses and the child care centers. Thirdly, both groups preferred the idea that the government make child care subsidies. Thus study results suggest the need for establishing systematic efforts to increase child care services in workplaces and communities and eventually support working mothers.

• 한국항만학회지
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• 제11권1호
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• pp.45-64
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• 1997

Ship's delay caused by port congestion has drawn attention to the necessity for analysis on overall operation in port. But, in order to analyze the complicated port operation which contains large number of variable factors, queueing theory is needed to be adopted, which is applicable to a large scale transportation including ship's arrival in a large port. In this paper, a simulation model for Inchon Port was developed by the software SIMAN V and presented congestion rate under a certain scenario regarding the arrival ship's number and service levels. To develop the simulation model, types of ships and cargoes during the 1995 in Inchon Port was analyzed in advance. The results of the simulation can be summarized as follows : In order to maintain present levels of congestion rate and time with the increasing number of arrival vessels, service rate should be increased at an exponential rate. To improve the current congestion effectively, part of cargoes are needed to be transferred to a newly developing port. Results obtained from simulation can be used properly to prepare improved service levels and to plan appropriate investment strategies.

• 대한안전경영과학회지
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• 제3권3호
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• pp.55-64
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• 2001

The main objective of this research is to develop a model to select the optimal input service level for a distribution center-multi branch inventory distribution system. With the continuous review policy, the distribution center places an order for specific order quantity to an outside supplier, and the order quantity is replenished after a certain lead time Also, each branch places an order for particular order quantity to the distribution center to satisfy the customer demands, and receives the replenishment after a lead time. When an out of stock condition occurs during an order cycle, a backorder is placed to the upper level to fill the unfilled demands. With these situation, variable demand and variable lead time are used for better industrial practice. Further, actual lead times with a generic lead time distribution are used in developing the control model. Under the actual lead time model, the customer service measures actually attained for the distribution center and each branch are explained as the effective customer service measures. Thus, throughout the optimal control (using computer search procedures), we can select the optimal input service levels for the distribution center and each branch to attain the effective service levels for each branch which is consistent with the goal level of service for each branch. At the same time, the entire distribution system keeps minimum inventories.

• 한국환경과학회지
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• 제8권3호
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• pp.319-323
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• 1999

This study was designed to evaluate the exposure to benzene by residents in neighborhoods near a major roadways, by persons waiting buses, and by drivers and service station attendants while refueling. It was confirmed that the outdoor air benzene concentrations near the major roadways were higher than those further away from the sources. However, neither the indoor air nor breath concentrations were different for two specified residential areas. Smoking was confirmed as an important factor for the indoor air benzene levels. Persons waiting buses, drivers and service station attendants were exposed to elevated benzene levels compared to even the residents in neighborhoods near a major roadways. The mean benzene concentration at bus stop was 2.7 to 6.9 times higher than the mean ambient air concentration. The mean benzene concentrations in the breathing zone of drivers and service station attendants were 95 to 160 and 120 to 202 times higher than the mean ambient air concentrations, respectively.

• 한국항해항만학회지
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• 제42권6호
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• pp.406-414
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• 2018

본 연구는 해양원격의료의 서비스 특성(서비스 질, 서비스의 인지 여부, 건강 상담 서비스의 경험 여부)이 선원만족도에 얼마나 영향을 미치는지 분석하고, 또한, 선원만족도가 충성도에 얼마나 영향을 미치는지를 분석하였다. 이를 위해, 해양원격의료 시범사업에서 수행했던 2017년도 서비스 대상자 설문조사에서 수집된 데이터를 활용하였다. 다만, 본 연구에서는 해양원격의료 중 화상원격(Tele-Monitering) 서비스를 받은 선원 103명을 연구의 대상으로 실증 분석을 하였다. 본 연구의 주요 결과는 다음과 같다.ⅰ) 서비스 질이 높을수록 만족도는 높았다, ⅱ) 만족도가 높을수록 충성도는 높았다, ⅲ) 30세 미만보다 50세 미만의 선원들이 만족도가 낮았다. ⅳ) 총 승선경력에서, 5년 이상에서 10년 미만인 선원이 5년 미만인 선원보다 만족도가 높았다, ⅴ) 10년 이상에서 15년 미만인 선원이 5년 미만인 선원보다 만족도가 높았다, ⅵ) 15년 이상에서 20년 미만인 선원이 5년 미만인 선원보다 만족도가 높았다, ⅶ) 또한, 20년 초과인 선원이 5년 미만인 선원보다 만족도가 높았다. 결론적으로,ⅰ) 해양원격의료 서비스 질이 높을수록 만족도는 높았고, 만족도가 높을수록 충성도는 높았다. 따라서 서비스 질의 향상은 만족도 및 충성도를 높이는데 중요한 요소일 뿐만 아니라, 해양원격의료에 대한 긍정적인 이미지 형성에 중요한 역할을 한다고 하겠다. ⅱ) 나이가 젊고, 대체적으로 총 승선경력이 낮은 선원이 만족도가 높았다. 이는 원격의료에 대한 이용 의사가 있고, 다른 사람에게 추천할 의도가 있는 선원은 젊은 층이라고 사료 된다.

• 한국과학교육학회지
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• 제32권9호
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• pp.1405-1416
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• 2012

This study aims to analyze how pre-service science teachers' reflective thinking is presented during the microteaching process. The subjects of this study were 13 students who attended a lecture course on science teaching methods offered by the Department of Science Education of the College of Education at a national university. The simulated lessons that were performed during the microteaching process went through peer assessment and self-assessment. Then, the next set of lessons was conducted based on the assessment results. After the first set of simulated lessons, the pre-service teachers' reflection at the routine and technical levels was most remarkable in the focus dimension. In the inquiry and change dimensions, technical reflection stood out. Dialogic or transformative reflection was rarely presented. In addition, most of the pre-service teachers displayed mingling patterns of reflection levels in all of the three dimensions. The results of this study, in particular, prove that microteaching has a high level of applicability in terms of reflective thinking and instructional technology. Accordingly, there is a need for subsequent studies to create a new model that can encourage pre-service teachers' reflective thinking by structuralizing peer and self-assessment during the process of microteaching.