• Journal of Positioning, Navigation, and Timing
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• 제3권4호
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• pp.163-170
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• 2014

A pseudolite is used as a GPS backup system, and is also used for the purpose of indoor navigation and correction information transmission. It is installed on the ground, and transmits signals that are similar to those of a GPS satellite. In addition, in recent years, studies on the improvement of positioning accuracy using the pseudorange measurement of a pseudolite have been performed. As for the effect of the time synchronization error between a pseudolite and a GPS satellite, a time synchronization error of 1 us generally induces a pseudorange error of 300 m; and to achieve meter-level positioning, ns-level time synchronization between a pseudolite and a GPS satellite is required. Therefore, for the operation of a pseudolite, a time synchronization algorithm between a GPS satellite and a pseudolite is essential. In this study, for the time synchronization of a pseudolite, "a pseudolite time synchronization method using the time source of UTC (KRIS)" and "a time synchronization method using a GPS timing receiver" were introduced; and the time synchronization performance depending on the pseudolite time source and reference time source was evaluated by designing a software-based pseudolite time synchronization performance evaluation simulation platform.

• 가족자원경영과 정책
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• 제20권2호
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• pp.43-56
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• 2016

Time poverty is a kind of objective and subjective state which a person does not have a enough time to do his/her work or is in the mood to do something in a hurry. The major of family resources management has studied time as a resource to manage for long years. How to manage time has been a major part in education of family resources management. The education itself in nature has focused to inform knowledge and the disciplines of time management, to the students, on the other way, has a rare interest with a each student how to apply them or whether do in practical. Coaching is characterized as a practical learning and mutual communication skills with open questions, which help for a individual student to find his/her own goal related with time poverty or furthermore, whatever he/she wants to achieve in life. If the benefits of the education of family resources management as well as the benefits of practical learning of coaching could be merged in education on time management, the effectiveness of education to resolve time poverty is able to be increased. For the purpose, this study suggests a coaching approach in education of family resources management to resolve time poverty, by some comparisons of family resources management and coaching about time and time management.

• 가족자원경영과 정책
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• 제21권4호
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• pp.35-59
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• 2017

The purpose of this study was to explore the changes in adolescents' time use and time famine between 2004~2014. The data sources were the Time Use Surveys, which were conducted by the Korea National Statistical Office in 2004 and 2014. A total of 15,386 time diaries (9,008 from 2004, 6,378 from 2014) from adolescents aged between 10 and 18 were analyzed. Descriptive statistics, chi-square, t-test were used for the statistical analyses. The main findings were as follows: First, the necessary time of adolescents was more in 2014 compared to 2004. In particular, adolescents' sleeping time increased on Saturdays. Second, on weekdays and Saturdays, the school hours of adolescents was less in 2014 compared to 2004. But extra school hours of adolescents were more on Saturdays. Third, adolescents had more leisure time on Saturdays but less leisure time on Sundays in 2014 than 2004. Fourth, the average time famine score was lower in 2014 compared to 2004. Even so, the score for high school students was higher than 3 in 4 point Likert scale. This study provides a data-base on the well-being of adolescents and the education policies that affect them.

• 비교문화연구
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• 제28권
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• pp.67-86
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• 2012

Metaphors were conceived of as a figure of speech whose role consisted in merely ornamenting the language. However, with their seminal book Metaphors we live by (1980), Lakoff and Johnson have revolutionized the conception of metaphors by placing them as central to human language, thought and action. Cognitive linguists argue that humans tend to conceptualize abstract concepts, such as time, through more experiential and tangible concepts. For instance, it has been observed that the abstract concept of time is conceptualized as space in several unrelated languages. According to the Conceptual Metaphor Theory (CMT), TIME AS SPACE metaphor covers two more specific metaphors: (1) The MOVING TIME metaphor wherein the observer is conceived as a stationary entity, as in The end of the academic year is getting closer; and (2) The TIME AS A LOCATION metaphor wherein times are conceived as stationary points and the observer is conceived as moving relative to these locations, as in We are first approaching the end of the year. This paper aims at probing the validity of the CMT representations of time on the basis of an analysis of time metaphors in two languages: English and French. This analysis is conducted within the framework of CMT. The results corroborate the CMT representations of time, suggesting that in both languages the abstract concept of time is expressed in spatial terms. In English, as in French, time is conceptualized as a moving entity and as having extension in space. In both languages, time can be seen as bounded; therefore, one can perform actions within defined limits of time.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.484-497
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• 2021

This paper proposes an extended time uncertainty analysis approach in Level 2 human reliability analysis (HRA) considering severe accident management (SAM) strategies. The method is a time-based model that classifies two time distribution functions-time required and time available-to calculate human failure probabilities from delayed action when implementing SAM strategies. The time required function can be obtained by the combination of four time factors: 1) time for diagnosis and decision by the technical support center (TSC) for a given strategy, 2) time for strategy implementation mainly by the local emergency response organization (ERO), 3) time to verify the effectiveness of the strategy and 4) time for portable equipment transport and installation. This function can vary depending on the given scenario and includes a summation of lognormal distributions and a choice regarding shifting the distribution. The time available function can be obtained via thermal-hydraulic code simulation (MAAP 5.03). The proposed approach was applied to assess SAM strategies that use portable equipment and safety depressurization system valves in a total loss of component cooling water event that could cause reactor vessel failure. The results from the proposed method are more realistic (i.e., not conservative) than other existing methods in evaluating SAM strategies involving the use of portable equipment.

• 가정과삶의질연구
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• 제11권2호
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• pp.55-68
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• 1993

The purpose of this study were to investigate the allocation of time for housework and leisure and the causal relations between management satisfaction and all variables affecting it. for this purposes the data were collected through the questionnaire whose respondnet were 448 housewives. The major results of this study were as follows; 1`) The housework time was affected by the number of family member the age of wife and income. And leisure time was affected by the work status and age of wife educational level and income. The satisfaction level of management were affected by the wife's work status and educational level and income. 2) The relation between housework time and time management strategies was negative And the relations between satisfaction level of management and time planning time management strategies were positive. 3) Among all variables affcting the satisfaction level of management the educational level income time planning time management strategies and leisure time had direct effect And the work status had indirect effect.

• 가정과삶의질연구
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• 제13권4호
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• pp.165-180
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• 1995

The purpose of this study was to investigate the influences of family life cycle stages and perceived time pressure on strategies for coping with time constraints in housewife-teachers. The subjects of this study were 570 married women teachers who live with their husebands and children in junior and senior high schools in Taegu, A questionaire was used as survey method. Factor analysis and MANOVA were employed for data analysis and Scheffe test forpost-hoc analysis. The main findings were : First the effect of family life cycle stages on the use of personal time reducing strategies was different according to perceived time pressure. Second the effect of perceived time pressure on the use of personal time reducing strategies differed according to family life cycle stages. Third the use of strategies for coping with time contratins was found to be significantly different according to family life cycle stages, Forth there were significant differences in the use of strategies for coping with time constrainsts according to perceived time pressure.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권4호
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• pp.411-417
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• 2012

A Coarse-Fine Time-to-Digital Converter (TDC) using the single time amplifier is proposed. A vernier delay line is used to overcome process dependency and the 2-stage time amplifier is designed to have high resolution by increasing the gain of the time amplifier. Single time amplifier architecture reduces the silicon area of the TDC and alleviates mismatch effect between time amplifiers. The proposed TDC is implemented in $0.18{\mu}m$ CMOS process with the supply voltage of 1.8 V. The measured results show that the resolution of the TDC is 0.73 ps with 10-bit digital output, although highend process is not applied. The single time amplifier architecture reduces 13% of chip area compared to previous work. By reducing the supply voltage, the linearity of the TDC is enhanced and the resolution is decreased to 1.45 ps.

• Journal of Computing Science and Engineering
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• 제8권1호
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• pp.34-42
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• 2014

Time-predictability of computing is critical for hard real-time and safety-critical systems. However, currently there is no metric available to quantitatively evaluate time-predictability, a feature crucial to the design of time-predictable processors. This paper first proposes the concept of architectural time-predictability, which separates the time variation due to hardware architectural/microarchitectural design from that due to software. We then propose the standard deviation of clock cycles per instruction (CPI), a new metric, to measure architectural time-predictability. Our experiments confirm that the standard deviation of CPI is an effective metric to evaluate and compare architectural time-predictability for different processors.

• Journal of Computing Science and Engineering
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• 제9권2호
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• pp.51-72
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• 2015

Time predictability is crucial in hard real-time and safety-critical systems. Cache memories, while useful for improving the average-case memory performance, are not time predictable, especially when they are shared in multicore processors. To achieve time predictability while minimizing the impact on performance, this paper explores several time-predictable scratch-pad memory (SPM) based architectures for multicore processors. To support these architectures, we propose the dynamic memory objects allocation based partition, the static allocation based partition, and the static allocation based priority L2 SPM strategy to retain the characteristic of time predictability while attempting to maximize the performance and energy efficiency. The SPM based multicore architectural design and the related allocation methods thus form a comprehensive solution to hard real-time multicore based computing. Our experimental results indicate the strengths and weaknesses of each proposed architecture and the allocation method, which offers interesting on-chip memory design options to enable multicore platforms for hard real-time systems.